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eauto
eauto, The Car Guy
Category: Jeep
Satisfied Customers: 15075
Experience:  ase mechanic 16 Plus years in the field
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I have a Grand Cherokee Jeep, approx. 1990, automatic, 360,

Customer Question

I have a Grand Cherokee Jeep, approx. 1990, automatic, 360, V-8. Why am I not getting any oil pressure? No, it is not the gauge.
Submitted: 1 year ago.
Category: Jeep
Expert:  eauto replied 1 year ago.

has he checked oil pressure with a mechanical gauge?

Customer: replied 1 year ago.
I believe so
Expert:  eauto replied 1 year ago.

can u confirm?

Customer: replied 1 year ago.
He said no, he changed the oil pump housing and the gasket.
Expert:  eauto replied 1 year ago.

can he check it with a mechanical gauge? that will tell us if its a internal engine failure like rod or main bearings or a external issue like a failed gauge or a harness issue

Customer: replied 1 year ago.
he has checked it with a mechanical gauge, he just confirmed with me. There is no oil pressure.
Expert:  eauto replied 1 year ago.

then its internal either a oil pump failure or rod or main bearing failure...

Customer: replied 1 year ago.
it was leaking by the oil pump so he put in a new oil pump gasket in there took out hte 2 gears in the pump and checked those and put it all together
Customer: replied 1 year ago.
He changed all the oil, it ran fine, but no oil pressure. Can there be an oil vapor lock?
Expert:  eauto replied 1 year ago.

did he check the rod and main bearings for scoring or wear?

Expert:  eauto replied 1 year ago.

did he prime the oil pump..? and no on the vapor lock

Customer: replied 1 year ago.
That is his question to you.
Expert:  eauto replied 1 year ago.

did he prime the oil pump?

Customer: replied 1 year ago.
when he put the oil filter on, he filled it up and then screwed it on. How else can you prime the pump?
Expert:  eauto replied 1 year ago.

and this is a 1990?

Expert:  eauto replied 1 year ago.

did he check the gears with feeler gauges?

Expert:  eauto replied 1 year ago.

have him check the oil pump here is the proper procedure.......

  1. Remove drive gear and idler gear assembly from pump body.
  2. Remove oil pressure relief, retaining cap and spring assembly.
  3. Using the preferred method, measure gear end clearance as follows:
    1. Place a strip of Plastigage across full width of each oil pump gear.
    2. Install oil pump cover and gasket. Torque cover bolts to specification.
    3. Remove pump cover and measure width of compressed Plastigage.
    4. Gear end clearance should be 0.002 - 0.008 inch.
  1. Using the alternate method, measure gear end clearance as follows:
    1. Place a suitable straightedge across gears and oil pump body.
    2. Place a feeler gauge between gears and straightedge.
    3. Gear end clearance should be 0.004 - 0.008 inch.
    4. If gear end clearance is excessive measure gear length. If gear length is correct install a thinner oil pump cover gasket. If gear length is incorrect, replace gears and idler shaft.
  1. Measure gear tooth to pump body clearance as follows:
    1. Place a suitable feeler gauge between gear tooth and pump body inner wall directly opposite point of gear mesh.
    2. Rotate gears and measure each gear tooth clearance.
    3. Clearance should be 0.0005 - 0.0025 inch.
    4. If gear tooth to body clearance exceeds specified limit, use a micrometer and measure gear diameter. If gear diameter is correct and gear clearance is correct, replace cover. If gear diameter is incorrect, replace gears and idler shaft.

..

Customer: replied 1 year ago.
Do you have a simple answer as to how to prime the oil pump.
Expert:  eauto replied 1 year ago.

a little oil in the pump and fill the filter and crank