I have a 1987 gmc suburban and the oil pressure gauge at start up reads about 35 to 40 but after driving a while will drop to 15 is oil pressure switch bad
It depends on your mileage. It's normal for the pressure to read high on start up and then drop some but your numbers are a little low on start up, usually on the high side of 40-45.You could check your pressure with another guage and see if it reads any different. If it does then you should change yours. But if your mileage is running on the high side of 200,000 then it's probably wear and tear. I would be inclined to try a heavier oil, 15-40 or 20-50. This should bring the pressure up and help with lubrication. You could also add something like Lucas to your oil to help with lubrication and pressure. It's also possible the oil pump is wearing out but unless the mileage is below 150,000 it likely won't do much good and a new pump won't like the heavier oil.
If you are unsure of the mileage you could do a compression check. If it's 100 or under the engine is worn.There is still life in it as long as the numbers are close together but it is time to start thinking about the next step.
Jun 12, 2011 |
1987 GMC Suburban