I have been driving my sister'* 1998 LeSabre and I think it has oil pressure issues. This car has a pressure gauge so I am able to see the pressure read-out. About a week ago I drove the car and notice the oil pressure go to around 20 psi while idling at a traffic light. I mention this to my sister and she had her son to work on the car, at my suggestion he removed the oil filter adapter and cleaned and replaced the pressure regulator. At first that seemed to help but driving the car today the oil pressure reading dropped to around 10 psi; which is getting in the danger range. It rarely went to 40 psi; mainly never above 30 psi and tended to hover around 20 psi for the most part.

One, what is the normal oil pressure for this engine?

Two, should the oil pressure remain steady as I think it should within reason?

I know that oil pressure at idle is going to be lower than when the engine is at 2000 rpm. I don't think it should go down to 20 psi, and certainly not 10; I would worry about oil starvation to the bearings.

Since the pressure regulator has been replaced; at least I was told that, then that leaves either the strainer is clogged on the oil pick-up (I had that problem on a Toyota once), the oil pump clearances are worn too far out of specs, or the main bearings are worn. Or something that does not come to my mind. Any other ideas? Any experience here?

The engine has 176184 showing on the odometer. Since my sister has own the car; for some 15 years at least, or maybe longer, the oil gets changed every 5,000 miles. I am a little concern about mine now. I only have the idiot light so no idea of the pressure. My car has way more miles on it than my sister'* car.

I had a 97 park avenue. The pressure would drop to about 8/10 psi at idle in gear. It started to knock when it dropped. I replaced the filter and the pressure came back. But unluckily for me it was too late. I blame it on the fram oil filter and i will not use them anymore. Just my preference.

The oil was changed and a new filter installed when the pressure relief valve was replaced. I don't know what brand of filter was installed; it is blue in colour is all I can see without climbing under the car.

The frams are usually orange. I would recommend to get a guage and check actually pressure. The in vehicle gauges are very inaccurate.

Yes, that would probably be wise to see just what a true pressure gauge reads and not the cheap electrical gauge in the dash. Oh, I forgot, the pressure sending unit was replaced as well.

Blue filter sounds like an STP. Yea, stay away from the Frams. Garbage.

I believe the normal operating oil pressure is between 20 and 50 psi. But that depends....

1. How long the oil has been in the engine. I personally have noticed a high increase in psi after I do an oil change. Then I will notice the psi sit around 30-40 after the oil is about 2-3 months old.

2. How hot the engine is getting. The hotter the oil, the less its able to hold pressure. Same thing with old oil. I suggest changing your oil and filter and see how the pressure changes.

I have seen several members here describe the same symptoms and I tell em to change the oil. They always come back saying the psi has increased back to normal.

I was told that the pressure relief valve was changed out, the sending unit was changed out, and new oil and filter installed.

If this is normal operation then I will stop worrying. Since I had never actually watched the oil pressure on my older LeSabre, I had nothing to go by. So I figured the LeSabre owners could tell me if everything is OK. Going down to the red line on the gauge worried me.

For an engine made in 1998 or earlier, you should have at least 37 psi at 2400 RPM. (1999 and newer, 60 psi at 1850 RPM.) That ≤1998 number seems a little low to me, but that'* what this book claims is correct.

For what it'* worth, my engine -- same as yours -- gets about 30-40 psi at idle, and about 60 psi when driving.

Thanks for the information. I found out yesterday that the pressure relief valve has not been changed, only the sending unit. I am wondering if the pressure relief valve is sticking. I drove the car yesterday and the pressure bounced around; saw it just drop from around 38 psi to a bit below 20 psi as it was being driven steadily at constant speed/rpm.

My 02 lasabre with 240,000 mi has 60psi at idle and goes up as rpms go up. I can't imagine 20 or 30 being normal.I had simular problem years ago on 57 buick.Turned out to be the oil pump had a chunk broke out of it and would not allow pressure to build. Pressure will vary some with temp but yours sounds really low.