Player87

iTrader: (1)

Hi,
I have a problem with the oil pressure of my 1998 Trans AM.

2 weeks ago when I drove my car I recognized, that the oil pressure is not at 40 like normal. No it was around 25. Only when I accelerated the oil pressure went back to 40.

Before this was not like this. The oil pressure was at 40PSI when I drove normal.

Yesterday I drove my car for 50 Minutes.
When I started the engine the oil pressure was at 40
20 minutes later: oil pressure maybe 35
30 minutes later: oil pressure at 25
there it stayed till the end of my test drive.

I am using an 5W40 oil. The oil is 15 months old (but just 6000mls old).

I think with a 5W50 oil I can get more oil pressure, but is it possible to use this in our cars?

The car is only used in summer time.

Please tell me what i can do to get my oil pressure back at 40

ZDOG

iTrader: (13)

start with an oil change. 15 months is a long time. it gets filled with contaminants, like water and fuel. it could be or have been eating at your bearings.

milage isnt a problem but that time frame is really long between changes. try a mechanical guage first to verify. heavier oil will just mask the problem.

good luck

Player87

iTrader: (1)

ok so i will try it with an oil change using a 5w40 oil

Zitty'sZ

iTrader: (29)

How many miles are on the car ? The 1998 - mid 2000 engines came with oil pumps that start to lose oil pressure around 50,000 miles or so . I think it had something to do with the bypass valves in the oil pump hanging open or something like that causing the pressure to drop . My car is a 1999 and it did just as yours is doing, so I changed the oil pump when I did my cam install and now it idles at 65-70 cold and 40-45 hot . Don't use heavier oil to make the pressure come up, as stated before , that just masks the problem . Change your oil and use either 10w-30 or 5w-30 and see what happens . If it does not change the problem I would change out the oil pump and cam and timing chain while you are in there !

Player87

iTrader: (1)

my car has 86000 mls on it.

is there a way to check if my oil pump is working correct or can i check if there is a small damage?

How much are the new parts i would need?

THX

CALL911

iTrader: (17)

Zitty is correct in that the 98 LS1's had oil pumps that were notorious for going out prematurely. Its obviously working, or you would show virtually no oil pressure. It could be a sign though that it is on its way out. This could also be a sending unit going bad, but since its a 98, I would guess it's the oil pump.

First things first, do an oil change, and change the oil filter to a good AC delco, or Mobil 1. When I first got my 98 Formula it was also reading low oil pressure, but after changing the oil and Fram oil filter for a Mobil 1 oil filter, my oil pressure went back up to normal.

I recently did a bit of work to my Formula (heads, cam, intake, ect.), and when I did it, I swapped the factory 98 oil pump for an LS6 oil pump. Now my oil pressure is MUCH higher, and it gives me a warm fuzzy knowing that everything is getting a good amount of oil in the engine.