Howdy,

Normally the oil pressure in my 2001 Blazer 4.3 4x4 idles at around 55-60. Today I was towing my trailer roughly 60 miles, and after dropping it back off, my oil pressure is now idling just under 40. The oil level hasn't changed, and nothing is leaking or making any new noises.

Is this normal?

PS: This is the trailer. I know it's a bit big to be towing, but it handled just fine.

 

40psi is normal @ idle with engine at full temperature.

 

I only get around 20 at idle and around 40 while driving when it is warmed up. Around 40 at idle and 60 while driving when it is cold.

 

I'm always reading 65 psi cold at above 2000RPM, always reading 45psi at 70mph (2000 RPM) when thoroughly hot, and always reading 25psi at idle with A/C on in drive (580 RPM) when thoroughly hot. Oil pressure at idle when hot seems to be highly dependent on exact engine RPM and can vary significantly with a very small change in RPM. Mine has is 3100 miles on new GM crate motor. 5W30 non-synthetic oil.

Looks like mine is 5psi higher than yours across the board. Probably just a difference in calibration of oil pressure sending unit, but mine also could be a little tighter clearances because it is new - haven't put my mechanical test gauge on it as my oil pressure is no longer a concern.

To the OP - 40psi at idle when hot is definitely not likely to be happening when using the correct 5W30 oil and a normal (non hi-volume) oil pump. Possibly a gauge problem. Put a mechanical test gauge on it.

 

Mine has around 125K on it, so I would guess that is the difference.