So the oil light on my '04 Disco 4.6 V8 has decided to come on intermittently at idle when the engine is hot. The shop tested the pump and said all the measurements came back within normal range. They changed the switch but that didn't help. There are no other symptoms, i.e. no knocking, rough idling, overheating, or anything like that. Should i just prepare to replace the oil pump or is there a chance it could be...something else?

I'm running SAE 5W-30 with 107k miles on it.

Thanks!

 

Im in the same position you are. I’m in the process of finding a fitting to hook up my pressure gauge to it
I replaced the pressure switch yesterday drove it today and after 30 min light came on again


I’m thinking either the pump is starting to go when hot or I got a bad oil filter

what oil filter are you using

 

I’d say cam bearing issue, if it does it after it’s warmed up. #3 cam bearing has walked on a few 4.6L’s I’ve messed with.

 

How hard or what is the fix of in fact it is this

 

You have to pull the engine & disassemble it to gain access to the cam bearings. Front timing cover has to come off, valve covers, rocker assemblies, lifters, rods, and then you can remove the cam to gain access to the bearing races.

You can remove the oil pan & inspect them from the bottom. Check your Oil Pressure with a gauge first though!

 

You might try running a thicker oil to see if that is a temporary help. Most people are using 15w40 or 20w50 fossil oil.

 

I use 10-30 and never had this issue this happen right after I changed my oil

I’m going to replace oil filter and change oil again as somehow this is to close ti when I changed the oil

 

I'm at 470 000km and use 20w50 now in the summer. I installed an oil filter sandwich plate and hooked up a pressure gauge many years ago. At operating temperature my pressure swings from 40psi at idle to 60psi while driving. Get a pressure gauge hooked up.

 

Just hooked my my gauge at cold start up it’s at 50 psi
than just keeps dropping once it’s warming up went down to 10 psi.
Will change oil and filter and see what happens
if nothing happens it’s going to sit for a while

Are these also the symptoms of a failing oil pump ??

 

Switch activates below 3.5-6psi. Looks like you have short pressure drops not indicated by your oil pressure gauge.