oil pressure light comes on randomly at idle

[ZPmadA]

I have an 86 turbo with 112,000 miles and sometimes the oil pressure light comes on randomly at idle only. I've noticed this happens on very hot days (80F or hotter). The red exclamation lights up at the same time. The oil pressure will read 0psi and the engine will still idle. If given a tiny blip in throttle, oil pressure shoots up to 2psi and light goes away. While in gear, oil pressure is at 4-5 psi and the oil pressure light never comes on while reeving above 1200 rpm. Even at 750rpm the light doesn't come on unless it is very hot outside and the car is fully warmed up. I'm not driving the vehicle until I figure this out. I'm currently using 10w40 Valvoline high mileage. I used to use 20w50 Valvoline racing and never noticed this problem.

[trivgar]

Oil pressure gauge reads in bar, not psi. 1bar = ~14.7 psi. if you had 1psi of oil pressure you'd be in trouble.

I'd switch back to the heavier weight oil.

switch to something recommended by Porsche like brad Penn. tons of oil threads recently...

[nize]

yep. you're 10w40 oil is hurting the motor. use brad penn 20w50.

[running_cold924]

brad penn huh? good stuff there. X2

[bjd34]

You can stick with Valvoline. I use the synpower 20-50 or VR1 20-50, both with ZDDP additive.

[carlege]

Any one think there could be a corellation between Using lighter weight oil and Rod bearing failure?

[running_cold924]

i'd honesty say its possible, but more for oil additives. for older engines(i say like obd 1 and earlier) you need to use the oil with the zinc/phosphorus additives. newer oils today are so bland in what they put in today, also newer engines have much tighter tolerances and require a lower viscosity oil or even a synthetic at that. older ones have much more clearance around the bearings and were not made at such a tight tolerance. but then you have to thing about what is being plugged up then(like your pcv ventilation) when the oil is a vapor and what makes sludge and such. then its to what oil brand you use....then to who's gas you run.....its just a lot of factors but the main one would be maintenance. I keep up on mine just to avoid any unnecessary headaches...

just my opinion

[choinga]

yeah - brad penn 20w-50 is the goods...very high quality oil with the ZDDP this engine needs (don't let people tell you it doesn't - it does). My PO used Valv synthetic and switching to BP solved all my weird oil pressure issues...now it's money (well, once I replace my oil pressure sender which died a couple days ago...)

[wild man]

Although I do recommend using 20W-50 oil, if the OP light starts to rear it's ugly head with 10w-40, that indicates the engine has wear. To stop the wear (obviously, you can't go back from "where" the wear is now without rebuilding), start using teflon (or other) based engine treatments with at least every other oil change. Make sure what you use claims to treat the engine, not the oil. And never go more than 5K between oil changes. Once wear starts, it continues at an accelerating rate.

[TexasBlake]

Originally Posted by nize

yep. you're 10w40 oil is hurting the motor. use brad penn 20w50.

I thought you were a strictly Mobil 1 40 weight Euro Blend guy?

[lowbob84]

So, I run Mobil 1 synthetic 10W30 for high mileage cars.. but like most people, I don't want to do anything thats going to hurt me more in the long run than help. So where would I go to purchase this Brad Penn Oil?

[running_cold924]

http://www.bradpennracing.com/ my machine shop carries it....maybe a local performance shop?