Hi,
I have a 93 Volvo 240 that has almost 0 psi oil pressure at idle and only about 20 psi when cruising when the engine is warm. Two years ago when I first discovered this problem, I changed the oil pump (and o-rings) and main and rod bearings except for the last thrust bearing because I couldn't get it out without removing the crank. I measured all of the bearings with plastigauge before and after and they were all in spec both before and after. The old o-rings were also OK. When I put it together with all the new parts there was no change. Since then (20K miles) it has slowly gotten worse. The engine still runs quiet. Where is the pressure being lost? Since I changed the bearings, I doubt it is there. The pressure is usually higher when the car is cold and has fresh oil but not 80 psi anymore like it used to be when cold. When the car is hot, the oil thins out and the pressure drops. I was using 10W40 and am now using 20W50 and it is slightly better with the thicker oil. I checked the camshaft and there are no bearings, just bearing caps and they also measure in spec. When the engine warm and idling and the pressure is reading 0 there is plenty of oil flooding the camshaft. At first I thought that too much oil was flooding the camshaft, but today I examined my other 88 Volvo 240 and when the engine is hot and idling, I can also see plenty of oil flooding the camshaft through the oil filler cap. I also put the oil light back and put that very same gauge in my 88. When the 88 is hot or cold the oil pressure is consistently reading 80 psi, and at idle it drops to 75. Interestingly, the oil light in the 93 only intermittently flashes at idle (like when the AC cycles) and is off when driving. If I never checked the pressure, I guess we would have been driving this car until it got so bad that it would be very noisy (too late then). Have any of you mechanics out there completely disassembled a "redblock" engine have any ideas about this specific problem? I have rebuilt '60s engines in the past and they are quite simple. What is different in this block from Ford or Chevy '60s 6-cyl engines? Since everything appears to be correct, I fear that after I go through the work and expense of rebuilding this engine, I will not find out where the pressure is going and not find out until after it is reassembled and put back in the car that I still have the same problem.

Another question is what is the easiest way to remove the oil pan? The last time I did it, I had to remove the steering coupler, the exhaust, the drive shaft, the motor mounts, and then support the engine from the top with a large piece of wood across the fenders while I removed the four bolts that mount the cross member to the body and then pressed the cross member and the suspension down. There wasn't much room to work. Is there an easier way to do this? The Bentley book simply says "remove the cross member". Am I missing something? Is there an easier way to do this? I do not have a lift and everything I do is on jacks in my garage.

I haven't decided what I want to do yet. I can get a 90 engine to replace it from friend, but I'm not sure if it is compatible (I posted that in another thread here). I could also let someone else rebuild it, but if everything so far has checked out OK, he might not fix the problem either and then I'll have to haggle about whether I should pay him or not. I could keep gathering information and rebuild it myself at a later date. Perhaps I don't need to completely re-install it when I'm through so I can idle it for 1/2 hour until it's nice and hot and see if the pressure stays at 80 psi before I complete the job. I probably won't have the time to do anything myself until next spring, but as soon as my wife's new car comes in, I can stop driving it until then. Maybe one of you guys have seen this problem before and there is an easy fix that I missed or at least an easy test that I could do that will show me exactly what is wrong. Thanks to everyone in advance.

HG