Ok, so I started losing coolant about two months ago, but I had to get back and forth to work so I just kept adding a gallon of coolant every 60 miles. Finally I have the time and space to get at it.

So I take off both heads, examine the gaskets and heads, and locate a crack in my Cometic MLS gaskets, supposing that is the problem. In addition to this, I take the heads to the Machine shop, resurface them , have them inspected (These are brand new heads a year ago) and they check out ok.

I install brand new oem replacement .010 thicker gaskets, new bolts etc., I start it up and my rad hose gets hard (sort of like in an instant which reminds me of someting when I was young) and I know that I have to tear this damn GM motor apart again.

No coolant is leaking into the crankcase, so what is going on? If my block was cracked between the cylinders and the coolant passages the oil would be contaminated, but it isn't. What might you spectulate it is?

did you use new head bolts?

, new bolts etc.,

Duh, just exactly which part of my post didn't you understand? ha ha.

I had typed "new bots", ha ha , sorry! but yes. I never even tested it to that extent! I still have it parked in the garage. SO even if I had not used new bolts, that could never be the issue!

Just a thought, did you check the flatness of the block when you had the heads off?

Just a thought, did you check the flatness of the block when you had the heads off?
Yes, I had both heads taken to a machine shop and cleaned and checked for flatness.

This thing has got me bent all out of shape. I now think that I know nothing about mechanics.! lol.

I meant the engine block. I always check the flatness of mine with a straight edge and a set of feeler gauges. Pic is not me.

oh wow, I read that wrong, no, never checked the block!

But I had the block decked less than a year ago.

Oh, well I'm sure it would still be true then, didn't know that.

I had typed "new bots", ha ha , sorry! but yes. I never even tested it to that extent! I still have it parked in the garage. SO even if I had not used new bolts, that could never be the issue!

I missed the new bolts part somehow. Or i read it an forgot. Not sure which. Sometimes the fingers work faster than the brain. LOL.

I missed the new bolts part somehow. Or i read it an forgot. Not sure which. Sometimes the fingers work faster than the brain. LOL.
K, so what is my problem? lol! You have to tell me! haha! Damn, the block must have a crack, right? What else could it be? I luv GM.

I hope they don't get bailed out!

Maybe the heads don't show the crack under cold condition!

Chances are better that the heads are cracked than the block. Most block cracks contaminate the oil pan with coolant, but you can never say never of course.

What type/source of cylinder head did you get when you replaced them?

Chances are better that the heads are cracked than the block. Most block cracks contaminate the oil pan with coolant, but you can never say never of course.

What type/source of cylinder head did you get when you replaced them?

At this hour, I do not know what type of heads I bought. I can find out a little later.

SO do you think I should pull the heads again and check them out a second time? Or just pull the whole motor and install another one? I have another motor which is supposedly good sitting in my other garage.

But I hear you and agree that cracked blocks should result in coolant leak into the crankcase.

Here's the crazy think, I could not say that one piston was any cleaner than the others. In other words, the leak hadn't cleaned or washed down any cylinder.

Here's a thought. What if I am just presurrizing the coolant area and this is forcing the coolant out of the overflow, but no water is entering the cylinders? How could this happen? Heads? Block? Can't be the Intake?

Do you think the loss of your coolant is all through the overflow?

This is one of those problems that really haunt engine builders and most of the time it ends up being a faulty part rather than a shoddy assembly. I am really pulling at straws but I think I would still be looking at the heads.

If the radiator pressures up as soon as the engine is started, even when it is cold there is a pretty good chance you can force the coolant or air the other way if you pressure the cooling system up without the engine running. Doing that will often point you in the right direction. You may get the coolant to appear where the crack is, forcing it into a cylinder. Remember to take the glow plugs out if you choose to do this, so you do not hydraulic the engine.

If it was mine I would probably take the heads back off and get them pressure tested.

Did you mean hydro lock instead of hydraulic?

I guess that depends where you were born.

Do you think the loss of your coolant is all through the overflow?

This is one of those problems that really haunt engine builders and most of the time it ends up being a faulty part rather than a shoddy assembly. I am really pulling at straws but I think I would still be looking at the heads.

If the radiator pressures up as soon as the engine is started, even when it is cold there is a pretty good chance you can force the coolant or air the other way if you pressure the cooling system up without the engine running. Doing that will often point you in the right direction. You may get the coolant to appear where the crack is, forcing it into a cylinder. Remember to take the glow plugs out if you choose to do this, so you do not hydraulic the engine.

If it was mine I would probably take the heads back off and get them pressure tested.

Thanks for your thoughtful and thorough post. It would appear that I have found the problem, SICK!

Ok, we'll see if this works. It would appear that the pre-cups fell out and then we inserted them into the wrong holes. Two cups fell out,, we installed them, staked them but apparently one was ressessed and the other pertruded. They have now been re-installed , staked, and machined. tomorrow we will assemble the engine once again and we'll see if that fixes it. We are using new gaskets again.

New bolts too right? I believe these Torque To Yield bolts are a one time use deal, stretch too much after they have already been installed once.

I used a sealent on the threads of the head bolts. This stops any chance coolant would have of going up the threads. Also a dab under the head.

New bolts too right? I believe these Torque To Yield bolts are a one time use deal, stretch too much after they have already been installed once.
I didn't order new head bolts, my machinist figured my slightly used bolts would be fine. I only ran the truck for 20 minutes.

The bolts come with a sealant on them, so I don't know that adding thread sealant helps.

The head bolts ARE TTY - Torquing them stretches them, running the engine has nothing to do with it. You really should NEVER reuse them.
I know that I've read something from GM about this, but I can't find it again...
There's some info on these on the net, but I think I saw it in the shop manual (senior moments getting more frequent :( )

On the old 6.2 engines there was a way of torquing the head bolts in a non-TTY manner. I can not remember the specs off the top of my head but I believe it was around 105 ft-lbs. It might be a good idea to double check the bolts with a torque wrench just to make sure you did not end up with a spongy one from the re-use but do not take my word for the torque specs, it is pretty late and I do not have the facts in front of me. I do agree with your mechanic and think the bolts will be fine with re-use. I have seen it done without problems in a similar case.

On the old 6.2 engines there was a way of torquing the head bolts in a non-TTY manner. I can not remember the specs off the top of my head but I believe it was around 105 ft-lbs. It might be a good idea to double check the bolts with a torque wrench just to make sure you did not end up with a spongy one from the re-use but do not take my word for the torque specs, it is pretty late and I do not have the facts in front of me. I do agree with your mechanic and think the bolts will be fine with re-use. I have seen it done without problems in a similar case.

Just for fun, when I last installed my new bolts, I torqued them to 50 ft lbs.as per instructions, then turned them 90 degrees, and the torque was about 106-110 ft lbs.

So I will reuse my new used bolts and torque them to 110. Final answer.

thats what i would do, if you happen to get a spongy one , there is bound to be a good one among the old bolts.
I never understood the TTY versus torque syndrome, as both seem to have the same result anyway.
i do question the quality of the headbolt material cause even in new sets i have found a spongy one from the get go

TTY goes beyond the yield point of the bolt, this is the point at which the bolt fails to bounce back to original shape, and after this point you will never get an accurate torque reading with these bolts again. with standard torque bolts you will torque to around 80% of yield strength, when you use a TTY bolt you torque to 100-110% of yield strength, giving you far more clamping force, your best bet is to go with ARP head studs, but i will set this disclaimer out

RE-USE TTY BOLTS AT YOUR OWN RISK, RE USE IS STRONGLY DISCOURAGED AND HAS A HIGH CHANCE OF CAUSING A FAILURE SITUATION

this has been a bluburby service annoucement :P

TTY goes beyond the yield point of the bolt, this is the point at which the bolt fails to bounce back to original shape, and after this point you will never get an accurate torque reading with these bolts again. with standard torque bolts you will torque to around 80% of yield strength, when you use a TTY bolt you torque to 100-110% of yield strength, giving you far more clamping force, your best bet is to go with ARP head studs, but i will set this disclaimer out

RE-USE TTY BOLTS AT YOUR OWN RISK, RE USE IS STRONGLY DISCOURAGED AND HAS A HIGH CHANCE OF CAUSING A FAILURE SITUATION

this has been a bluburby service annoucement :P If TTY goes beyond yield point, then the bolt lost its strenght right there, IMO you lose clamping force instead of gaining.I dont know about you, but i like to have some reserve left.But then, I take it,ARP studs use torque instead of TTY?

Maybe TTY is the reason so many 6.5's have head gasket and broken head bolt failure, cause the damn bolts are'nt any good.Altough i never had that happen yet on my vehicles.

If TTY goes beyond yield point, then the bolt lost its strenght right there, IMO you lose clamping force instead of gaining.I dont know about you, but i like to have some reserve left.But then, I take it,ARP studs use torque instead of TTY?

Maybe TTY is the reason so many 6.5's have head gasket and broken head bolt failure, cause the damn bolts are'nt any good.Altough i never had that happen yet on my vehicles.

Like anything else, if it is rated for 100lbs, it could probably handle alot more than that. Working weight and max are always far apart.

as far as the TTY's, by this time of the build money is going all over the place, and another 59 bux for bolts is alot cheaper than the labor to re-do even if its your own work. I've heard many people re-using them in your circumstance, even though they have been stretched a little, they have not been through 10 years or so of heat cycles. Choice is yours.
17 bolts per head, I just had to buy 17 of them myself.

Funny thing is that the TTY bolts for the 6.5 and the torque to spec bolts for the 6.2 have the same part number.

When I change the heads and bolts in a pita pickup and I am to sore and frusterated to do the whole TTY voodoo dance I just use a torque wrench. Yeah I use the new bolts but the TTY nonsense just is not practical all the time. If it is sitting on an engine stand I will take the time to TTY.

Like anything else, if it is rated for 100lbs, it could probably handle alot more than that. Working weight and max are always far apart.

as far as the TTY's, by this time of the build money is going all over the place, and another 59 bux for bolts is alot cheaper than the labor to re-do even if its your own work. I've heard many people re-using them in your circumstance, even though they have been stretched a little, they have not been through 10 years or so of heat cycles. Choice is yours.
17 bolts per head, I just had to buy 17 of them myself. whoa fella, i was not discussing my own circumstance, just the incidence of TTY as a form of tightening head bolts, and your stating that the TTY is suppose to stretch the bolt beyond yield is what made me replie.

I have been pulling wrenches for 40 odd years, and i can't say that the 6.5 head bolt quality has improved versus older other make diesels where head bolts where not replaced as a "have to" item. engineers love to fix things that work it seems.

omg, ok TTY is a whole weeks lesson in the curriculum as part of class S tech now....so guess what, if your not a class S i'm not explaining it to you, and if you are...you should freaking know this...so just do this...

DISCLAIMER USING TTY BOLTS A SECOND TIME INCREASES CHANCES OF PREMATURE FAILURE, DO SO AT OWN RISK....HIGHLY RECCOMEND CHANGING.

freaking people love to nit pick and then when they come and ask for advice, they don't listen, or they complain that its not right, then you know what, go somewhere else, or don't ask...problem friggin solved oy

I did not ask you for advice and I have torqued more head bolts on 6.5 and 6.2 engines than you have seen. I am pretty sure we have had this discussion before.

Check the part numbers. Check some 6.2 books.

ok, you just gotta keep stirring it up eh, listen i'm not giving YOU the disclaimer, cause i really don't care if you blow your motor...the disclaimer is for all the people who don't know any better, because personally...i always replace TTY bolts, and maybe the 6.2 and 6.5 don't need the same bolts because...uhm one was designed for boost....seriously jason, your a smartass with a big mouth, and while we all appreciate your knowledge, put a sock in it

I did not ask you for advice and I have torqued more head bolts on 6.5 and 6.2 engines than you have seen. I am pretty sure we have had this discussion before.

Check the part numbers. Check some 6.2 books.

Sounds like someone caught a bit of ego...

Sounds like someone caught a bit of ego...

Nope, it is the facts. Blueburby is in school to be a mechanic which I think is great. I did the exact same thing quite a few years ago. I do have many years of experience working on 6.2 and 6.5 engine assemblies. I am really starting to realize that I have more years experience working on these engines than a few of you guys have even had a drivers license.

Once you understand what TTY, torque to spec and torque to stretch all means you can participate in the conversation.

I can agree to disagree with Blueburby but I can not see what your comment has to do with this conversation other than stirring the pot.

Nope, it is the facts. Blueburby is in school to be a mechanic which I think is great. I did the exact same thing quite a few years ago. I do have many years of experience working on 6.2 and 6.5 engine assemblies. I am really starting to realize that I have more years experience working on these engines than a few of you guys have even had a drivers license.

Once you understand what TTY, torque to spec and torque to stretch all means you can participate in the conversation.

I can agree to disagree with Blueburby but I can not see what your comment has to do with this conversation other than stirring the pot.

Actually, there is a method to my madness. It's called maintaining common sense and proper practice. But I guess we will all now bow to you and throw common sense and proper practice out the window, all knowing great egotistical master, since God forbid anyone on the face of the planet know as much or more than you about the 6.2/6.5. Not to mention I'd have never said anything had someone not gone off ringing their own bell egging Blue on.

I also want to know where you get off telling me what conversations I can and cannot take place in. How the (not going to say it) do you know what terms I understand and such? That's a symptom of a case of major ego. I suggest you see a doctor right away, before it consumes your internet posting.

What ever happened to your tow truck taking you out of this horse and pony show anyways?

And this thread ends in perfect proof of what a horse and pony show this really is.

As soon as myself or another individual challenges the opinions or views of a list of people here that I can count on one hand, they are slapped by certain moderators.

As soon as you assclowns pipe up, nothing happens. The certain moderators are on your side. This goes way back before the good moderators left. You guys are one of the reasons a large number of the more sensible people do not volunteer their experience and time here anymore.

Now with that said, I can not really argue with blueburby, with exception to his immature personal attacks of course. He is in school learning to do things by the book. If he chooses to jump up and down saying the book is the only way that is his right and opinion. I am sure he means well.

Now with that out of the way I have a GM factory manual for an older 6.5TD engine that says nothing about the TTY process. Yes is says it is strongly suggested to replace the head bolts, but then it gives you a tighten to torque specification. The 6.2 engines were the same way, replace the head bolts and tighten to torque specification. I do not know what you guys are arguing for. I said I do the TTY process on engines on a stand but also stated that I have experience with simply torquing the head bolts and have had no problems.

If you guys think that using head bolts over are wrong I am not really arguing. I will say thay you guys probably will not comment a couple of years down the road when Typhoons head bolts are holding up fine. They were never heat cycled, I know the text books do not cover that aspect of TTY head bolts. I think he would have been wasting his money with new bolts in this case.

As you said, we're really not arguing over TTY. The main thing is really personality conflicts. We're all different people and the way we all react reflects that.

That said, if you have such a problem with this forum and the moderating staff, why on Earth are you still here? I don't think there'd be any skin off anyone's back if you just peacefully and honerably left, as I plan to do from this thread following this post.

It really isn't challenging views that the mods and group of members are against. It's opinions that, be right or wrong, can get someone whom does not know better in serious trouble, possibly costing them more money than they have. Not everyone here know as much as you, Blueburby, Green Machine, WhiteK2500, Dave, Bison, knkreb, lost without spark plugs, or myself. You never know who might be reading this. You must think about those that are not mechanics, who have had no schooling to be a mechanic, those that are rookie shadetree mechanics. Maybe someone who's never run into something like this before. When in doubt, err on the side of caution, and remember, those active in the thread are not the only ones viewing it.

this started as a useful discussion, but it's denigrating like a filibuster session in the House of Commons with Giles Ducept as referee.

And this thread ends in perfect proof of what a horse and pony show this really is.

As soon as myself or another individual challenges the opinions or views of a list of people here that I can count on one hand, they are slapped by certain moderators.

As soon as you assclowns pipe up, nothing happens. The certain moderators are on your side. This goes way back before the good moderators left. You guys are one of the reasons a large number of the more sensible people do not volunteer their experience and time here anymore.

Now with that said, I can not really argue with blueburby, with exception to his immature personal attacks of course. He is in school learning to do things by the book. If he chooses to jump up and down saying the book is the only way that is his right and opinion. I am sure he means well.

Now with that out of the way I have a GM factory manual for an older 6.5TD engine that says nothing about the TTY process. Yes is says it is strongly suggested to replace the head bolts, but then it gives you a tighten to torque specification. The 6.2 engines were the same way, replace the head bolts and tighten to torque specification. I do not know what you guys are arguing for. I said I do the TTY process on engines on a stand but also stated that I have experience with simply torquing the head bolts and have had no problems.

If you guys think that using head bolts over are wrong I am not really arguing. I will say thay you guys probably will not comment a couple of years down the road when Typhoons head bolts are holding up fine. They were never heat cycled, I know the text books do not cover that aspect of TTY head bolts. I think he would have been wasting his money with new bolts in this case.

Alright Guys! That's enough! You all seem to push and push waiting to see if I'll step in, as you egg eachother on by continuing to post. IF someone says something you don't like or it offends you, use the report post button, do not take it into your own hands as that never ends well.

Its just good practice to not reuse TTY headbolts. Remember we are not all Mechanics, some of us have no choice other than to do this work in our own backyards with a very tight budget. No matter how tight the budget, something like TTY headbolts shouldn't be reused, They can be but they shouldn't be.

I do see that he just put those headbolts in, and they were new when he put them in. I would reuse them too, if something went wrong the first time the engine was fired up and the heads had to come back off. I'm cheap at times and if I break it its no ones fault but my own.

You all need to knock it off. I don't care who is wrong, you all need to stop egging eachother on. I won't tell any of you again. Discuss things like civilized people like this section is know for.

Keep arguing and I will give out vacations. That goes for Jason, RC, blue and anyone else, for that matter, that wants to fight here.

This forum is not going to be a personal gong show for anyone.

This one's locked.