Oil Pressure.

[RobTJ]

My brother just picked up a 2000 TJ this past weekend.  A few hours after driving it around on after picking it up,  the Oil Pressure dropped to 0.  So it took it back to the dealer that sold it,  they  looked at it and said the sending unit was bad and replaced it yesterday. 

He called me this morning and said that it's now reading around 20 when he's on the gas and around 10 when he's stopped. 
I know mine is above 40 when I'm on the gas. 

Could it be:
Another bad sending unit.
Bad gauge.
Wrong Oil
Leak...

 

[kakirubi]

That's not right.  I would have them change the sending unit again.  What was the pressure reading when you test drove it for the first time?  My 95 XJ with 189k still reads when hot 25 at idlle and 45 or so going down the road!

 

[RobTJ]

When we test drove it,  it seem normal.  Around 40-45.

 

[RobTJ]

He took it back to the dealer,  don't know what the situation is now.

It's a 4.0
it had about 58K on it.
It didn't show any leaks when we looked it over either.  and when I drove it,  the gauge read correct (or atleast showed the same as mine).

 

[RobTJ]

Update,  after hooking up a mechanical gauge to it,  they beleave it to be the pump. 

So that is getting replaced tomorrow.   

We will see.

 

[beaker]

I had a similar problem in my old jeep.  IT was fine when it was cold but after about 20min of driving the oil pressure would drop down to 10 at idle.  Tried a new pump...still did it.  If they can't fix it, give the truck back and get the money back.  13psi is min for a 4.0.  The bearings are worn if the oil pressure is that low.

 

[RobTJ]

This dealer had put the offer of replacing the motor on the table,  if the new pump does not work. 

I told him that I wouldn't go that route and just walk away from the vehicle.