Greetings http://www.dieselplace.com/forum/smileys/Big Smile.gif Just picked up a 94 6.5 TD. It had quite high miles on it (357,000 km).. and it seems to have a bit of blowby..

It didn't show this when i first test drove it and tried it at the dealership... but when i got it home (2 hour drive) there was noticable smoke emitting from the dipstick tube..

Is there any engineflush or likewise that i can use to free up the rings somewhat?

Never owned a diesel before.. i have the funny feeling i'm gonna be come very knowledgable this engine whether i like it or not! haha..

Thanks,

Dave

Wheatking,


with nearly 400,000 km you could be leaking compression through the valves, rings or because of irregularly worn cyclinders ( not round).


My '94 is still fresh with 60,000 on a new block, but it has the same blowby. It doesn't affect performance that I can tell, except that it comsumes about a 1/2 quart of oil every tankful (450 miles) or so. I was more concerned with this when I first noticed it and now( after 60,000 miles) it seems somewhat acceptable. I'm working up to checking the compression, valve spring tension and then removing the heads for a better look at the valves.


I think that a lot of 6.5's are running with a little blowby.Edited by: quantum mechanic

naw it doesn't affect performance at all.. except it's blowin oil out the valve cover and out the dipstick tube.. otherwise it's workin great :)

never had a diesel before.. i know in my gas engines i used mopar combustion chamber cleaner to get rid of carbon deposits and free up the rings.. but this isn't a gas engine..

I know "0" about diesels.. except lotsa squish and lotsa torque :) is there anything i can dump in the crank case to clean the engine somewhat.. for all i know it could be a clogged PCV valve.. but i just got the truck last night so i haven't had time to "mess" with it.

Thanks,
Dave

Wheatking,


Based on my own personal experience, the oil is coming out of the valve covers because they need to be resealed with new gaskets. The valve covers have to follow the irregular shape of the head around the head bolts and it's hard to keep them from leaking except to clean it up and reseal it. With a little blowby you'll see oil (vapor)from every gap on the block. The engine is designed to collect this vapor and burn it. This is the metal can (CPRV) that has a hose going to the turbo intake. The better you can seal your valve covers the more of the oil vapor you'll burn. Otherwise it will make your engine bay filthy with oil and grime.


also, because you're recycling this oil through the intake you might see oil around places where you're intake is in need of a better seal.

Cool.. i'll have a look at it tonight..

i realize there's gotta be some blowby.. high compression plus boost.. lol.. the rings can only seal soo much..

Is the can you speak of like a catch can? (i've boosted several gas engines.. blowby is normal.. so is sloshing oil out of the valve covers.. i've used a catch can with a drain back to the pan connected to a vacuum source before the turbo so the oil wouldn't be flinging across the compressor blades of the turbo..)

if i'm replacing the valve cover gaskets.. anything else i should do while i'm in there?

Thanks,

Dave

First chance you get you should relocate the driver for the fuel solenoid(currently mounted on the IP) to a location away from the engine's heat. I have mine mounted top right in the picture but other people have their spots too. The exta wire in the circuit adds a little resistance to help throttle response. It's about impossible to get the blackbox off. I personally have to remove the intake to accomplish this feat so I took the oppertunity to die grind all the intake runners and the bowl to improve flow through the lower intake and put a freash gasket between the block lower intake with plenty of orange gasket sealer around the intake runners.


http://dieselplace.com/forum/uploads/95C_fsdcooler.jpg


and I feel compelled to mention the restrictive factory exhaust system.


http://www.dieselplace.com/forum/uploads/DA3_exhausts.jpg


An open exhaust helps the turbo drive the engine effortlessly.Edited by: quantum mechanic

It sounds like the CDR valve might be bad.


Mine has 195,000 miles on it and no smoke comes out if I remove the oil cap with it running.


Also, my FSD is still on the pump (moved over from last pump) and I am pretty sure it is the original one.

CDR valve? sorry, i'm new.. is there pictures of these things anywhere? what does CDR stand for?

-- Dave

Whatnot,


a 195,000 mile IP mounted fuel driver is the exception, not the rule. When it dies, will you remote mount it or take the time to mount it to the IP again?

I am not certain that it is original but it looked like it came on the old pump. I had the vin checked and the truck had no warrantee history at all. I got a lot more power and mileage when I replaced it so I don't think it had less than 60K on it.


I also got a carfax report when they had a free promotion day and the only records were owner transfers.


No, I am much too lazy to replace it on the pump but I am not planning on it dieing http://www.dieselplace.com/forum/smileys/Big Smile.gif.

CDR valve? sorry, i'm new.. is there pictures of these things anywhere? what does CDR stand for?

-- Dave


I forget what it stands for but it is instead of a PCV valve. It looks like an empty can to me but it somehow keeps a slight vacuum in the crankcase when working properly.

Crankshaft Depression Regulator maintains 2 ~ 6"wc vacuum on the crankcase to prevent oil leaks around crank seals.


Must be tested with Manometer


2" at idle, 6" full load hi boost


27"wc = 1psi


2" mercury = 1psi


A compression test will be best indication for excess blowby.


Think Crankshaft Pressure Regulator Valve is F**D's handle for the device.

I disassembled the passenger side valvecover in order to stop the flow of oil onto the turbo exhaust manifold.


http://www.dieselplace.com/forum/uploads/5ED_valves.jpg


These lobes around the head bolts leak unless you get a good seal.


http://www.dieselplace.com/forum/uploads/96C_turbo16.jpg


It took me a hour to get it all off. It would have been worse but I had the turboside exhaust manifold off two weeks ago and all the bolts turned easy. Last time I had to use a breaker bar with a cheater pipe and soak the bolts with penatrating oil.

What should the compression be?

I'm assuming you'd have to remove the injectors to do this much the same way as you'd remove the plugs on a gas engine.

is the CDR valve able to be cleaned? or is it a toss and replace type part? sounds like an over-rated catch-can PCV valve to me.. with the input before the turbo for a vacuum source. i can see how it could get clogged however :)

-- Dave

I have an Idea. It would seem that as toast as the cork valve cover gasket was that I replaced, wouldn't the positive crankcase emisson flow be lost to the vacuum of the turbo because it and the vacuum is discharging out the side of the valve gasket. The crank pressure recovery valve doesn't fail, it's wide open.


The compression should be 400 psi or more.Edited by: quantum mechanic

Compression testing can be done thru the injectors, or the glow plugs - remove all of injectors or plugs, your choice. Disconnect Fuel Solenoid. Minimum 4 revolutions per gage reading.


Normal pressure should be 380 ~ 425psi, depending on cranking speed. No less than 380psi, with lowest cylinder within 20% of highest


Most solvents will 'melt' the CDR silicone diaphragm - at 200kmi it's probably ready for replacement, tho.


It's a lo pressure hi volume regulator, dependent on air filter restriction at idle, then turbo 'draw' at higher rpm, with hi-limit of 6"wc


Mostly, it fails open - a compression check is a necessity for excess vapors from dipstick or oil fill tube.


Also, oils for gasoline engines are not suitable for Diesel service, due to much higher heat and pressure conditions in Diesel engines


Turbo temps can reach 1300deg - turbo bearings are lubricated with crankcase oil - poof!!


Will cause excess vapors, engine surge\runaway - Diesel fuel is a light oil - with no throttle-plate to limit air intake, those vapors are prime candidate for combustion.


Run a good oil\flter change thru for blowby vapor comparison


Requires CI-4, CH-4, CG-4 service.


Rotella or Delo (equiv) 10w-40 is a must.


Far as valve cover leaks -


Vacuum is a quantitative measurement of - nothing! Vacuum is lower pressure than Barometric pressure.


If 15psi (Baro) pressure in the closed crankcase is reduced by 1psi (27"wc) to 14psi, Baro pressure at 15psi will attempt to force it's way into the crankcase anywhere, any way it can.


Pressure will seek a lower level. It's the law.


Don't believe it? Remove the valve core from stem on one of your tires - see how quick that 60psi (235-85R-16's) seeks a 15psi level.


Valve cover leaks in a functional CDR closed crankcase system are result of an accumulative mass (weight) of oil being pumped into the valve covers, exerting greater pressure on a leak(s) than Baro pressure seeking 2 ~ 6"wc lower pressure - vacuum - in crankcase.


Liquid will seek a lower level. Also the law.


Could be why GM used a LARGE quantity of hi-heat black silicone RTV, rather than cork, to seal each valve cover. And pan. And timing cover. Etc. IMHO Edited by: gmctd

My wife used to have a 6.2L suburban before i met her.. she swore by rotella.. hehe so that's what i'll be getting.. :)

I saw that canister your talking about.. is there any way to check that it is infact working.. or not working..

The valve covers had liberal amounts of RTV around them.. so i guess it's been a problem for a while.

now. as i was poking around the turbo.. i noticed that the wastegate actuator doesn't seem to be spring loaded...?!? again.. i'm used to gas cars and having 7lb~20lb springs on the actuators.. becaues there is a vacuum pump i'll assume that this is "normal"

Thanks again for all the help/info.. i really appreciate it :)

That vacuum and solenoid its plumbed through are how the stock ECM keeps the waste gate closed. Any part of that system acts up and less than optimal boost will show you a fuel rich exhaust plume. I could easily blow down my CPR tube, it must be flowing.

PCM modulates vacuum to wastegate - should be 15" with 25" at the pump.


Uses the Boost sensor as feeback for 'digital regulation'.


To make a 'shade-tree' Manometer -


Get about 6' of clear 3/8" tubing


Form a 'U' with 12" legs, staple it to a piece of board with about 3" spread between legs


One 12" 'leg' will be open at top end, the other will consist of 12" leg and remainder of tubing


Space the staples at 1" intervals - do not crush the plastic tubing


Mark 0 at both 6" level staples, mark 1-2-3-4 staples down, and 1-2-3-4 staples up, both legs. This will be your column scale.


Fill 'U' tube with colored water to "0" inch level


Place open end of long tube over dipstick tube, ensuring no leaks.


N-O-T-E - keep U-tube lower than top of dipstick tube to prevent water siphoning into crankcase! N-O-T-E!!!


Crank engine, and observe water level in both legs.


Add the rise in one leg to the fall in the other leg for vacuum or pressure level measured in "inches in the water column".


If water rises one inch toward dipstick and lowers one inch in open leg, that will be 2 inches vacuum in the crankcase.


If water lowers one inch in dipstick leg, rises one inch in open leg, the crankcase has 2" blowby pressure.


Idle should be ~1", 2000rpm should be no higher than 6".


Dirty air filter increases vacuum level.


Rounding off - (14.7psi is Mean Barometric Pressure, 1 atmosphere)


27"wc = 1psi 405" wc = 15psi


2" mercury = 1psi 30" mercury = 15psi


30" mercury vacuum is 0psi


Barometric pressure and vacuum are usually measured in inches of mercury


Enjoy! http://dieselplace.com/forum/smileys/Cool.gif

http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

I guess i know what i'm doin this weekend.

Thanks guys.

It seems that the new valvecover gasket has stopped the oil leaking onto the exhaust manifold but some oil vapor(blowby) is still coming out of the dipstick tube.


I was thinking that a shutoff plate pre-turbo intake might be a good safty for runaway diesel.

Does you 93 have as much blowby?


If it doesn't, why not try swapping the CDR valves between the trucks and see if it makes a difference?

I have considered that shut-off plate, also, QM, after seeing a new P\S with less than 2kmi that ran-away on a field service job at a local oil patch.


Didn't grenade, but only because of wind shift.

I switched valves to see if it would make a difference a few months back. Didn't change a thing.


gmctd,


The cork valvecovers are the only one I've found available.

Same here - I chose black hi-temp rtv, cleaned mating surfaces with lacquer thinner, cheap at 6.95gal from homedepot or walmart.


Factoory rtv on turbo side was still fully sealed, driver's-side had light seeping above rear injector - speaks well for rtv application.

if you don't use threadlok on the valve cover bolt s they will leak within a year anyway from vibration