Is it normal for an older 4.3 engine with over 200k miles on it to have oil pressure that starts off cold at 60 and when warm, drive at 40 and drop to 30 at idle?

puralator filter and 5w 30 castrol oil.. Thanks in advance of any replies...

 

thats what mine does and its a 2002, No noises or anything wrong yet..I just kept having problems with water pumps but got that settled finally..

 

Yep, you're safe. The old 'rule of thumb' is 10psi for every 1,000RPM. I believe Chevy says the minimum idle pressure is ~10psi.

 

Not to threadjack, but mine is similar, except that it starts off about 60 and slowly decreases until when the engine is completely warmed up the pressure is so low that the check gauges light comes on and the oil pressure is reading about 10. I was thinking the pump just needed to be changed, which is kinda pain, but is that not necessarily the case?

 

Be careful...if at idle (1k rpms and below) you canget away with 10psi. If the rpms are anything above 1,000, you're not getting enough oil pressure. While the problem could be the pump, it may also be that the oil is getting too hot. What temperature is your engine running at? What type of oil are you using (ie. 5w 30?)

 

Ya, it's only at idle. As soon as I get on the gas it jumps up to about 40. The temps are totally normal, and I'm running 5W-30. I read somewhere it could indicate worn bearings [:@]. Any truth to that, do you think?

 

You're playing in the red zone. Put a manual gauge on the oil pressure sending unit connection and see exactly what the pressure is. You need to find out if it's the sender or the oil pump itself going south. Remember, the oil pump does not create pressure, it creates flow. The various restrictions in the oil path are what create the pressure.

 

Yup, the pumps only create flow, I love seeing those 'high pressure' pumps!! LOL. Well anyway, I agree with Riddle, put a manual gauge on the motor, and see what the motor really has for pressure. It could be just as simple as a bad sending unit. Good luck.

 

Will do. Thanks.