Took my car to a local LR Mechanic to get a new Front Cover gasket - due to an oil leak. Decided to replace the Water Pump as well, just to be safe. 111K

After we got the car back, the Oil Pressure light would come on after the car was hot and ONLY while it was idling. When you step on the gas, the oil pressure light goes off.

- Oil Pump gears are correct
- Torque is right on the front cover
- Oil Pressure sensor has been replaced
- Oil pressure sensor has been "bled" perhaps an air bubble in the system?
- Oil Pan gasket has been replaced - pickup tube is good as well.
- Tried a heavier oil.
- Oil filter is the same one from 108K... so it is 3K miles old and new oil has been added. Try and replace filter?
- Check valves cleaned as well.

Suggestions? Oil Pump was working JUST FINE before it was dropped off at the Mechanic.

 

Oil pressure light should not be coming on at idle, so don' drive it until you find the problem, and correct it.

 

Your mechanic should have installed an oil pump repair kit since he was already there and especiallt at your mileage.

 

Did he change the oil? I remember reading 10w-30 oil will give you the low oil light at high ambient temps. Also, 10w-30 isn't acceptable for temps over 90*F.

 

I would drain the oil and check for any shavings. If you have any at all then you're most likely too late, because your bearings will be worn. If you don't have any then go on and replace your front cover. Some replace just the gears and I guess that's ok, but I would replace it as a whole incase the cover is worn any.

Refrain from running it at all. When you refill the oil go with some rotella 15w40 and a quart of Lucas. I always run a napa gold filter as well.

 

Why not remove the oil pressure switch, hook up the mechanical gauge, and know for sure what is happening? Spec is 10+ at idle, and 50+ at 2500 rpm hot. Above 90F spec is use an oil that ends in "w40" or higher.

What we know at this point, if switch is working as designed, is that you have less than 7 PSI when light comes on, and more than 7 PSI when engine is revved up. So you might have 15, 20, 23, etc. You really need to be sure.

The front cover gasket, crank seal, water pump gasket, and new oil pump is like $114 from Atlantic British.

Certainly try to replace filter. Was pickup tube gasket renewed?

Also, define "hot". Anything above 50% is hot in a D2. The gauge points at 50% from about 130 to 240F. Without a scanner to read it you just don't know. Running hot will make oil thin out.

Since the water pump was tinkered with, be sure to check serpantine belt route.

 

As buzz mentioned, I would check the oil pick up connection at the oil pump. It needs to be unbolted to remove the front timing cover. If a new o-ring was not installed, it may not be sealed completely and its sucking air with oil.

O-Ring Oil Pickup - 4.0/4.6 Engine (Genuine Part # ERR4794) - Land Rover gaskets and seals from Atlantic British

 

Just this past week I had the same issue "after" I had the top end rebuilt. Oil pressure light came on at idle but when we added power the light went out, then back on at idle. After a lot of trial and error, we learned it was the oil pump. This may have been the cause for my lifters banging at idle. Oil pressure registered 20+ at idle and 50 with power. New oil pump fixed it all.

 

hmmm... since oil switch turns light on at 7 PSI, how did it come on with 20+ ?

 

Maybe it was 20 psi when it was cold?