Low oil pressure

[alexhouston]

Now that I have the '90 running perfectly, I have found that the intake gets very hot. That was probably why the wires were disentigrated. The temperature guage never goes up above normal. I also found that when ideling, the guage shows NO oil pressure.

Several of my mechanic friends have told me that that is not possible since the engine runs fine and never knocks, which they assure me is the first sign of low oil pressure, even before guage sensing the problem supposedly. I will be checking pressure with a separate guage at the block soon.

I am being told the problem of the hot intake is probably the EGR valve.

Any thoughts before I pull the engine to rebuild?

Thanks

[harry yarnell]

Whoa! What's hot? Hot is relative. If the gauge is at 12 0'clock or slightly more; this is normal. As for the oil pressure, check the sensor. Just under the power steering pump.

[Richard S]

I have the same problem, Alex. Thus far I have: Replaced the pressure sensor, oil pressure relief plunger and spring, checked display, and most recently, replaced the oil pump. I have not run it yet with the new oil pump, but I don't really think that was the problem. I tend to agree with Padgett: After using some engine additive like slick 50, I may have slightly spun a cam bearing causing a blockage in the oil system. I have been running like this for several years, but I doubt the top end is getting the kind of oiling it really should have. Also, the oil is probably not doing the job of cooling it otherwise could.

[ikesleeping]

I had a 90 coupe that had low oil pressure at idle amd the two center cam bearings were spun, before pulling engine you can drop pan and look up at cam shaft.When I did I first found a lot of metal in the pan and could clearly see the two cam bearings, almost completly out of the block and riding on the cam.

[alexhouston]

It is sounding like an engine pull regardless so far. I would rather pull the engine that pull the pan and find out I need to pull the engine. 160K anyway, probably time for a refresher on bearings and rings. I want this car to be a dependable driver. Starting to look like I have a another small project now.

More input anybody?

[padgett]

That makes the fifth or sixth 90 3800 I've heard of that dropped the center cam bearings, wonder if it was a problem GM was having that year ? Ours happened at 85,000 miles and Indiana winter temperatures.. Car ran perfectly without a sound just light on at idle and 19 psi indicated at 2000.

Drove home from Indiana to Florida by way of Gatlinburg, over 1,000 miles at Interstate speeds after Indiana dealer kept for a morning and said it was the gauge. Never missed a beat but when dropped pan at home, one bearing was in pan and other was circling the cam. Could not find oversized cam bearings so replaced the long block. Still have the original block.

[Guest crtnrds]

Anyone ever try a higher output oil pump or beefing up a stock one?

[padgett]

Oil related problems are very unusual on a 3800, there just seem to have been a run in mid-1990 specifically that had something wrong with the cam bearings. What month was your 90 built in ? Think ours was a May car.

[harry yarnell]

Pumps are fine on 3800's. Being CRANK driven/mounted, there's no way you can put a bigger pump in like the days of cam/dist. driven pumps.

[Richard S]

Alex, 160K is really nothing with these motors. Since dropping the pan is not more than getting a new gasket and taking out some readily accessible bolts, there is every reason to check. As I say, I have been running mine for at least two years like this. If a long block is going to be necessary, I don't see much reason to pull the engine until something obvious and serious starts to happen. I haven't looked, but it is possible that the cam bearings torqued a little so the oil holes no longer align, but the bearings are still in the bores. The other posters actually had their bearings spin right out of the bore. Seems like that would set up quite a racket? I'm not sure I'd take my car cross country or do the San Diego to Vegas run mid summer, but other than that it has been very dependable around town despite the low pressure.

[Guest F14CRAZY]

This is interesting.

[Guest crtnrds]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Pumps are fine on 3800's. Being CRANK driven/mounted, there's no way you can put a bigger pump in like the days of cam/dist. driven pumps. </div></div> Thanks, Harry.

Are there no springs or anything that can go bad/stretch or am I living in a time warp?

[harry yarnell]

Well, yes, there's the pressure reg. spring and plunger in the oil filter housing, but at the pump, there's just the two gears. Being crank driven, you get twice the pump speed over distributor driven pumps.

[Guest crtnrds]

My '88 w/the '96 Riviera S/C motor has low (9-10lbs.) oil preasure when hot (200+) at idle. Goes to 40 or so at speed. Don't know if it is a similar problem or what yet. First I'll check the sending unit & electronic guage. Guess I can eliminate the pump as the problem? I'll probably just thrash it til it quits since it runs good & no knocks or other tell-tail noises.

[Richard S]

Frankly, I think where a spun or "torqued" cam bearing is the issue, the oil pressure will be low or non-existent at idle, and not improve much at high rpm. If you can get it to stay a 40 lbs/ at cruising, I don't think the cam bearing is the issue. Is there is a hole in the cam bearing that is supposed to align with the galleyway in the block?