Engine/Transmission (1994 - 1998) Oil Consumption Rings, Head, or Turbo?

[JHastings]

Hey all, got a question. Pickup is burning pretty good amounts of oil these days. i'd say somewhere in the vicinity of 3 quarts per 1000 miles or so. I have a buddy's turbo on there after taking off my twins that came from who knows where but doesn't seem to have too much play in it. Not totally sure, but seems like it's burning a lot more oil since the twins came off.



There is gray haze on start up and maybe all the time (Just tougher to tell when you are running). Drips only slightly out of blowby tube overnight and doesn't make a huge mess under the truck or anything.



How can I tell whether it is my rings, valve seals, or maybe (hopefully) the turbo burning the oil?



If it comes down to the head or rings can you tell without taking the head off?



Leak down, compression test...



TIA



Jamie

 

[GOlsen]

I know when my oil drain tube off the turbo was blocked, I ended up losing oil and had a haze. I would recommend checking it out first, could be an easy fix.

 

[CBlack]

I had a similar leak and it turned out to be the valve seals. About $35 later and some seals from Cummins Midsouth and it's fixed.

 

[JHastings]

How did you determine valve seals or did you just replace them and it fixed it? I should be able to do it with the head on right? Put each cyl at TDC and replace?

 

[CBlack]

I think I should clarify... valve cover seals (gaskets).

For that there was a lot of built up gunk around the top. No oil coming from elsewhere. I cleaned the area thoroughly then replaced them. I cleaned it again afterwards. I've driven it over 1000mi and it's still clean. And no oily residue elsewhere.

 

[JHastings]

oh gotcha. im thinking valve stem seals.

 

[JHastings]

checked the turbo drain line, its wide open and free. Also checked my two rear valve cover seals, they were weaping a little, but hardly at all. THere is some oil on the fron of the motor, but doesn't seem like enough external oil to make up for teh quarts of oil that I am adding every week. Anybody have a compression testing kit that they rent or want to sell?

 

[JHastings]

I will also add that the pickup doesnt drip oil overnight and when its running it doesnt blow out the blow by tube excessively even with the exhaust brake on. The tail pipe does however have a fair amount of soot in it and it blows some pretty good gray haze. How can you tell if it is a bad turbo?

Jamie

 

[Mhannink]

well check the boost side of the turbo. if you have oil anywhere on the pressure side say going into the intercooler or into the engine its probably the turbo. next check the radiator if you see oil in there its a head problem though no oil does not eliminate it. rings would show lots of blow by which it doesnt seem you have. and valve stem seals would be hard to determine without just doing it and seeing the difference.

 

[GOlsen]

When my turbo was blowing oil out through the exhaust, the smoke was more white than grey. Also inside the tailpipe wasn't just soot, there was oil in there too.

 

[JHastings]

Cold side of the turbo is dry and there is no oil. As for the hot side, I don't see any oil at the tail pipe or at any other point in the exhaust (ex brake... ).

So I guess if it were valve stem seals, I should just get a spring compressor and get after it? Anybody ever done them? Part Numbers? Sounds like maybe there are two types one for the intake valves and one for the ex valves? Also heard that maybe some people are using a later style valve stem seal on the 12 valves?


Thanks,
Jamie

 

[GOlsen]

I've never done it with the head on the truck. I imagine you could do it just like replacing the valve springs with bringing the piston up to TDC and change them out. As far as the valve seals themselves, from what I've seen there's an old style and a new style. The new style seals are shaped like a top hat and are held down by the valve springs. This style requires machining to work, so stick with the old style seals. The seals themselves are the same for intake and exhaust IIRC.

Here's a link for the old style seals:
12x 5. 9L 12 Valve Dodge Cummins Valve Seals 3921640

 

[GOlsen]

Upon doing some more looking, I see that some of the later 12 valves used the new style seals. Cummins should be able to tell you what part number you need with the ESN.

New Style: 3957912
Old Style: 3921640

 

[JHastings]

Cool. Thanks for that. I'll check and see what type I have.

jamie

 

[JHastings]

Also guessing I will obviously have to remove the nuts on the studs that hold the rockers. Any advice on re-torque? They are 12mm ARP

 

[GAmes]

You not only have to remove the small bolts, you have to remove a headbolt for each pedastal. I don't remember the tq offhand, but you need a FSM anyway.



I have replaced the valve seals with the engine in the truck. I was using a qt every 800 miles or so, and the seals were a last resort. I had about 770k on it at the time. The job is an all day sucker. I gave up on the spring compressor from Genos and bought one from NAPA that works lots better. part# 3271 I recommend you start at #6 and work forward, easier on the back. Also be sure to clean the little towers completely of oil before tapping the new one down (I used a deep socket). If you don't the valves will lift some of the seals off and you will have to take it apart again (don't ask). The job turned out to be an exercise in futility and I swapped engines. One of these days I'll get to tearing down the old one to see what is worn out.