Sudden Drop In Oil Pressure

[crazymjb]

My oil pressure gauge usually reads 40 PSI at a relatively broad RPM band, and hits 60-70 under load or WOT. When we restarted the car(parked on a steep hill if that matters) the pressure gauge was reading near 0 at idle, and under WOT in park, or WOT in first gear it is only going up to 25 to 30psi. No oil pressure light is on.

 

I have a 1996 with a 350, replaced with a crate 350 at a dealership about 70-80K ago. An oil change is due soon so I am curious as to what you think I should do (possible stuck relief valve in filter) . Also, is there any way to manually check oil pressure?

 

Mike

[Koinz]

Stick a mechanical guage on it to verify pressure. If it's good, replace the oil pressure sending unit.

 

Oh, and make sure there's oil in it

[crazymjb]

Just checked again and now the pressure is reading as it was. I assume(hope) this is uncharacteristic of a failing oil pump?

 

Mike

[IMFLYN]

Just checked again and now the pressure is reading as it was. I assume(hope) this is uncharacteristic of a failing oil pump?

 

Mike

 

Edit - my bad, I missed that post. Sending unit going out would be my first inclination.

 

Are you getting any knocking sounds?

[crazymjb]

No new (only that crunch crunch crunch of the failing belt tensioner) distinguishable sounds now or when it was reading low... The incline wasn't THAT steep, I've been up steeper without a problem. I also was only sitting there for about 2 minutes with the engine actually off.

 

Mike

[crazymjb]

Where is the oil pressure sending unit located on these trucks (1996 350CID V8)

 

Mike

[Xc Special]

behind the distributor,

also , zero oil pressure , youll notice the loud, ticking , knocking going on LOL

[crazymjb]

I figure it must be the sender... when I first got it, the thing would peg at 60-80 and stick... Now its going up to 40, sticking for 10-20 minutes, no matter what, than dropping to zero and going between that and 20... No noticeable engine difference.

 

Mike

[ken1mod]

oil pumps are more reliable than sender units. never seen a bad chevy oil pump.

[deuce242]

My oil pressure gauge usually reads 40 PSI at a relatively broad RPM band, and hits 60-70 under load or WOT. When we restarted the car(parked on a steep hill if that matters) the pressure gauge was reading near 0 at idle, and under WOT in park, or WOT in first gear it is only going up to 25 to 30psi. No oil pressure light is on.

 

I have a 1996 with a 350, replaced with a crate 350 at a dealership about 70-80K ago. An oil change is due soon so I am curious as to what you think I should do (possible stuck relief valve in filter) . Also, is there any way to manually check oil pressure?

 

Mike

 

I have a similar problem. I have a 2000 suburban 6.0 and the oil pressure when I start it will be at 0. It sounds like a diesel truck. then it will go up when I give it gas. But then it will drop again. It has a new oil pump in it. I dont know what it could be. Do you have any suggestions? I could use all the help I can get.