Please, anyone, I'm desperate. 8 weeks and I still aint got it figured out. 79 240d with way too much oil pressure. So much oil pressure that it keeps popping the o-ring out the side of the filter canister. I have changed the o ring, the filter, even changed the filter canister, all to no avail. Dropped the pan and checked the oil pressure relief valve, it's tweaked to the side (see picture), apperantly too much clearance between piston and cylinder. I put it back in it's place and it worked for a day, took the pan down again and i've got the same problem. If that valve sticks where the piston will not go back into the cylinder, is that too much or too little oil pressure? Is that likely the problem or is it a symptom of the problem? If that is the problem, does anyone know where I can buy just the valve or do I need a whole new pump? Anyone have valve or pump for sale? Got money that I'm ready to spend to get the car working again.

Thanks,

Jason

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did you check with phil on fastlane aboout getting a new valve?

i am not sure this is what you need, i have never heard of this problem before. are you sure yoiu have the right o ring on the filter housing? what brand of filters are you using? how many times has it blown out?

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

have tried mann and mahle filters with the respective o-rings. Pushing half a dozen times it's popped the o-ring out.

For the time and energy you have invested, try installing a new pump? It seems to me that if you are having problems with the pressure relief valve sticking then the logical approach would be a pump replacement. The cost effective approach might be to clean and or deburr the relief valve bore------

You need the Selecter: http://www.geocities.com/braunovi/Selecter/SelecterD1980TooMuchP.htm

Pressure is usually caused by something clogging the oil path, as in sludge. I would verify all passages are clear. Chances are your bearings are oil starved, so I wouldn't drive it until it's figured out.

The positive displacement pump is not likely to fail and generate a higher pressure.

Before identifying the pump or relief valve as the clulprit, you need to check the pressure. The dashboard gauge tops out at 3, and as it's normal to run with it pegged, it's not up to the job.

You'll need to find an adaptor that will go into the block or at the gauge end of the oil pressure gauge line, and use a gauge with a higher limit.

You could have a warped oil filter housing.

[QUOTE=Hirnbeiss]
Pressure is usually caused by something clogging the oil path, as in sludge. I would verify all passages are clear. Chances are your bearings are oil starved, so I wouldn't drive it until it's figured out. QUOTE]

I have had the oil filter canister off and could blow air through one of the holes in the block, could hear the air through the oil fill. The other hole into the block, I could not blow any air, but I understand this is normal. The only thing not starved for oil is my driveway.

I have a guage, just not the correct fitting. I am fairly sure, though not positive that the filter housing is fine. I am on the second filter housing with the same problem. The only thing that I can find common with is happening more than once is the relief valve (see the pic above). This thing is tweaked whe I pull it out. Does anyone know how that relief valve works? With it stuck in that position (see pic above) is it allowing more pressure, or less, it has to be one or the other. If it causes more, then it is likely that is my problem, if it causes less then it is only a symptom.

I suggest you post about this in the Diesel Discussion forum. Many members don't leave that forum and have MUCH knowledge about these engines. Someone's probably run across this before or knows how to fix it in there

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on the 601. Since pressure at 3000 rpm should reach 3 bar, and at idle 0.3 bar, the relief valve shouldn't open until you are well north of 4000 rpm.

If the problem started after a good rev session, maybe the relief valve is the culprit. It could have opened, and then got stuck shut in such a way as to stop relieving pressure. Hopefully they don't use relief valves of this design on nuclear power plants. Actually, on the picture I see from the 601, they have a guide pin under the piston that looks like it should prevent the piston from getting cocked like yours.

In any case, I think your most effective course of action now is to replace the relief valve. You already have the oil pan off. I don't know if the valve is sold separately, but the pump looks like it includes a new one, and costs $169.