I have a 92 Buick Roadmaster with the 5.7L 350 SBC TBI injection in it.
202,736 miles on it.

I just changed the oil today, and the oil pressure sensor which hasn't been working correctly for 2 months. (fluctuated back and forth all the time)

I used Quaker state advanced durability 5w30. The car idles at 500rpm and oil pressure is less than 5psi at times when operating temp at idle.

Debated about using Lucas oil stabilizer,but have read mixed reviews about it then had a thought....

Would it be ALRIGHT to drain a couple quarts out and add the same brand oil but in 20w50??

Thanks in advance for any advice.

 

On an 93-96 lt1 that's definitely cutting it pretty close to minimum specs. I don't know what the 350 specs are.

Have you done engine modifications or dropped the oil pan?

Why aren't you looking at changing the oil pressure sensor switch? Or have you?


I did run a concoction in an old 2.8mpfi... i had like 2-3 qts of 5w30, 1 qt 50w, the rest 20w50. It did quiet the excessive bearing gaps down on the worn engine... no more bearing noise at 3k rpms... not recommending it, but as a last resort. I was always getting low oil pressure at stop lights when hot idling. First it would happen around 2000 miles a change, then kept getting sooner.

 

I have a 09 chevy Silverado 2500HD. Read no oil pressure. Replaced oil pump, still no oil pressure. Replaced sending unit and it still reads no oil pressure. Any advice?

 

If it's not knocking, you have some oil pressure. Are you measuring it from the instrument panel gauge?