My Dad's 87 Maxima seems to have low oil pressure: On cold start (70 deg F) with 10-30 oil (that needs changing) there was about 17 psi of pressure at about 800 rpm. Once warm the pressure right at the 15 psi mark at idle. At 2500 rpm it was 30 psi. Is this typical for this car? The manual says normal range is 14 to 65 psi, but the car is running at the low end of the range.

Also, there is a engine whine coming from the right (passenger) side. Are oil pumps prone to failure?

thanks

 

Yeah, the 30 psi at 2500 rpm sounds okay, I doubt any damage is being done to the engine. I'm not sure about the cold start though, as I haven't paid any attention to the gauge lately, so when I check it out tomorrow I'll let you know what kind of numbers I get. When I started it up in the winter, the gauge would go up to around 60 psi.

If you do have a problem, there could be any number of reasons why it's low. These include: low oil level, bad gauge or sending unit, thin oil, oil pressure relief spring weak or sticking, oil inlet tube and screen assembly have a restriction or air leak, excessive oil pump clearance, or excessive main, rod, or camshaft bearing clearance.

A car with a lot of miles will usually have less oil pressure than a car with fewer miles, due to the wear of the above mentioned components.

Also, from my own personal experience, the cars with V6's in them usually have a lower oil pressure than 4 bangers. I'm not sure if that's just a coincidence or if there's actually some reason for that though.

-C-

 

I should probably add that the oil level is OK, but the oil is thinned out, since its due for a change. There is no foaming or other contaminants in the oil. The car has 65K miles, but hasn't been maintained regularly. There is no rod knock to indicate bearing are completely gone, just the whine. But as you said the bearing could be worn enough to lower the pressure.

Any other typical oil pressure numbers out there?

Thanks