Oil pressure...???

[magnesium]

I have a 350, 1976... When cold, oil pressure is at 40, When hot, oil pressure at idle speed is about 20... hot, cruising speeed about 30... is this normal? or too low??

 

[brusso]

Only going by the car's oil pres gauge, mine is similar. Cold idle 40, highway cruise 40, hot idle nuetral 35, hot idle drive and stopped 30. Oh, it's a stock L48 350 auto.



P.S. The cars has about 93,000 miles.

 

[magnesium]

Thanks...

 

[Jack]

mag:
I think your model ('75 and newer) has an electric op gage. Electric op gage has a "sending unit" (acts as OP sensor) screwed into engine block. OP sending units with a lotta age are notoriously inaccurate. Suggest you get a new GENUINE GM sending unit ... don't substitute other brand as they are often not calibrated to GM spec.
JACK:gap

 

[tom102]

Oil Pressure

My 76 has about 50 lbs on a cold start then drops to about 35 at warm idle and runs at about 45 or 50 at highway speed. I had to change my sending unit several months back as the original was reading way off (too low)

 

[76okievette]

My 76 is the same as Tom's I run approximatly 50 at cruising speed.

 

[Twin_Turbo]

it's normal, when the oil gets hot the viscocity goes down, meaning it's thinner. Thinner oil has less problems making it through the oil passages so the restriction is less. Pressure is a restriction to flow > pressure goes down.

 

[magnesium]

it's normal, when the oil gets hot the viscocity goes down, meaning it's thinner. Thinner oil has less problems making it through the oil passages so the restriction is less. Pressure is a restriction to flow > pressure goes down.

I ve changes the oil today for 20/50... now its steady at 40... great!!! thanks buddy