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1982 240D Low oil pressure repair @ home?

Submitted by Greyerg on 24 July 2008 - 9:36am.

So my 240 has low oil pressure at hot idle. Kent's "Diesel Performance Tuning and Repair" says that this is caused by either worn oil pump gears or crank bearings.

I am currently unemployed so I'd like to try to fix this without a mechanic, but I love my car and I don't want to risk f*cking something up royally and ruining it. Would this be the kind of thing I would be able to do myself? I can already do basic stuff like changing oil and I've installed the glow plug relay manual override so I have some pretty basic experience.

I don't have a lift, only ramps, will those suffice?

How can I tell if the problem is the oil pump gears or the crank bearings? Is one harder to fix than the other?

Thanks in advance,
Grey Kingsley

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How low is low?

27 July 2008 - 11:23pm
Kent Bergsma

In order to advise will need a little more information on just how low your hot readings are and how fast pressure comes up when you accelerate the engine. Your 240D does not have an oil pressure sending unit, so I doubt it is your guage (unless of course it is leaking under the dash.

When the engine is hot and I

30 July 2008 - 9:07am
Greyerg

When the engine is hot and I put it in neutral or park and push the accelerator, the oil pressure comes up to its maximum(3) after I've pushed the pedal about 2 inches down.

Once I take my foot off the pedal, the pressure comes down to 2 and then slowly gets about 1/3 of the way to 3 and stops there.

When I'm driving and the engine is "struggling", like when I'm going up a steep hill, the oil pressure drops drastically, to around 1.

Sorry, I don't have a tach. so I can't give you specific engine rpm numbers.

How thick is your oil?

30 July 2008 - 12:14pm
Kent Bergsma

Let's rule out some basic things first before you tear into your engine.

  • What oil are you using?
  • How long has it been since you changed oil?
  • Does your oil appear thick or thin when cold (in the morning).

If your oil is getting thinned out with diesel fuel (ie bad fuel injectors, incorrect injection timing, etc) you could be diluting your oil with diesel fuel.

One other thing: Have your replaced the two very small o-rings on the end of your oil filter cap shaft?