Valve Stem Seals Didn't Cure Smoking, What Next? - PeachParts Mercedes-Benz Forum

MSGGrunt · #1 06-28-2014, 08:37 PM

I know smoking diesel questions are probably as common as what is the best oil or best tires but, I ask as I know experts on here can hopefully lead in the right direction.

My car is a 1982 300SD with 122,535 miles. New Bosch injectors, did a diesel purge, new valve stem seals and adjusted valves. I have not done a compression test as I need to get to correct size fitting for my gauge.

The issue is a constant smoking problem that from the pictures I can assume is oil and not coolant. It smokes all the time and more with added throttle.

My questions are, with the amount of oil in the exhaust is this from bad turbo seals? (I have a kit to rebuild the turbo) Worn valve guides? Worn piston rings? Something else?

ROLLGUY · #2 06-28-2014, 08:54 PM

I don't believe that worn valve seals on a turbo engine can cause smoking. The manifold pressure won't allow oil to get through. However, it might be the other way around in that worn valve stem seals would cause more crankcase pressure (blow-by). Excessive blow-by is a cause of constant oil burning. I would also look to the turbo seals for the burning oil, as it is another logical place for oil to get in the intake tract........Rich

MSGGrunt · #3 06-28-2014, 09:43 PM

My oil cap doesn't "dance" on the valve cover like some videos I have seen but, this probably doesn't tell how much blow-by I have.

I can rebuild the turbo... No Problem...
I'll have the head rebuilt if I have to...

But, if the rings are worn and the motor need to be rebuilt that is a whole different story. With 122,000 miles I would hope my diesel hasn't seen a hard life and worn out already.

Diesel911 · #4 06-28-2014, 10:11 PM

I have about double your 122,535 miles on the Engine. So I think unless one of the Former owners teribbly abuse it or over heated it or WVO ed it there the Piston, Rings, and Cylinders are likely OK.
Stuck Piston Rings can happen if the Car sat for a long time, Car driven with a Coolant Tmermostat opening to soon or entirly removed or other things that would cause excessive Carbon Build up in the Engine.

Putting something like Marvel Mystery Oil into the Cylinders and letting it soak a week or more in there might loosen them if that is the problem. It has been said that switching to using Synthetic Oil dose the same but takes 200-300 miles of driving.

If the Turbo Seal is leaking on the Exhaust side if you remove the Parts between the Turbo and the Exhaust Pipe you can look inside the Turbo. If the Carbon is nice and shiny wet looking Oil has been getting in there.

If you remove the Turbo Charger and see that wet shiny Carbon in the Exhast Manifold the Oil is coming out of the Engine.

It is possible for Oil to come of the Compressor side of the Turbo and make it into the Engine but it is hard to tell due to the Oil Mist from the Blow-by and it is a long way for the Oil to travel upwards and down the Mainfold so that is less likely.
It sort of depends on how much Oil you find inside of the Turbo Compressor Housing.

If Oil is getting up into the Cylinders sometimes the Precombustion Chamber will exibit that shiny wet Carbon look.

MSGGrunt · #5 06-29-2014, 07:53 AM

I have what I would call a lot of oil coming from the exhaust side of the motor. The exhaust ports are black wet and shiny as is the exhaust side of the turbo and turbo down pipe. With the constant smoking and the amount of oil in the exhaust track my next question is, where is the oil coming from that is getting into the exhaust?

MSGGrunt · #6 06-29-2014, 08:10 AM

I have removed the turbo from the exhaust manifold, removed the intake and exhaust manifolds from the motor and will be rebuilding the turbo as insurance if nothing else. I just don't want to go through all the work of rebuilding the turbo, cleaning the manifolds, buying a new intake/exhaust gasket, taking the time to install everything only to find that my problem wasn't solved. I know I have to baseline the motor with a compression test and maybe a leak-down test to assess worn valves/valve guides or rings but, oil is the exhaust passages of the head, turbo and down pipe, what is that a sign of?

If valves and guides I'll rebuild the head.
If rings I'll have to figure out what I want to do.

Silber Adler · #7 06-29-2014, 09:56 AM

Have you measured compression?

How does it drive, what is the oil consumption?

Silber Adler · #8 06-29-2014, 09:57 AM

Are your fuel injectors set up well?

rscurtis · #9 06-29-2014, 10:47 AM

Your exhaust looks like it's burning clean. The oil in the turbo is most likely leaking into the turbine side from one of the seals. If it was burning in the engine, the ports would be full of oil too.

MSGGrunt · #10 06-29-2014, 08:08 PM

Not sure about setting up the injectors or even how to do it. I do know they are brand new.

I haven't tested the compression yet as my compression test gauge has small adapters designed for spark plug engines. Where would I get the right adapter that fits in the OM617 injector hole?

I don't have a lot of info to go on as to how it drives. Immediately after buying it I put it in the body shop and started a mild restoration/refreshing of the car. I only drove it probably 150 miles.

Agreed, the engine exhaust ports look like they should, but what about the oily intake ports? and all the oil in the turbo exhaust and down-pipe? Leaking turbo?

I guess my top priority to assess what needs rebuilding is a compression test.

Silber Adler · #11 06-29-2014, 08:28 PM

My car had a leaking egr. Wetting and mucking up the intake.

Harbor Freight has a pressure gauge that can fit either the glow plug or injectors.

You should adjust the valves before checking.

If the injectors are not spraying well I could imagine increased smoke. They should be pop tested and inspected for a good spray pattern. Member greazzer does a good job.

ROLLGUY · #12 06-30-2014, 01:05 AM

Quote:

Originally Posted by Silber Adler

My car had a leaking egr. Wetting and mucking up the intake.

Harbor Freight has a pressure gauge that can fit either the glow plug or injectors.

You should adjust the valves before checking.

If the injectors are not spraying well I could imagine increased smoke. They should be pop tested and inspected for a good spray pattern. Member greazzer does a good job.

The best fix for a bad EGR is a block off plate kit. Check out my signature. And yes, greezer does a great job with injectors...Rich

cooljjay · #13 06-30-2014, 02:29 AM

If this car only has 122k on it, and you've only driven it 150 miles since buying it....I wouldn't be doing all this work.....

Block off the egr.....take this car out for a very long freeway drive, drive it hard....keep driving it like a car and not a grocery cart as it was preciously used....then see if things clear up...

OM617YOTA · #14 06-30-2014, 09:19 AM

Just another +1 for Greazzer - he did amazing work on my injectors and went WAY above and beyond with customer service.

rscurtis · #15 06-30-2014, 10:14 AM

Don't be obsessed with checking compression, it's not your problem. If the car starts OK and doesn't have a lot of blowby, don't worry about it. I've been working on engines for almost 60 years and I don't even own a compression tester.