Oil pressure inconsistency

[LwnGy83]

the oil pressure in my 97 3.8 m5 has been acting, in my opinion, wierd. When it's cold or just started up the pressure gauge says it about 90 psi, then afte awhile, when I'm idling after running it abit, it drops down to about alil above 30, but when I hit the gas it goes back up to almost 90. I don't know if this is a problem or just something that it does... anything would help, thanks guys.

[Need4Camaro]

Normal... As your car heats up the oil thins out thus giving you lower oil preasure and when you step on the gas the pump just pumps it faster bringing it back to 90. When your car cools down the oil thickens again so when you start it up again you're once again running thick oil giving you the higher idle preasure.

Unless your car's running bad, don't worry about it.

[Turbo V6 Camaro]

umm i have a high oil PSI kit and my oil PSI never hits 90 PSI.... [img]graemlins/stickpoke.gif[/img] that sounds kinda high to me

what oil you useing

[LwnGy83]

I'm using a Mobil 1 full synthetic, 10W-30. It seems alil high to me too. The thing is, that it wasn't always running that high. About 6 months ago the normal psi was about 60, and I changed my oil one time and it shot up, and another thing is that when it's idling it's idling around 45psi, not 30 like I had originally said, it's running alil rough... So I don't know what's going on, I just thought I'd run it by you guys and see what you came up w/. Thanks guys.

[Turbo V6 Camaro]

cuase i only hit 80 PSI at WOT and i have that kit

you might have a week spring in th OPSI regulator

[gergwheel]

I have the exact same problem as lwngy83. my theory is that if the oil pressure isnt low then there isnt anything wrong. but lately i have kinda worried about it, and i thought about changing the oil pump out, but i cant decide because again, it isnt low.

[LwnGy83]

How hard is it to replace the OPSI regulator? And how hard is it to replace the oil pump itself?

[Need4Camaro]

I meant 60 not 90 in my other post, yeah like viper said 90 is pretty high.

Speaking of Oil, I used "6 cylendar restore" from Advanced Auto with Castrol Oil from Walmart, then on my next oil change I put in some Lucas Oil Stabilizer and Castrol Oil... I noticed a good increase in Oil Preasure and it takes alot longer for the oil preasure to drop aswell!

[Dominic]

probably just a sensor problem/. Buy and try a new oil pressure sending sensor (next to the oil filter)

[dafirebird]

My oil psi is @ about 40 idle, 60-70 psi freeway. Is it true if it gets too high it'll start blowin' seals, piston rings (blow-by)??

[Rob Bell]

You may want to hook up a mechanical oil pressure guage and see if it gives the same readings. If not, then you know it's a sensor. Otherwise then you should look into fixing it. I don't know how high "too high" is...maybe 90 PSI isn't a problem. But if it gets too high the filter will explode, and then you'll really have a big mess.

[LwnGy83]

Hey Guys,
Well... I think I found half the problem. My oil pressure sending unit (sensor) started leaking big time, so I replaced that and my oil pressure isn't so inconsistant. When I start cold the pressure is near 90 psi then after awhile it gets warm, it's around 60psi when idling and when accelorating it goes up to around 80 now. It's definatly an improvement over what was happening (going from 90 to almost 30) Someone though that the problem was probably the oil pressure regulator valve (or by pass valve as the dealership calls it) and/or spring. I'll probably talk to my mechanic and see if that's what he thinks and I'll probably replace it... 90 seems high to me, but how high is too high...? So... I have an interesting problem. Thanks guys

[Pewter99Camaro]

If i remember correctly from when I still had mine, my 99 3.8 m5 was consistently around 60.

[BLLDOGG]

90 is still too high. mine never leaves the 60 area. you may have fixed half the problem but im wounding if the problem caused that oil leak :\

[BLLDOGG]

90 is still too high. mine never leaves the 60 area. you may have fixed half the problem but im wounding if the problem caused that oil leak :\