Headscratcher for you

Slam · 01-06-2005, 01:14 PM

Guys, here's an interesting problem,

Resealed my oil cooler in the fall and car developed the following symptoms. Ran fine until one chilly morning after a warm day previously, it registered very low oil pressure (idiot light on too). I took the oil cooler apart, checked it and reinstalled it. Car ran fine for about a month or so, then the same problem developed. One chilly morning I had very little oil pressure.

Would a drastic change in ambient temp be able to affect the alignment of the relief valve if I didn't get it just right in the first place? I'm talking about the engine reaching operating temp in the evening, being driven and then parked just before bedtime on a cool/cold evening.

To make things even more interesting, after I'd parked the car for the winter I went out to the shop and started it on a whim. This was about a month after the above mentioned problem. Guess what? Oil pressure was fine. Took the car for a quick drive and it behaved well. Put the car away, turned on the shop furnace to keep everything from freezing (about 10 C). Next day, no oil pressure.

I'd been planning on doing an engine rebuild after spending some time on this website and asking a few questions (BTW - thanks everyone for the help and the info - great bunch of people). But maybe I can get away with just doing the oil cooler again but being twice as anal and making sure I do it perfectly...

Slam
1983 944 - my "PITA"
1982 931 - her project

ae1969 · 01-06-2005, 01:27 PM

I am assuming you are still running the old OPRV. Replace it and the problem will go away.

Slam · 01-06-2005, 02:49 PM

Yup, I'm using the old OPRV. At the time I'd initially done the job I had some milkshake on my dipstick but an oil change cleared it up. I think the seals held but the valve was misaligned. If I have indeed had mixing, how much mixing would warrant an engine teardown? It runs fine - there's no bearing noise in the bottom end.

Thanks for the tip - I'll see what that fix does.

Slam
1983 944
1982 931

strath44 · strath44's Garage

could the sender unit be at fault causing these symptoms ie removing the oil cooler worsened a bad wire etc?

Slam · 01-06-2005, 04:21 PM

Hiya,

Nope - sender's good. It was the lifter clatter that clued me into it the first time it happened. You know - get up early in the a.m., go and start car in a mind-fog, don't check gauges. NExt thing I know I can hear the lifters, and the idiot light glow coupled with the gauge confirmed my suspicions.

Thanks, though.

Slam
1983 944
1982 931

Britwrench · 01-06-2005, 06:56 PM

Did you check that the crank pulley bolt was tight, it's a reason for low oil pressure. The other thing is did you use the aligning tool when refitting the oil cooler housing?

Slam · 01-06-2005, 09:54 PM

Crank pulley is okay. Hasn't been off in years - I modified my inner timing cover so I could change belts without having to remove the crank pulley. Of course, that doesn't mean it's tight enough, it just means it hasn't been checked in a while and in that while it hasn't noticably moved. Except for rotation...and when the car moves...where was I?

Alignment tool? Ah...um...well, you see, it was like this... I reassembled the thing as a unit. You know, "Now bolt housing A to block B while holding your pinky and the seal in alignment with valve C ensuring valve C doesn't slip off spring D while threading bolts E thru H making sure C is free to move... And keep the cat out of the coolant."

Frankly I won't mind springing for it (the alignment tool) and a new OPRV now I have the time to tinker with the car.

Thanks,

Slam
1983 944 - My "PITA"
1982 931 - her project