Got a 94 Suburban that goes through coolant, slowly, but goes through it. It does not seem to be external. I have looked and looked, but nothing outside or inside the vehicle. I have watched the oil and changed it very regularly. Nothing in the oil. It does not go through any oil to speak of. Maybe 1/2 quart between changes, which are around 4K miles.


SO, it must be going internal somewhere....http://www.dieselplace.com/forum/smileys/smiley19.gif, but where? I have also watched the water level and have not found any residue from oil at all. I am now thinking I have a failed gasket or a crack somewhere, but where.


Truck runs very good, but only gets about 11 miles a gallon when hauling and maybe 14.1 empty. Should be lot's better. GM replaced the 6.5 longblock complete at 75K due to a failed timing gasket. The mileage has never been the same. Used to be 15 and 21 on a good day. The dealership states all is in spec. Truck has never overheated.


Questions are these.


1. Compression test? Done through the injectors?


2. Testing for a gasket failure? Thoughts?


3. Smokes under heavy load up grades. EGT climbs to 1200+ fast, (post turbo). Reading other posts, this seems not good. Wasted fuel.


Thanks

Depends on the fitting you have for the tester, but remove all the plugs or injectors for the test, so the engine spins easier.


Could be a leaking head gasket, dripping down on the exhaust and evaporating before you could see it - won't show up in any oil\coolant\radiator check.


Could also be the heater hose fittings, particularly the one in the thermostat housing, but check them all four.


Could be the coolant blockoff plates at rear of the heads, same position as the thermostat housing\crossover manifold.


Could be a leak where the plastic radiator tank(s) crimp onto the aluminum core.


Could be weak radiator cap - 16-18psi.


Check vacuum at the vac pump for ~25"hg, and at Wastegate Servo cannister for ~15"hg for black smoke, low power.

gmctd. Thanks for the information


Guess I will be busy for a few hours looking around with the information you gave me. I have already replaced the cast connector with a machine steel fitting from the TStat housing to the heater system. It was weeping oh so little and I was sure that was it. Seems all it did was slow the leaking down a bit. Still more discovery.


I have noted some staining around the lower radiator hose, but have never found it wet or damp. The radiator system holds pressure for several hours after shutdown. Would any cracks or gasket failures generate excess pressures in the radiator system? Seems I should locate a cooling system pressure tester and go from there.


I have not noted any smell or white smoke from the exhaust, so I tend to shy away from gasket failures or cracks. With all of the potential areas you pointed out, one of them will have a clue, I HOPE. http://www.dieselplace.com/forum/smileys/smiley4.gif


Thanks

Added pressure in the radiator would depend on where the crack\leak was -


Cylinder area - block or head - would allow compression pressure into coolant - compression pressure is ~400psi and up, also considering combustion pressures. Oil\fuel in coolant is symptom


Upper edge of heads around intake manifold would allow coolant into crankcase - coolant pressure is 15psi and up.


Adjacent ehxaust port would allow exchange of coolant\exhaust, depending on which pressure was higher - coolant at idle, exhaust under load - exhaust may have distinctive odor at idle.


Adjacent intake runners would allow coolant into cylinder, long as Boost was less than coolant pressure - coolant would disappear with no external symptoms - exhaust may have distinctive odor.


Block water jacket adjacent valley area woud allow coolant into crankcase - coolant in oil is symptom.


Block water jacket adjacent oil passages\lifter bores would allow higher pressure engine oil into coolant.


And, again - black smoke under load, if air filter is clean - check vacuum system, pump to Wastegate.

Well, now the plot thickens.... Driving home last night, the Suburban made a loud noise, like something in the fan but a little more metalic in sound. This lasted less than 3 seconds. I pulled off the highway, opened the hood and nothing. Truck was still running fine. All gauges normal. Not a noise to be heard, other than the diesel sounds. Looked around and nothing under the hood moved into the fan. The belt was complete and intact. No fluids on or in the engine compartment. Closed the hood and drove home. All the gauges normal. Good power. Boost and EGT acted normal.


Got home fine and poped the hood in the garage. All looks as before, clean and no fluids anywhere. Pulled the dip stick, for some reason, and noted that it now blows fumes or oil vapor out of the dipstick tube. I would guess ~1 pound or less of pressure, but it does look interesting in the cool evening air.


Now I am getting worried. I have never noted any "blowing of vapor" from the dipstick tub or the oil filler neck. There are no signes of any oil around any of the gaskets, so the pressure seems very light.


Thoughts.

The vapor is most likely glycol burn off the oil. In other words, you have coolant mixing with your oil. When my head gaskets blew, I had gallons coolant in my oil. Once I replaced the head gaskets, it took about 4 oil changes to get rid of all the vapor coming from the dipstick tube.

On my last holiday trip, I've occassionally seen some vapour coming out of the oil filler neck when opening the cap not long after shutting down the engine. It didn't look as if there was pressure involved, just some vapor from hot oil after the engine had to work harder than usual, towing my camping trailer. The amount of vapor was small, it went lazyly away while I was adding some oil.

It didn't look like anything to worry about and seemd normal. Afaik, oil can always give some gas away, that's why the diffs are vented.

I'm not sure if there was vapor from the dipstick, may very well be --- I pulled it before I opened the cap.


BTW, the sound you mention: A couple of times I've heard a loud BANG as if a stone hit the windscreen, but I've never found out where it came from. The windscreen was undamaged, and the noise remained very mysterious. It was very loud, so if it had been stones, they _would_ have caused quite some damage.

When changing the oil after the trip, I noticed that oil was spilled all over the pan, on the bottom of it. There was no leak, and we couldn't tell where the oil could have come from. We cleaned it off, and it didn't come back within the last 12kkm; the BANG didn't either.

My theory is that when towing without boost pressure and the engine working harder than usual with the oil level a bit high, some pressure built up, due to increased blow by and a crancase ventilation maybe not working as it should because the pressure on the intake wasn't in the range it is designed for. Thus, the pressure found some way to be released, maybe through the oil pan gasked or some blow off vent, making the BANG and taking some oil with it, spilling it over the bottom of the pan.

Hm, do you have some oil on the pan or somewhere else where it shouldn't be? If you have some, it could eventually explain the mysterious sound.

There is a big difference between a little gas being given off by the oil after shut down, and steam venting from the dipstick tube. Hold a small mirror above the dipstick tube. If it fogs over like in the bathroom when the shower is running, then it is stream, and a sure sign that coolant is finding its way into the oil.<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><O:P></O:P>
<O:P></O:P>Plus given the fact that your truck is consuming coolant, I would say you have a small head gasket rupture. Edited by: Juancho

A small part of me tends to agree with the vapor burn off being Glycol, though it has no real smell to it but the oil level never changes. It is enough pressure to make the dipstick tube look like a small exhaust pipe. It looks like more than oil vapor burnoff, but is hard to tell. Having had a gasket failure with the original engine, it had gallons of glycol in the oil. I changed the oil several day's ago and it does not move from the full mark. That is normal for this engine. It does not use oil, just water lately. The engine has ~50K miles now and should start to be getting good mileage, but that is still low.


The noise was a "metalic clatter" like a wrench in the fan. A very distinct noise. It seemed to be a "solid" noise involving something with mass and weight. If the conditions would have been different weather wise, I might think it was the "Anti-lock" brakes engaging. I was braking at the time and making a corner, but it was dry and at correct speed's. I was not in any panic stop or turn at the time. (The first time I heard the ABS noise it scared the crap out of me.) The noise came and went so fast, it COULD have been the ABS, but it sounded different......


What makes sense to me would be to locate a "sniffer" of sorts and tell me exactly what the vapor is composed of.


At 50K miles, should there enough wear to have a blow by? This engine has been taken care of and not mistreated. My goal was to get the entire vehicle to last 400,000 miles minimum. That WAS the beauty of diesels. I guess I was kidding myself.

Hm, Juancho, maybe I misunderstood 94Burban:

&gt; it now blows fumes or oil vapor

Does that mean 'venting steam' or 'a little gas being given off by the oil'?

(Mine gave off a little gas, I'd say. If his does, too, it should be normal?)

Just an idea: Is there any chances that some air is bleeding out and thereby lowering the coolant level? I've noticed that the coolant level goes down when the cabin heater is used (turned on) after water has been drained from the system. Two times or so I had to refill until all the air went out. The air seems to stay in there until the vents of the heat exchanger are opened.

One of my previous cars was slowly loosing coolant in the winter, i. e. when the cabin heater was used. The particular make was somewhat infamous for leaking heat exchangers, but I didn't keep it long enough to find out exactly. There wasn't any visible leak, and it didn't loose much water.

Maybe the small amounts of water leaking out of the heat exchanger were blown out with the air going through it, though there wasn't any smell of coolant.

Do you still loose coolant whith the heater turned off?

This may be totally out of wack, but...
Have you ever heard of something called "crankcase explosion"? I don't think it is a big concern on smaller diesels. However, as I have come to understand all diesels have in place engineering measures to prevent serious damage or injury to the operator. I will attempt a very brief description of what exactly a crankcase explosion is and how it is "controlled".

When a diesel runs normally, there is a small amount of fuel that leaks by the compression rings. As we all know, I hope, diesel engines are not governed by air intake, they are governed by the amount of fuel that is admitted to the combustion chamber. Common sense should dictate that when you are running WOT, or under heavy load conditions, you are admitting a lot more fuel to he chamber. Thusly the amount of fuel of fuel "blowing by" is outside of the "acceptable leak rate". It does not take a degree in engineering to figure out that atomized fuel swirling around in the crankase, under high temperature conditions is an explosion risk. What engineers have done to "prevent" this from happening is the intiation of crankcase scavenging. You may know this already as PCV, or positive crankase ventilation. By continually drawing fresh air through the engine you constantly remove the flamable vapors. Problems arise under extrem load conditions when the scavenging system is unable to keep pace with the amount of fuel vapor being put into the crankcase.
When a crankcase explosion does occur, it is extremly loud. On the larger engines it sounds like a cannon blast. On smaller engines the sound would be more like that of that of the "rock" you describe. The biggest factor in the sound is the volume and resonnance of the crankcase. The noise is accompanied by a subsequent surge in pressure. If you think about it, it is very similar to a combustion chamber. However, there is no exhaust port for the gas to exit. Engineers have incorporated pop-off valves to prevent the cast iron crankcases from becoming grenades. When the valves relieve pressure they blow out a lot of oil and make a huge mess.
In short, I suspect you have experienced a crankcase explosion. Wittnessing the external deposits of oil, and the "vapor" (smoke) coming from the dipstick, would lead me to believe that is what happened. At this time I can offer no explanation for the continued release of pressure. I hope this helped, or was at the least, educational.

Might do a compression check, 'Burb - remove all glow plugs so crank will spin easier, disconnect Engine Shut Off Solenoid, all cylinders ~400psi, within 25psi.


Also, with ambient dropping, vapors will be more visible throughout the cooler seasons - compression check may still ease your mind, tho.....Edited by: gmctd

Flywheel torque plate crack ring a bell GMCTD for mysterious metalic noise, any tips for him to check that

Flywheel torque plate crack ring a bell GMCTD for mysterious metalic noise, any tips for him to check that


Remove and inspect or even replacement might be the only way. Pay close attentiont o the torque convertor to flexplate mount bolts. Also make sure it is the 6 bolt convertor and flexplate. The 3 bolt gasser convertor will fit and work but it often fails with use. Just a thought from what I have learned with these motorsEdited by: bowtie

Just my experience--My '94 6.5TD was using a minor amount of coolant when I got it. I checked the entire system for any external leaks, and could never find any. Never any increase in oil, no smell to exhaust. I passed it off as being a bad radiator cap, and added about a gallon a month, untill I finally bought a new one. NO DICE. A few short months later, the problem became extremely apparent--the coolant system became pressurized and the exhaust turned white--of course, by now you all know that I had either blown a head gasket or cracked head. I never tore it down to find out, I just had a reman engine put into it's place.


My theory--with the reputation these trucks have on heads/gaskets, I would bet that the coolant is leaking into the combustion chamber and burning off. The amount is so slight that there's no white steam, and no apparent loss of power.


I hope, for your sake that I'm wrong, but mine shared the exact symptoms.

As you guys already know, I am with JBT4 on this one. With a minor coolant leak the oil level will not change. You are burning off the glycol before it has a chance to mix with the oil, hence the steam coming out the dipstick tube.


Honestly, I have no doubt that you have a ruptured head gasket, but I can't say that I blame you for being in denial. Trust me that is not a dig. After having just replaced both head gaskets on my '95 Burb, I would be in denial too. Even if coolant were flowing from the downpipe.http://www.dieselplace.com/forum/smileys/smiley2.gif


Use the mirror trick I mentioned earlier. That is a simple way to tell if it is steam or just oil vapor.

&gt; I suspect you have experienced a crankcase explosion.

THX for the explanation 2dr, I didn't think of it that way. With no boost pressure but load, there could have been more fuel left (unburned) than usual, and that would go somewhere ...


&gt; Flywheel torque plate crack

Are there other symptoms of such a crack? Would it crack several times, making that noise?

I saw remnants of GMCTDs after he swapped it out, went from an intermittent noise/knock to continious, I'll let him expand on it so I don't tell it wrong.

Mine made a ticking noise - like a bad lifter - on decel, then quieted down for several hundred miles Edited by: gmctd

The crankcase explosion makes sense for the one bang, but in my case it was a rattle or solid tap with duration. It seemed to last for several seconds than went away. It was a fast rattle like an air hammer. Thought something went through the valve train kind of noise. Checked the airfilter and it was clean, just like it was a month ago when I changed it. Removed the boot from the airfilter cover to turbo and rotated the turbo. Smoooooth. Started engine and no strange noise or movement from the turbo. I then removed the "Tuna can" from the valve cover checking for a restriction. It was mostly plugged with a grease like goo. What would cause 15-40 oil to change states into a grease like substance? Water make oil white and creamy. Glycol breaks oil down to a solvent like state, This was black and snotty.


Anyway. cleaned up the mess in the tube and tuna can. Replaced the parts and started truck. The flow a vapor has slowed to less than half out of the dipstick tube. Next day or two will tell.


Regarding the vapor from the dipstick tube, with a mirror, it does not fog.http://dieselplace.com/forum/smileys/smiley4.gif


BTW. What part of putting my hands over my ears and saying LA LA LA sounds like denial.....


Removal of the injectors or even the glow plugs is NOT going to be a fun job is it? That beautiful down pipe is now dead in the way.


Thanks very much for the replies and posts. All of you have provided excellent thoughts and input.

That description points more to a shift in timing, where injection went advanced.


Mine did that one summer nite in a freak cool spell - temps went from hi 90's to low 50's - when the alternator began pegging the gage - both directions - due to loose field supply connector.


Ran really great for about three weeks after that, then settled back into it's old routine, till I later strong-armed it with a Tech-II - nothing like walking softly and carrying a big stick, around these EFI 6.5'shttp://dieselplace.com/forum/smileys/smiley2.gif


Yours coulda been where the pump passed a slug of bad fuel, or you need to check your wiring harness and grounds, now the weather is changing to cold and damp.


Happens all over this time of year - rash of complaints of missing, skipping, hesitating, hard starting, excessive noises, etc .


Every year..........

The black goo in the CDR is soot-thickened oil - could be excessive blowby, or could be CDR has never been inspected and cleaned, and the accumulation is commensurate with actual mileage and vehicle useage........... Edited by: gmctd

Does the CDR can just pull out of the valve cover? I've never checked mine out.

94Burban - what rpm are you turning at 55mph? And you got stock tires? We have the same drive train from what I can tell....


Also I'm with w_huisman - it just pulls out?


thanksEdited by: Bumpin' Yota

Yes CDR just pulls out, may have 1 bolt in it's tube support bracket; go to FAQs GMCTD has an excellent post on how it works and a troubleshooting procedure for it.

After the removal of one bolt holding the tube in place, it just pulls out. I have never checked this item before, so it very well could be 137,557 miles worth of goo. After I get home this evening, I will remove the dipstick and see if it still vents. Cleaning this can took a bit and a number of solvent rinses, but it is clean and flowing now.


Now back to the original problem of coolant loose. I live in the Seattle area. Any place I could go and have the exhaust gas tested for Glycol content? This would surley answer my question on where the coolant is going. If I can prove the problem, I have no problem with removing the heads and checking for a bad gasket or cracked head. I just kinda refuse to "Swap and hope" for results.....


As far RPM at 55, I will check for sure but I believe it is close to 2000. I am running Avon 265's from Les Schwab.


GMCTD. You mentioned a freak timming advance and "hitting" it with a TechII. The noise I heard sounded just like what you described. Injector timming went wacko for an instant. It seemed to be that kind of a rattle. What did you find out from the TechII?

The CDR has a diaphram that was more than likely dissolved by the solvent.

If you scan it before the 50-start deadline, you may get a History DTC or several - could tell you what happened............

I'll order a new CDR can today. Hard to believe solvent could desolve it, but what the heck. Actually going to take the truck to a dealer in the area and have them take a peek with a TechII. This is weird for me as I tend not to trust dealerships, based on prior experiences. But also cannot afford a TechII scanner either.


On another note, with the 3" exhaust I have, can I get a better flowing muffler, and from who. The sites I have stumbled into seem to have complete systems, but no parts or pieces. Also am telling the "accountant" we need new glow plugs and injectors. Went with AC for the glow plugs, but what about injectors. Of course I need a bit more power, so stock is out the door. Any thoughts here???


Depending on the report from the dealer, I may be pulling the heads and having them checked for cracks as well as replace the gaskets. Too many thoughts in this thread have convinced me that this will be something to check anyway, unless I find another answer that make sense to me.

Before going to the dealers, you know anybody with a Snap On MT2500 scanner(most independent shops have these and will scan for lots less than a dealer), you can do the paperclip for active codes but IIRC you need a scanner to see the historical codes; ones I call "soft codes" the ones that are saved but don't set a SES/MIL lite

Bumpin' Yota Checked the RPM at 55 and it is 1950.

Went to the dealer for the "test". They stated that they could not fiind a leak of any sort in the coolant system. Said it was a pressure tested. They also stated that there was nothing wrong with the glow plugs, new two days before, though they believed there was a ticking injector, #6. At least that jived with the SES #96. They also insisted there where no codes in the computer. I asked if they checked them and then asked the service manager and mechanic to come with me to the truck. It dumped 3 seperate codes. I got the diag for free this day. Said several other things as well...... What dumb poops.


Bought a compression tester and did a test. DS 405,400,405,400. PS 400,350,360,390. These where around 5-6 cranks. Pulled the PS head and found that the gasket "appeared" to be intact. Small crack between Intake and exhaust valve of #2 and #8. Seems strange! This is different than expected as the compresson tests are in order of front to back 2 4 6 8 ,There is a slight trace of coolant residue on the head side of the combustion chamber near what must be a gasket weeping..... #2 and #4 cylinder.


What is the general failure of the head if cracked? I am going to now take the DS head off as well. Why not.... Piston tops appear clean and have no material erroded away on the edges. The two with lowest compression are sooty, but have no buildup. I do hope this stops at the heads...... The engine has about 60K miles now and has been at temps of 220, according to the factory gauge, pulling a load uphill. Never hotter as I simply back out of the throttle. Is this too hot? Will going to the high volume water pump and dual T-stat keep it that much cooler AND keep the heads intacked??????


Are there "things" can be done to keep this from happening again to the heads, or is the 6.5 that fragile????????

Sure - any head\block shop familiar with Diesel head repair can put the available kit in each head for you.


They'll knock out the bore plugs for the coolant passage between the valves, install the tubing, new freeze plugs, valve job and you're good to go.


It's a common repair, but make sure the shop does Diesel heads.


And, don't forget the new nylon rocker arm keepers, while it's down.


The '97 cooling mods - dual t-stats, HD 130gpm waterpump, re-calibrated fan clutch, 11-blade Dmax fan - and mandrel-bent down-pipe to lower EGT's somewhat, will put any overheating problems to rest.


Symptoms of extreme overheating are loss of coolant thru failed head gasket(s), cracked head(s) from repeat or extended overheating, and FSD\PMD failure.


220 isn't bad temps, if your ECT gage is good, or reads high.


For best hiway-use fuel economy, 215-220 deg is most efficient - more BTU working the pistons, less working the atmosphere.


For around-town-use, stop-and-go, a\c cranking cold, 180's is probably more useful, less loading on batteries, starter and Inj Pump\PMD .


Edited by: gmctd

I'm glad you we're so willing to pull those heads. The problem wasn't getting any better 'till you did. I commend you for jumping into the work.


other than the cooling mods, you can lower the compression and add an IC to further reduce stress on the head.


I replaced a cracked piston(#6) and put on a deep PML pan and I can't get my engine to have a spike in coolant tempature. Pyro temps are lower also. 20 psi sustained boost never took the pyro over 650*f on a 50* F day, unloaded.


Loosing compression is hard on the engine, it seems.Edited by: quantum mechanic

Regarding the compression. Is it common with this type of failure to also have a lose in compression? The gasket failure was a weep and the cracks in the head between the valves are in different cylinders than the lower compression cylinders..... I have this feeling that I will be going deeper into this motor unless the experience of others is that this is related to the heads/gasket only..... Again, it only has 60K miles on the engine and has been taken care of. Worked, yes.. Beaten, no.

Could be valves leaking - cylinder scoring would tell another tale

Just finished removing the other head. It to is cracked between intake and exhaust. Also ran a mike through the bores checking for out of round, gauling, scoring...... There is still a very clear cross hatch pattern in all of the bores. No ring scares in the walls. This is still with the pistons in place. There is no real differnce in the bores. They all seem very round. What I did notice though was that I can see the top ring in all of the bores. I am guessing that this is normal as these pistons grow with heat. True......


The pistons all appear very clean with no visible cracks or scares. There is no real ridge at the top of the bores. At least not enough to hook your finger nail on. Another thing I noticed was how easy it was to remove the heads once all the bolts where out. The gasket was attached quite well to the head, but left nothing on the block. I would have thought this would have been sealed better, with say Copper Coat or the like.


Anyway, I hope for a bad valve report from the shop..... Being this young of a motor, I hope the bottom end is in good shape.

Try to move each piston radially in it's bore at top dead center - should be difficult to move minimally, with no slop.


If you can easily pull the pan, wipe the machined block surfaces down with a towel, then do the same again with a towel and lacquer thinner, so rails are clean and dry, and no oil is visible.


Take a coffee break, then check the surfaces when you return for black vericose veins in the areas adjacent to the three center mains webbing.


No veins = no cracks = good block.


Check your harmonic balancer for extruding rubber insulator, or missing pieces - replace if found.


Check accessory drive pulley for cracks\deterioration of the cast rubber webbing - replace if found.


Check pulley for severely offset mounting bolt holes, where rubber webbing has stretched, allowing bolt bosses to contact cast-iron pulley crosses - replace if found.


Will definitely save your crank.


Use FelPro head gaskets - if package instructions state with no sealer, then no sealer.


Use new head bolts - originals are torque-to-yield, which means they are stretched and should not be re-used.


Use Black RTV on oil pan and valve covers, as from factory, for no leaks.


Use Black RTV on rear oil pan rubber seal - same area where oem applied rtv sealer to original. Edited by: gmctd

I wound up not using copper coat when I resealed my head recently. I didn't have it and the headgasket came wrapped in celophane and had a slicky coating already. I would take the smooth cylinder walls as a good sign.


I noticed there's a hairs width between the top each piston and the cylinder but lower on the shank it's tapered to fit snuggly.

Ok GMCTD. I give. I have talked with 8 shops in the area about the 6.5TD heads and none have any idea about the "kit" mentioned. I have taken the heads back to my old machinist, who has done large and small gas and diesel work for me over the past 20 odd years. He has done a large number of these heads, but has not heard of the fix mentioned. He is more than happy to learn about and install such, I just need more information, please, on the kit?


He is going to pressure test the heads and I will know more tommorrow. He looked at the heads and pointed out four leaks in the gasket in just a few seconds. He is betting there is a carbon buildup on several of the valves, which explains my low compression in two cylinders. He also has seen these cracks before and believes, still going to pressure test, that these cracks are in the surface material and do not go into the water jacket itself, which explains good compression on cylinders with cracks. These cracks are only visible between the valve seats. If the pressure test comes out good, I am still going to have the heads magnifluxed for insurance.


The machinist also states he has seen this on many 6.2 and 6.5 heads he has machined and knows of several that are sill in service 100K miles later, with the cracks not being welded.


Please don't take me wrong here. If need be, I'm prepared to go GM and purchase new heads, $895 bare a piece, if that will get me down the road for the 300K+ miles I am after from a diesel AND do the "kit" mentioned on the new heads. I am also going to install the high volume water pump and T-stat. Again, I wish for a truck I can trust. If all else fail's, I'll find a Cummins and install it as I love my Suburban that much.


All I am after is to do the job right. Like the rest of us, getting a call from the other half stating the truck died again stinks.

GMCTD. I checked the other items you mentioned and all is well. The one that scared me was the viens in the block, but it looked good after the Burbon, er, coffee break. http://www.dieselplace.com/forum/smileys/smiley2.gif


Thanks again for all of the great input and information....

Ok - let me check my files and sources - might even get you a brand name.


Get right back with you.......

K-line makes head repair tools and parts for the head repair services - the kit for the 6.2-6.5L crack repair is K3900.


The shops should know about K-line.


Might even be Kline or Klein company.


Detroit Gaskets makes the pre-coated head gasket sets.


Go to the Fel-Pro site for instructions on prep and useage of their head and engine gasket sets.


*Some info brought to you courtesy of the folks over on theDieselPage.Edited by: gmctd

Awsume, Found it!!!


http://www.klineind.com/cgi-bin/klineind/cgi-bin//category.c (http://www.klineind.com/cgi-bin/klineind/cgi-bin//category.cgi?mode=view&amp;category_id=292) gi?mode=view&amp;category_id=292


Reading it, though I am note a machinist, it appears to be a tool and kit used for repair if the seat is replaced. I will print the information and bring it to the machinist tommorrow.


Most Excellent!!!!!

Well bad news and good news.... My heads are both shot! No less than 3 cracks per head. On each head , on the edge of the pre-camber and head surface, they leak. Welding is not an option here as the metals are different. I watched the pressure test on the second head as the machinst tested it and the head suface bubbled like a bubble machine. My heart sank. Though the kit shown above could fix one area of leaks between the valves, I would never completely trust the engine.


Good news is that I found new heads, will contact the 800 number tommorrow, for $350 ea new and complete with valves and springs. Herei is the link, please save me a set....


http://www.acheinc.com/


Question now is this. To do this engine right what should be done to get 300K+ miles from the engine?


I believe the following.


New heads. New 18:1 pistons. 4" exhaust. Water pump upgrade w/goodies.(Fan, T-Stat housing, hoses....), Marine injectors. Chip. Intercooler. FSD w/heat sync. Ceramic coating in combustion chamber. What did I miss? Not a want, but a need...


With the 18:1 pistons, will I NEED to upgrade to a large turbo? What boost levels can be achieved with the stock turbo? If I go hunting in zero degree weather for week, will I be able to start the truck with these pistons?


Thanks.

If you start ceramic coating, do the top of the pistons the inside of the exhaust manifolds and crossover,if possible. The turbo upgrade should be done with a little forthought. The smaller one is better suited for most low rpm applications, such as daily driving.

I agree with the ceramic places mentioned, but isn't the piston swell to much for the coating? I have played with ceramic a lot in the race cars and desert racing motorcycles and quads, but never a diesel.....


As far as the Turbo, a GM8? and do I need a different exhaust manifold for it as well?

The Gm-8 will fit your exhaust manifold, not that different, just a little better flowing and different WG-arm, vertical instead of horizontal.


I've heard there were versions of this engine that were ceramic coated in the places I mentioned and it makes since to keep the heat moving.Edited by: quantum mechanic

If those are '97-up heads, GM corrected for the between-the-valves cracking situation with redesign including larger coolant passages between the valves, according to some sources.


Those and the HD hi-flo waterpump, dual t-stats, fan and clutch ('97 cooling mods) should do that trick.


Have the crank and rotating assy's balanced for the 18:1's, and most folks who have upgraded praise the DSG timing gear set replacement for the timing chain set.


Completely stabilizes cam and Inj Pump timing - check Kennedy Diesel site.


Lower compression will require longer glow times, so a set of the Hi Heat glow plugs also from Kennedy Diesel.


Also carries the recalibrated lower temp cut-in fanclutch.