low oil pressue at idle

[killab443]

I recently noticed on my 6 bolt 1g that my oil pressure was on the low side at idle. I picked up a Vdo electric oil pres. gauge to confirm it wasn't my stock sending unit. The new gauge is reading around 5 psi at idle. Not good. One of my most recent mods was installing a 90 oil cooler housing. Ive driven the car for 2k miles with this housing and didnt not have any issues in that time with oil pressure- until the last 100 miles or so. I was under the impression that this may add pressure not lower it. The relief is stock sized hole on this housing, no porting. Previous owner of the motor eliminated balance shafts as well not sure on the age of the oil pump either. Also the oil pressure is fine at start up on idle. (Stays around 25-30 idle) but once the motor is up to temp its no more then 5 psi at idle and 80 psi at wot.
Any input on this being a housing issue or an oil pump issue?

 

[Cornfed4G64]

Isn't stock 8psi at operating temp idle?

 

[WES_393]

Isn't stock 8psi at operating temp idle?

Idle oil pressure should be around 12psi.

 

[miguelmcv]

What oil grade are you using and what temperature is now where you live? (whether)..

I was running 15, 18 PSI fully warm and it came down to 8, 7 and sometimes to 5, It's around 90, 95dgs right now so I changed to thicker grade of oil, and it brought it up to 10,9, and some times to 7 though.

 

[killab443]

I'm using 10w30 you think I should change?

 

[91mits]

use 20w50...definitely help you

 

[WES_393]

10w30 is generally too thin for these cars. Try 15w40 Rotella.

 

[Diamond Star Werks]

I wouldn't say the oil they came with is too thin. I've used 0w20 before and didn't have an issue but I just went off my stock gauge so can't give numbers. I just run 20w50 vr1 oil now since it's cheaper than the ams oil 0w20 and good oil.

 

[JacksonAuto]

Low pressure at idle is indicative of more bearing clearance. As long as it goes up with RPM things are mechanically sound inside the engine. It is evidence that things are beginning to wear, though. I wouldn't be worried at the moment but definitely start planning a rebuild.