Buick/Olds: 1995 Buick Lesabre low oil pressure, oil pressure gauge, low oil pressure

Question
Hi,

I have a 1995 Buick Lesabre with 145,000 miles. It has been a great car to me and I have always changed the oil every three thousand miles. Recently while driving the oil pressure gauge will read at about 50 psi until the car warms up then it will lose almost all oil pressure. So far I have replaced the oil pan gasket and made sure the pickup tube for the oil pump was sealed tight. I have also replaced the oil pressure sensor. I have heard of something called an oil pressure regulator valve could this valve be stuck open and causing my problem? Also, is there anything else that I could to that might correct the situation besides rebuilding/purchasing a new motor?

Answer
Your problem requires that you install a known good external oil pressure gage on the oil system to verify the actual oil pressure.

Your most likely fault is excessive clearance of the crankshaft and main bearings.

When you had the oil pan OFF, You should have removed the oil pump and checked the internal gears of the pump as well as the oil pump drive rod that goes up into the distributor for signs of excessive wear.

I don't think I have encountered any more than a handful of faulty oil pressure regulator valves, But it IS possible. Take it apart and inspect it.



Thomas

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