Noticed that my oil light came on yesterday. It would only come on in reverse. As soon as I put it in drive or park it would go out. I checked the oil and it was a little low. Not quite below the add line just a bit above it. Added a quart, started and shifted it in reverse and back into drive several times. The light flickered on and off a few times and then went out and didn't come back on after a couple of minutes. Drove it to town this morning 10 miles never came on, to and from. Then went on a 30 mile trip later today. Light started to come on in reverse and then would go out as soon as I would put it in gear. Let it sit for a few hours after getting home, checked the oil level (little over full) shifted it in and out of reverse never came on. Is this the sensor going out or should I park it and replace the oil pump?

 

You could have a bad switch, a skinned place in wire grounding out when engine wiggles on motor mounts, or oil pump problems, or oil pickup partially blocked or bad seal making it suck air. Way to sleep better is to do a mechanical oil gauge PSI test, cold and hot, idle and 2500 rpm. Four numbers. Post back.

 

So, how mechanical are you? I would suggest you not drive the Disco until this is resolved or you may trash your engine.

 

That is always the safe bet, as the idiot light could be telling the truth, which is that you have less than 7 PSI of oil pressure. Of course, the reverse is true, you might have 10 pounds of pressure, and light will be off, but you are at 2500 rpm where it should be 50+.

 

Not going to drive it until I rebuild the oil pump. I have been trying to get a hold of D&D Fab. to see about some possible cam upgrades while I have it apart but have not got them to answer yet.

 

You don't have to pull the cam to do the oil pump. New cam would mean new lifters also. While oil pan off might exam main bearings, which can be changed in the truck. That oil pickup can be cleaned, and gasket for it renewed and two drops of loctite on the bolts to keep them on duty.

 

Another one, I hate it for you and it sounds all too familiar..does the light come on when the truck is at idle at the lowerst rpm's? This was the case with mine and the oil pump /gears were shot..leak down test would be my first recommendation.

 

No, it doesn't come on until the engine is warmed up and only then when you put it in reverse. I think I will do a leak down first maybe. Seems to have as much power as it did before. I drove it for 60 miles since the first time the light came on. That trip it never came on until I stopped about 10 miles from home to go to the store. It only came on while I was in reverse. As soon as I put in drive it would go out.

 

I meant while I have it pulled aside and out of service. I have been planning on replacing the head gaskets. I think that is where my coolant is going. Has to be topped off every 3-4 months.

 

A coolant leak that small, with no other signs (white smoke, overheating, gurgle sounds under dash) could easily be other things besides HG. Coolant cap could be bad, not holding pressure, so when driving you are dripping coolant out the overflow. You can do a chemical test for exhaust gas in coolant.