Arctic White 91 RS

My 'new' 91 3x Black RS convertible's oil pressure drops into the red zone and is almost zero if the car sits in traffic for a few minutes.

Details: 109,000 miles on car, fresh 5w30 Penzoil & Penzoil filter, oil is in operating range on dipstick. Car has all maintenance records since new and was well cared for by prior owner.
Water temp is about 220.

Goose the throttle and oil pressure increases to normal briefly the drops to almost zero.

Any ideas or suggestions?

Are Penzoil filters relabeled FRAM - OF - DEATH Filters?

Decided to have shop fixing the pinion seal do oil change to Mobile 1 10w30 high mileage Synthetic & Mobile 1 filter.

Comments appreciated

dmwracing42

iTrader: (3)

Oil too thin would be my guess. My race car always has low oil pressure at idle when it's hot after the oil thins out. That's a little concerning with a street car though. A heavier weight oil should read higher oil pressure.

apie2546

Possible bad oil pump. I use 10 30 here in Texas with the only oil I'll ever use Valvoline Max life (completely eliminated oil burning on cold start) but anyway I have had no issues in traffic . Always about 30 pressue

IROCThe5.7L

I'd get a mechanical gauge first to verify the stock gauge is accurate. Which it most likely is not going to be.

rusty vango

quit using Pennzoil first, and second 10-40 oil is better to use after 100,000 miles. I use Castrol GTX and have for 30+ years. it never lets me down. also I use WIX filters exclusively. IMHO Pennzoil= quacker state

UNCLE TOM

iTrader: (1)

WHY ??? why has nobody mentioned the most common cause of "indicated low oil pressure" , the sensor ? they are notorious for false readings . cheap & easy to change . with age they almost always read/indicate low . bet a cold beer that's all it is . good luck .....

Ron U.S.M.C.

Arctic White 91 RS

I can replace the OP sensor but the OP looks normal on cold start and is good in normal driving.

The OP according to the gauge is fine until the temp climbs over about 190, then the OP rapidly drops. When the car hits about 210-220 degrees then it's nearly zero.

Does that fit for a bad OP sensor?

rusty vango

hook up a mechanical oil press gauge to verify that you actually have a problem. if your oil pressure goes away then. well.... you have a problem with bearing clearances. do this ;change the oil and filter.refill with Castrol HD 40 wt oil and use a wix filter. if your oil pressure goes way up then you have verified that you need to work on the engine

Arctic White 91 RS

Shop thinks they have found at least part of the problem:

The thermostat controlled fan relay is faulty and letting the car get too hot. Sometimes the fan comes on sometimes it doesn't. The conventional oil is thinning out when the heat goes up.