I have a 90 gmc 454. Just recently i had the throttle body gaskets replaced and the intake gasket replaced. since doing this my oil pressure reads different than it has before. before gasket replacement pressure was at 40 at driving speed and never below 30 at idle. it now reads 30 while driving and 20 at idle. is this normal? I had a new pressure sensor installed before gasket work and am just wondering if the leaking gaskets would show a higher oil pressure.

 

The leaking gaskets would show LOWER pressure.....this is kind of backwards of how it should have been.......are your readings in your post from before you replaced the sensor?.......if so it could be the wrong sensor...I know in the late 80s and early 90s the sensors were gauge specific i.e. 80psi gauge took one sensor and the 60 psi gauge took another.

 

befroe new sensor pressure was closer to sixty under load around 30 at idle. new sensor went to 40 under load and 30 at idle. new gaskets went from 30 under load and 20 at idle. im going to try another sensor and see what it shows.

 

Any changes to oil brand or weight? Are you due for a change? Old or different oil can cause a different reading.

 

truck back in shop, oil pressure tested with manual gauge showed 15lbs. not good. it under goes rebuild of lower half next week.hope this takes care of problem,and engine last more than 8k that it has so far.
thanks for all the help and advice.

 

Man sorry to hear that!

 

thanks ,i hear its a common problem on the 454's to blow intake gaskets and this is the price you pay. if it happens again i am pulling 454 and going to 350. maybe should have done that already.all i want is a good running truck not looking for a power house or street rod.was a new rebuild with only 8k and since im rich cant keep rebuilding motors that often.

 

Not rich