oil pressure problem

[94ponform]

I normally use valvoline 10w-30, but i used quaker state peak performance 10w-30 on my last change because it was on sale. since then its been having some weird pressure problems. it starts up just over 40, which is normal, then settles just below 40, which is normal. but after the car has been driven for a while, if i let of the thottle or brake the pressure drops to just above 20. and when i brake all the way to a stop, my pressure drops below 20, but stays above the red zone. is it just the oil, or is there something bigger wrong?

[krill]

Are you sure you are not low on oil? Because when braking hard to a full stop the oil may flush around in your pan and the pickup might not be able to suck in oil.

[JoeliusZ28]

Are you sure you are not low on oil? Because when braking hard to a full stop the oil may flush around in your pan and the pickup might not be able to suck in oil.
your pickup tube could be loose too.

If you think that could be possible and you have to go in there, be sure to upgrade to the "white" relief spring while youre in there. (its like a $3 part) I did it on mine and I gained a good 10 psi in most situations.

[OutCast]

I've experienced the fallen pickup tube first hand...I was able to verify that's what it was by running a strong magnet around the bottom of the pan. If it has come loose you'll hear it moving around with the magnet. It's not fun to fix so make sure it's fixed correctly.

[94ponform]

no, i don't think its low. oil is at the top of the crosshatches when the car is cold and warm. i'll have to get a magnet and check it out i guess

[krill]

Ok then it sounds like a possibility that the pickup tube fell off.

[JoeliusZ28]

have fun man - on an M6 it aint easy.

To get my oil pan out I had to dismount the engine and trans, ram them up into the cowl, and then loosen my k-member bolts to let it drop an inch before the oil pan slid out. It was the hardest part of my head/cam job this summer.

[krill]

:jest: Yea I remember my first cam swap, lowering the oilpan was absolutely the worst and most annoying part of the swap. Crawling under the car, get all kinds of shit in your eyes, getting pissed off and throwing tools around ;)

[JoeliusZ28]

yea i think i let a couple thousand swear words fly during that operation myself :jest:

[94ponform]

i watched the gauge again on my way to class, and with my foot off the throttle, the needle tends to wiggle back and forth. another sign of the pickup tube being off?

[IronOutlaw]

I bet its your pickup tube also. Mine fell off on the firebird a few months ago. It is a pain in the ass to fix. The reason they fall off so easily is b/c gm just pushes the pickup into the oil pump without any kind of screw or bolt holding it in. I tack welded mine in when i changed mine along with the oil pump to be safe.

[94ponform]

When yours fell off, did you spin a bearing at all? My dad insists that if the pickup tupe fell, i would have spun a bearing already....nothing against my old man, he knows his fair share, just not everything!

[JoeliusZ28]

why did you drop the oil pan to start with?

[94ponform]

i havn't, i havn't even done anything yet!

[OutCast]

The pump can still pickup "some" oil when the tube falls off. If you keep running it in this condition there will certainly come a time when the pump cannot reach the oil in the pan. Like under acceleration or hard braking when all of the oil tends to slosh away from the area of the pump.

[Shaggy67RS]

I normally use valvoline 10w-30, but i used quaker state peak performance 10w-30 on my last change because it was on sale. since then its been having some weird pressure problems. it starts up just over 40, which is normal, then settles just below 40, which is normal. but after the car has been driven for a while, if i let of the thottle or brake the pressure drops to just above 20. and when i brake all the way to a stop, my pressure drops below 20, but stays above the red zone. is it just the oil, or is there something bigger wrong?

I don't know, but it sounds normal to me. Oil pressure is going to be dependent on the engine RPM. When you let off of the throttle, the RPMs will go down. I think you're supposed to see about 10PSI for every 1000 RPM. So if your engine is falling down below 2000 RPM when you come to a stop (I assume it will), then it wouldn't surprise me that the PSI drops to below 20. I think mine's around 10 PSI or so sitting at an idle. It should go up to around 40 when you're cruising down the road though.

[ws6nighthawk]

I don't know, but it sounds normal to me. Oil pressure is going to be dependent on the engine RPM. When you let off of the throttle, the RPMs will go down. I think you're supposed to see about 10PSI for every 1000 RPM. So if your engine is falling down below 2000 RPM when you come to a stop (I assume it will), then it wouldn't surprise me that the PSI drops to below 20. I think mine's around 10 PSI or so sitting at an idle. It should go up to around 40 when you're cruising down the road though.

mines is exactly like that and when im cruising it is 40 and uder acceleration its in between 40 and 60.

[Tarheel'Z']

my oil pressure has always been 45-50 on the gas and 20-25 at idle and those are warmed up numbers..in all of its 70k miles of life its never seen 10 psi,,,is anybody thinking that there could be some trash in the pressure sending unit?especially since it started after an oil change??

ps,,shaggy i just "jizzed in my pants" at your sig pic