Oil pressure question
07-12-2008, 12:46 PM
#1
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Oil pressure question
My oil pressure light suddenly went on while racing at Pocono last weekend. Luckily it happened right before pits in and there were no cars around. I immediately cut the engine off and coasted into the pits. Up to that point the engine had good oil pressure other that the fact that it was taking 4-6 seconds to get up to full pressure after sitting for a while.
The engine starts and runs fine now with no strange noises. Before I tear into the engine I’m trying to exclude the easy stuff. I replaced the pressure sending unit with no difference. When I crank the engine, oil oozes out of the pressure sending unit hole. Also lots of oil comes out of the oil filter mount. But absolutely no oil comes out of the OPRV hole. The OPRV (old style 3 pc) itself is bone dry. Does this point to anything? TIA
The engine starts and runs fine now with no strange noises. Before I tear into the engine I’m trying to exclude the easy stuff. I replaced the pressure sending unit with no difference. When I crank the engine, oil oozes out of the pressure sending unit hole. Also lots of oil comes out of the oil filter mount. But absolutely no oil comes out of the OPRV hole. The OPRV (old style 3 pc) itself is bone dry. Does this point to anything? TIA
07-12-2008, 03:10 PM
#2
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sounds like something is sticking- replace your oil filter- sometimes they stick- and make sure your oprv is aligned. I had my car loose oil pressure at mid ohio - pulled the oprv out, and reinstalled and its run fine since but i still need to get the alignment tool and fix it.
07-12-2008, 05:48 PM
#4
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The filter was replaced, no difference. I ordered an one-piece OPRV but they sent me one for an '87+ which doesn't fit. I have to wait until next week for that. I'm concerned that when I crank the engine there is no oil coming out the OPRV hole. Does this point to anything?
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07-13-2008, 01:38 PM
#8
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assuming your car is stock, this sounds normal. The oil got really hot (thinned)/foamed up while you were on the track and at idle speeds the engine couldn't physically build significant oil pressure. What oil were you running?
07-14-2008, 08:08 AM
#11
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are you saying after you let the car cool down and started it again it didn't have oil pressure?
07-15-2008, 12:20 AM
#13
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Speaking with a reputable tech, it appears that it is not building enough pressure to push oil through the OPRV passage but just enough to get oil up to the oil filter. Apparently it requires a fair amount of pressure to get oil to the OPRV. So I'll be ripping into it this weekend. And since I'm there, I'll be doing the rod bearing, assuming that I don't find anything terminal. Thank you all for your input.
08-04-2008, 01:16 AM
#14
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I just want to pass an update on the lost oil pressure situation.
After trying without success to remedy the situation from the outside, I finally took down the oil pan and the problem was pretty obvious. The pickup tube had sheared about 1 inch from the base.
I have no idea why it happened. No excessive vibration that I could see. Although one of the motor mounts was on its way out. It did give me a fair amount of warning in the form of slowly building up pressure when first starting. I supposed it had cracked at some point and then broke all together at Pocono’s front straight. The strange thing is that, although the tube had sheared pretty high, the pump was somehow still moving oil all the way to the filter but not enough to build up pressure.
In any case, no other harm was done as far as I could tell. I filtered to oil and there was absolutely no metal. The road bearings had been replaced a couple of seasons ago and looked fine. The Red Line race oil did its job well. I went ahead and replaced them anyway. The car is back together. Nice oil pressure right at startup. Life is good again.
After trying without success to remedy the situation from the outside, I finally took down the oil pan and the problem was pretty obvious. The pickup tube had sheared about 1 inch from the base.
I have no idea why it happened. No excessive vibration that I could see. Although one of the motor mounts was on its way out. It did give me a fair amount of warning in the form of slowly building up pressure when first starting. I supposed it had cracked at some point and then broke all together at Pocono’s front straight. The strange thing is that, although the tube had sheared pretty high, the pump was somehow still moving oil all the way to the filter but not enough to build up pressure.
In any case, no other harm was done as far as I could tell. I filtered to oil and there was absolutely no metal. The road bearings had been replaced a couple of seasons ago and looked fine. The Red Line race oil did its job well. I went ahead and replaced them anyway. The car is back together. Nice oil pressure right at startup. Life is good again.
