EJ-22 Low oil pressure at idle only

[guy123]

1996 Legacy L wagon 4eat, EJ-22. I have about 175,000 miles on the car now, and I just installed an oil pressure gauge- wish I had done it sooner. Anyway, the gauge is an electric Sunpro gauge, so not very precise. I tested the pressure today with a mechanical gauge to get some more precise numbers.

 

With the oil at operating temp, I measured 9-10 psi at 700rpm idle, 22-23 psi at 1500rpm, 30 psi at 2000 rpm, and about 40 psi at 2500. Not sure how accurate the mechanical gauge is, but I was hoping it was better than the electric one.

 

With good pressure at higher RPM, am I correct to assume that the low psi at idle is probably due to normal wear in the engine at this mileage? The oil pump is original, never replaced or serviced. I've been running 10W-30 since I bought the car at 110K, should I run something thicker? Or is this psi reasonable for the engine given it's age? Any thoughts you guys have would be awesome, thanks in advance.

[porcupine73]

Why would you assume that? The spec at idle is something like 14psig but that can also depend on what weight engine oil you used. And the sunpro isn't going to be as accurate as some scientific instrument, especially not an electric gauge. So it sounds about right to me.

[ivans imports]

the preshure at high rpms is erelavent what maters is how long it takes to get preshure exactly. and how mutch preshure when hot at idle min 10 psi hot at lowest idle if less than that berrings are on there way out. I time the oil light on the first start cold and see how long it takes a good engine takes 1/4 second a bad engine takes 1-2 seconds for light to go out and any knocking on startup is bad

[guy123]

Thanks for the responses. The idiot light on the dash goes off almost instantly when the car is started, so the oil pressure is building at a good rate. The readings I took were what the mechanical gauge showed, not what the sunpro shows. I realize that I'm probably splitting hairs here, I just want to do whatever I can to keep the car running for as long as possible. I guess I won't worry about the 9-10 psi at idle.

[Fairtax4me]

Maybe a bit low but nothing I would worry about. Spec is 12psi at 700rpm hot.

 

There is an issue with the back plate on the oil pump coming loose sometimes. The screws that hold it on loosen and it lets oil pressure bleed off back into the crankcase. Doesn't sound like that's an issue in your case, but its worth checking at your next timing belt change.