Mercedes OM603 oil analysis leaves some concern

[colonelhogan44]

The first report for my 1987 300D came back less than perfect, raising some concern:



Looks like I have some type of wear issue going on? What could cause this level of wear metals in the oil? I have a clattery lifter or two that quiet down when the engine gets fully hot (and are getting better when cold as I drive more miles with the synthetic oil in there) but otherwise I'd think that I have a very healthy engine. I consistently get 28-30mpg and seem to have a lot of power.

I've never had any running problems other than the one issue with the engine stumbling under load with a puff of white smoke on a grade on I-5 in southern Oregon which was documented here:
http://www.peachparts.com/shopforum/dies...-along-way.html

Any ideas? any experience with these engines?

 

[JHZR2]

Is there usually Potassium and Sodium in that oil???

I dont recall, is the 603 all iron or is it iron block with an aluminum head or something like that?

 

[colonelhogan44]

It is a iron block with an aluminum head. I don't know on the sodium and potassium.

 

[userfriendly]

If it was mine I'd try Delo 400 SAE 40, which should knock the lead and iron down, with a 2% loss of fuel economy.

The 15W40 Delo CI-4 high SAPS is what I would suggest trying if the ambient is too cold for SAE 40.

What does your owner's manual say?

 

[colonelhogan44]

The owners manual states only to run SAE 40 if the temperature consistently exceeds 30C or 86F. 15w-40 is the recommended oil. I was under the impression that the 5w-40 was superior to their heavier non-synthetic brethren. The engine sounds quieter running the synthetics.

I did remember that I replaced the vacuum pump at the beginning of this OCI. It consists of an aluminum housing and a bearing that is cam driven off the injector pump timing lobes that drives a pump. It is fully engine oil lubricated. Could the break in of this pump over about 5k mikes contribute to the high iron, aluminum and nickel?

 

[colonelhogan44]

Another thing -- I am running Zerex G-05 coolant, which has no potassium, but lots of sodium per the MSDS, so I'm thinking that that I'd see high levels of sodium were there coolant getting into the oil. I was losing coolant, but I found a pretty significant leak at the radiator hose halfway through the OCI and then it has been stable.

It did have green coolant (from the PO) in it for a portion of the last OCI, however, before I flushed it as best as possible to get the correct stuff in there. It still seems that it should have correspondingly high levels of Na, though.

 

[userfriendly]

To attain a rank higher than Lt Col in Canada, an officer has to be bilingual in French and English.

Is this the first time for a synthetic in your car?
I found when switching from a vehicle that used one brand of engine oil for a long time, the engine went through an adjustment period, smelling hot and the oil turning black sooner than later.
Even switching from PCMO conventional to HDMO mono-grades exhibited this behavior.
There must be an explanation for it, perhaps one type of base oil cleans up the previous one, sweeping out all the cracks and corners.

 

[hattaresguy]

Just run it.


Was the coolant recently changed?

The only iron in a 603 is the pistons and the block, elevated iron would be the symptom of an overheat.

 

[colonelhogan44]

Originally Posted By: used_0il
Is this the first time for a synthetic in your car?
I found when switching from a vehicle that used one brand of engine oil for a long time, the engine went through an adjustment period, smelling hot and the oil turning black sooner than later.
Even switching from PCMO conventional to HDMO mono-grades exhibited this behavior.
There must be an explanation for it, perhaps one type of base oil cleans up the previous one, sweeping out all the cracks and corners.


Yes, this is the first synthetic run in the engine's history -- the PO used whatever oil the shop put in and did a lot of short trips

Originally Posted By: hattaresguy
Just run it.


Was the coolant recently changed?

The only iron in a 603 is the pistons and the block, elevated iron would be the symptom of an overheat.


The coolant was changed 1000 miles into this OCI to Zerex G-05. The 603 also has steel hydraulic lifters and cams, and some steel in the vacuum pump I mentioned.

 

[hattaresguy]

Nah tapping lifters won't cause that. A tapping lifter is just one that doesn't pump up because the little holes that oil gets in to pressurize them get restricted. I have never seen them make any sort of wear pattern on the cam because of it. They are easy enough to change and a good excuse to check the timing.

As for the vacuum pump make sure its the new style with the bolts on the cover. The smooth cover ones are a known failure point. Typical the problem with the old style is not fine metal particles its the exposed bearing failing and dumping ball bearings and metal bits into the timing chain and oil sump.

Is the EGR disabled?

That car should be fast, in tune that motor should be able to pull to 60 around 10 seconds, maybe a bit less.

 

[colonelhogan44]

Originally Posted By: hattaresguy
Nah tapping lifters won't cause that. A tapping lifter is just one that doesn't pump up because the little holes that oil gets in to pressurize them get restricted. I have never seen them make any sort of wear pattern on the cam because of it. They are easy enough to change and a good excuse to check the timing.

As for the vacuum pump make sure its the new style with the bolts on the cover. The smooth cover ones are a known failure point. Typical the problem with the old style is not fine metal particles its the exposed bearing failing and dumping ball bearings and metal bits into the timing chain and oil sump.

Is the EGR disabled?

That car should be fast, in tune that motor should be able to pull to 60 around 10 seconds, maybe a bit less.


The pump is the new style pierburg with closed bearings. I actually pulled out one that was the new style (without knowing it was -- the build code was right near the switch date so I thought better safe than sorry...)

When I bought it it would pull to 60 in about 11 seconds. I don't know what it will do now, I have done a lot of work on it. I would guess it is faster now. The EGR and ARV are disabled, but I have yet to clean out the (significant) accumulation of carbon in the intake runners. I get some black smoke on heavy throttle, so I'm thinking I'm restricted a bit.

It's a work in progress, but it is in beautiful shape. I bought it from a 90yo couple.