xander

ive just installed a new motor in my 2001 jeep cherokee. im still getting low oil pressure reading from my guage... ive switched out the pressure switch to a new one and im still getting a low reading on my guage... and when it get hot from lots of driving it has dropped to zero psi reading on the guage but do not hear any ticking noise from motor. do i have a bad guage in the cluster or what... HELP

bigbadon

Exactly what do you mean "new motor"?

s346k

have u checked any of this against a mechanical gauge?

xander

Ordered remanufactured motor from Spartan at advance auto. And no I have not checked pressure with mechanical guage.

bigbadon

1st things first....verify with gage.
Re-manufactured engine builders target bearing clearances on the high side (loose engine) that can cause a lower than normal pressure but it should not be that low.
If you verify that it actually has low pressure I would immediately contact Spartan/Advance.
What type and weight oil and filter are you using?
What is your pressure at 2000 rpm?
What is your engine temperature?

xjsnake

Also, include the basics. Year and engine size please.

And ABSOLUTELY verify the pressure reading with a mechanical gauge.

bigbadon

Good point. 4psi at idle is normal for the 4.7 V8. I assumed this was a 4.0

jebmccall

4psi being normal is weird....... anyways stock specs for the 4.0 is minimal 13psi at hot idle and 37 plus above 1600 rpms. now iwth it being a new reman engine i would expect to see 40-50 at idle and about the same throughout the rpms.

tjwalker

Verify, verify.......

If you don't have a mechanical oil pressure gauge, they can often be rented inexpensively from your local parts store; call around.

Report your findings.

zkdawg

how and where do u hook up the mechanical gauge?

playbass

The mechanical gauge will connect to the same port as the oil pressure sending unit.