Diesel Dilemma - PeachParts Mercedes-Benz Forum

chief_noseeum · #1 09-24-2004, 07:07 PM

Hi everybody,

I am a new member psoting for the first time. I am looking for a little advice on a problem with my 1982 300 Turbodiesel.

Recently, I was driving at 65 mph when the return line on the oil cooler ruptured spilling 6 quarts of oil. I became aware of a problem when the engine started losing power, and quickly pulled off the road.

I let the car cool down and fixed the hose and refilled the engine with 6 qts of oil. It ran fine when I restarted it, but lost power after driving at slow speed for about a mile. I noticed that the oil pressure was low as the engine lost power.

The engine starts fine when it is cold, but loses power and runs rough as it reaches operating temperature. I checked the oil and found no coolant in it. There is no oil in the coolant either. I don't think there was any damage to the head gasket as the engine temperarture remained normal through the episode.

It seems like the compression drops as the engine warms up. This seems odd to me as I would expect compression to increase as the temperature warms up if it were a ring problem. Oil pressure also drops at temperature.

Could something have happened to the valve adjustment to cause this? I know these engines are very sensitive to valve clearances.

Any ideas or suggestions?

I spoke to my local MB mechanic, but he didn't want to comment before he looked at the car. I am wondering if the engine has suffered major damage before I have the car towed to the shop as it won't make it there under it's own power.

Thanks in advance
The Chief

whunter · #2 09-25-2004, 04:54 PM

Need to think on it.
At the least, I want to follow this thread.

#3 09-25-2004, 05:26 PM

Turbo...check it.

(My 300SD did the same thing, except I noticed the gauge drop early on...I am an oil pressure monger I guess :-D)

djugurba · #4 09-25-2004, 05:34 PM

how do you know you lost 6 quarts? could take a while to re-circ oil back to everywhere it belongs, and it takes more than 6 quarts to fill 'er up... I'd drain completely, change oil filter, and refill with correct amount of oil... but you might have already tried that...
good luck...

chief_noseeum · #5 09-26-2004, 08:52 AM

Brandon,

Thanks for the suggestion to check the turbo.

What was the outcome of your turbo problem?
How did you determine that the turbo was the problem?

I will check it today by spinning the compressor turbine when it is cold and aftrer the enigne is warm. I would expect that if the turbo bearings got gunked up, they may be sticky at operating temperature.
If the turbo bearings are not damaged, I would expect that they could be cleaned up.

I'll let you know how it turns out/

Regards,
The Chief

chief_noseeum · #6 09-26-2004, 09:47 AM

I checked the turbo this morning. There doesn't seem to be a problem with it as it easily spins when the enigne is either hot or cold.

I noticed that the engine ran better than it had the last time I started it. Enigne oil pressure remained about 1.5 bar at idle at operating temperature. This is the normal pressure before the oil hose rupture. After the oil hose incident, oil pressure would fall below 1 bar at idle.

There was more smoke, especially during warm up than before. I had this before and it went away after I had the valves adjusted.

My next step is to clean out the engine with one of those oil flush treatments. Any recommedations on what type to use?

Regards,
The Chief

tangofox007 · #7 09-26-2004, 11:56 AM

Could you tell us how many miles were on your 300D? I also have an '82 300D(133,000 miles) and had been considering replacing the oil hoses to prevent a catastrophic failure such as you experienced. I suspect that hose life is more a function of age than mileage. Could a blockage in the oil system have contributed to the failure?

chief_noseeum · #8 09-26-2004, 02:37 PM

Tangofox,

My 1982 300 tubodiesel has 198,000 miles. I had replaced the oil hoses in late May becuase the old ones were leaking. I only changed the hoses between the metalic tubes and the oil cooler. I did this by cutting the old hoses then removing the metal crimps by grinding them off. I had trouble finding hoses with the same internal diameter and wall thickness and ended up using an industrial hose that was compatible with oil. I attacted each end with a regular hose clamp.
The rupture occured at the joint between the hose and the fitting on the end of the metallic tube. I may have weakened the hose at this point when I slid it onto the barbed fitting on the end of the metal line to the oil filter. Also, temperature may have been an issue.
I am looking to obtain heavier duty hoses if I can restore the enigne to original performance with an engine flush and change of oil.
Know any sources of hose?

I just purchased 5/8" ID oil resistant hose from McMaster Carr industrial supply company. I could not find any oil rated hoses at my local outlets.

tangofox007 · #9 09-26-2004, 08:24 PM

Thanks for the info. Best of luck with your engine.

chief_noseeum · #10 09-26-2004, 09:12 PM

I flushed the engine and changed the oil today. There was no change in performance. The engine is still very weak and runs roughly. I can't hear any bearing noises or other unusual sounds. Without doing a compression check, I suspect valve or piston problems. I think the engine is rebuildable since it still runs, but I don't want to go that route as I was planning to sell the car before the oil hose blew. I bought a new commuter car last April and have not been using the 300TD as much since the economics of diesel fuel are just not there.

I also want to devote more time to restoring my 74 450 SL, and the 82 300 TD was sucking up way to much of my limited free time.

Any idea of what an 82 turbodiesel is worth as a parts or project car? A friend of mine sold his 72 240 Diesel for $800, and it had severe rust problems. The body on mine is rust free as it spent the majority of its life in Florida. I have also replaced most of the wear parts on the suspension. I'd rather see someone fix it up than it end up in the crusher.

Regards,
The Chief

whunter · #11 09-26-2004, 09:36 PM

Quote:

Originally Posted by chief_noseeum

Any idea of what an 82 turbodiesel is worth as a parts or project car? A friend of mine sold his 72 240 Diesel for $800, and it had severe rust problems. The body on mine is rust free as it spent the majority of its life in Florida. I have also replaced most of the wear parts on the suspension. I'd rather see someone fix it up than it end up in the crusher.
Regards,
The Chief

There are people here who might buy it, but they will need pictures.