From your first post I understand that your mechanic changed the main bearings and then suggested/changed the timing chain tensioner :rolleyes2:. I believe I'd find another mechanic. Sounds to me like the engine needs a rebuild. You will probably come out cheaper finding a good used engine.

Thanks, that is the kind of straight-forward answer I was hoping to get from my mechanic. I just got back from seeing him and he said that the oil pressure reading (anywhere from 1.5 to 2.5 bar) while on the highway is fine. I still get the sense that he is not telling me something.

I'm still concerned about the low pressure reading during the idle/ low RPM time while I'm stuck in traffic, though.

If I need to buy a used engine or rebuild my existing to remedy this problem, then that's what is. I am going to be looking for another mechanic who will (hopefully) just tell me like it is.

I've got an appointment later this week with a new guy I saw recommended in this forum. I'll post an update when I hear back from him.

He's not telling you that your "highway" oil pressure should be at least 3.0bar, and NOT 1.5bar. Not!

This guy is giving you some serious BS, and I would be afraid that you've been ripped off on the bearing and oil pump repairs. Sounds like a botch job and now he's dodging responsibility.

i would guess that your oil clearances are too high. this creates too large of a "leak" and lowers oil pressure. do you know if the clearances were checked when the bearings were replaced? usually with a bad pressure releif valve, you get no oil pressure. oil pressure is created when the volume of the pump is more that the "leaks" in the engine. all of the "leaks" are enginered to be a certain amount if you have a tolerance that is too high, then you get low oil pressure.

Well!
 

I thought about this last night, folks. Why did the mechanic whom I trust so much over the past 5 years charge me over 2 grand to collectively change the bearings and then the timing chain guide rail and tensioner, as well as the oil pump-- Only to look me in the face and tell me that the low oil pressure reading is no big deal?? If it was no big deal, why didn't he just tell me that before I spent all this money? I don't believe he did this on purpose, just got in over his head and is now stumped. On other simpler work he has done a fine job.

Having said that, I am going to take the car to another mechanic tonight who I see works on MB and was recommended on this site. I will post the results when I get the car back from this new mechanic because I know someone else somewhere is going to have this problem.

thanks all.

Low oil pressure?
 

So what was the solution? Thanks, Craig

low low oil pressure when hot
 

Your low oil pressure may be caused by a failed gasket between the oil filter housing and the engine block. This will allow oil to bypass directly back into the crankcase. Check it out.

This gasket failure has been previously reported on this forum

kebowers,if that is the case and oil not leaking much to affect level,can one just ignore the problem for a while.
there is no oil in the oil filter housing but oil in the crankcase.

You can't ignore it because stuff that should be getting oil under pressure is not getting it.

I mean the oil pressure sender at the oil filter housing is not getting pressure cos there is a gasket leak causing oil to go straight back to the crankcase.Does that not mean the engine is getting oil pressure which cannot be measured by the oil p sender.

I have a similar problem.Only the oil pressure goes up to 3 bar above 1500 at the tach.Idle when very hot 0.1-1.0 (mostly above 0.5)dependent on oustside temp.Mine is 180000 kms only.
Anyway at 265000 miles and worth maybe 5000 US at tradein if you buy another MB.,less if not.I think if anything major ,Leadfoot should call it quits.He's already spent more than half the car value.It seems it maybe a bottomless pit.

Low oil pressure
 

To kebowers - thanks for the gasket suggestion, that makes a lot of sense. I will check it out and get back to everyone. Craig

104 oil filter housing
 

I looked at the oil filter housing last night and it looks like it will be a ***** of a job to get it off. The upper right allen head bolt can not take a hex straight on so I will have to find one of those special ones with the swivel (rounded) ends. Well let you know how it turns out. Craig

Here's the good news...
 

I spoke with the guy who is working on the car yesterday. He works mainly on Mercedes and is familiar with them. The low oil pressure reading was the result of a dirty, clogged oil filter housing. He cleaned it up and put on a new sending unit and the reading is about one bar with the engine hot and idling.

The engine is getting adequate lubrication, on the top end. The mechanic tells me that had the engine not been getting proper oil pressure I would have been able to hear it.

Would that perhaps be the knocking noise you described? Glad to hear the problem is fixed.

Hi John,

Might have been a factor, but as the indy pointed out that there was not visible wear on the top end of the engine through the valve cover and oil was present. He says that the motor mounts are worn out and that the bearings on the cooling fan are shot, which was causing the knocking sound. Those bearings, in addition to a clogged ICV or injector,l could be causing these "knocks". I believe he meant that if the oil were not circulating the knocks would have been much more distinct than what I was observing.

thnks,
:)