What straight wt oil to try for 2000 RHD Cherokee

[jeepman3071]

Originally Posted By: rslifkin
On a 2000, the head probably cracked when it got hot (0331 head). Has it been losing coolant? If so, the bearings in the bottom end are probably shot if it's got low oil pressure, as the coolant has likely wiped them out.

If the oil isn't milky, no slime under the oil cap and it hasn't been losing coolant, then verify the pressure with a mech gauge and replace the oil pump if it's actually low (worn out oil pumps aren't uncommon on high mileage 4.0s).


This.

 

[SwampSurvivor]

A lot of times, 4.0s will run hot enough to evaporate the coolant so you don't end up with the milk on the oil cap ... even with a cracked head.

 

[rslifkin]

Originally Posted By: Miller88
A lot of times, 4.0s will run hot enough to evaporate the coolant so you don't end up with the milk on the oil cap ... even with a cracked head.


Huh. When my mom's cracked the head, it had almost a 1/2" of slime under the valve cover and on the oil cap and valvetrain after a couple hundred miles (she noticed it losing coolant, I checked it out and found it before any lasting damage was done). It took forever to clean it all up before reassembly.

 

[Donald]

Have you changed the oil filter since the light started to come on? If not that would be the first thing to do.

I had a 1994 Camry where the oil light would come on. Mechanical gauge confirmed oil pressure issues. Changed only the filter (Amsoil) and problem went away. Amsoil evaluated the filter and said the filter was full, but not defective. So unknown problem with a top quality filter.

Put on another 100K miles and never any more issues.

 

[artificialist]

If you really need an SAE40, you can probably get it at a marina because many boats still have a Detroit Diesel 2-cycle engine which needs SAE40.

I wouldn't use STP, approved oil already has the additives that are needed.

 

[circuitsmith]

If it's not the sender it's most likely worn main crank bearings causing low pressure at idle.
How many of you saying change the oil pump have actually seen a high mileage & low pressure problem fixed with a new pump?
The pump is low, closest to the sump so it's the last part to get starved of oil.
Normally it's constantly bathed in the oil at its coolest.

 

[andyd]

The rattle on cold start up. Thats a worn thrust bearing on the crank. It prolly has a few miles left.But it is showing wear. I would switch to 20 w 50. I use it down to 10F in my cars which are specced for it.