I had a similar oil light issue and ended up changing the oil pump and it went away although it didn't really raise my oil pressure that much but enough. I also did not have a broken oil pump, just old and worn I guess. The thing is these engines when perfectly normal can have very low oil pressure at hot idle it seems. So if you get the light blinking it is dropping to about 6-7 psi. Normal is considered anything above that. Mine, which is tired at 180k will drop to about 10psi at hot idle after a highway run. It will blink at 10 psi on my Glowshift pressure gauge but not the dash. It stops once the truck is off load again and driven slower. I contribute that to valve train wear, bearing wear and just engine wear. But it's considered normal. A general rule is that oil pressure should be about 10 psi per 1000 rpm or so. With our trucks I think it's more like 15-18 psi ideally which gets about 35 - 45 psi at 2500 rpm and should hold 15-18 psi at idle. Mine will hold 42 psi at 2300-2500 rpm on the highway and anywhere between 10 - 25 psi at idle depending on how hot the oil is.
In your case I am going to guess that if your engine is stalling, it's dropping below the 750-780 rpm idle and when it does, before cutting off, the oil pressure is reading really low. Like 500 rpm idle = 5 psi = oil light. Why it is dying is another issue.

 

Gonna try to do this.

 

Thanks for the information. Engine was not actually stalling yesterday. It had stalled a few months ago while using 5W-30 oil. After switching to 10W-40 it never happened again. Went out this morning and noticed oil level is low. Going to put a quart of 15W-40 in and pray that this will hold the oil pump over until I can get into a mechanic next week.

 

Checked the oil dipstick was almost at the "add oil line". Put in about half a quart of Rotella T4 15W40, almost at the top now. Not gonna start the start/drive the truck until I take it into my mechanic in the next few days.

Cleared the P1668 code on my UG as well.

Thanks everyone.

 

P1668 is the following:
Engine anti theft circuit signal high Serial link Open Circuit

Don't see that having anything to do with oil pressure.

 

It's cleared now, regardless.

 

Yes, the real question here is...is the oil light coming on because it is running so poorly at idle...or...it has low oil pressure at idle because of defective pump or worn engine components. Low oil pressure will not stall engine, unless completely gone and it seizes up. There is no fail-safe that shuts down engine with low oil pressure on these Dll's. But, an engine that is running below recommended idle or so rough that it's barely running or about to stall or actually in the act of stalling...will set low oil pressure light.

I believe, by the sounds of it anyway, that your real issue is a poor running engine. You need too get the engine diagnosed and see why it idles so poorly.

 

Trying to get exact numbers from the compression test my mechanic ran, they told me that "it was all over the place". Quoted me for a new oil pump at like 20 hours worth of labor and then said "it's not worth it, it's cheaper to just put a new engine in when the time comes" and told me to drive the disco until the engine is completely done for. Should I take this opinion with a grain of salt? They've put changed the oil. 10W-40 and a larger filter telling me that is the best they can do for the truck right now.

Anyone have any sort advice for this? Just trying to hear some opinions from Rover enthusiasts on here.

 

20 hours for an oil pump that sounds high to me. But ask exactly what the compression readings were all over the place is a bs answer they should be able to tell you exactly what each cylinder is for each test.

 

You need a different mechanic, is he a LR specialty shop? Never take a LR anywhere but a specialty shop.