I'm new to both Disco ownership and message boards. I bought a 2004 SE with 85,200 miles on it from a used car dealer in New Jersey.
This is actually my second. The first was a 2000 I got on Ebay and was never titled due to the frame being rusted out.
This time, I took it directly to a Land Rover dealer and had them look at it.
There inspection indicated three leaks - Rear Main, Differential Case and Rear Differential Pinion Seal.
During the time between ordering the parts and scheduling an appointment, the Oil Pressure Light came on briefly (basically flashed) on two separate occasions but has been off since.
I told the shop about this and they said they would look into it. After two days, I received a call saying I should either sell or trade it in because it will be too much to repair, combined with the leaks.
I'm sorry to say, but I do not trust their comments. I have had some conspicuous dealings with them before with a Jag.
Long story short, what kind of pressure should I be looking for and what are the other possibilities that would cause the light to just flash briefly?

 

Try replacing the oil sending unit... They used to go nuts on the older RRC and D1's. I haven't had a D2 do that to me yet, but I've had plenty of other vehicles with flickering oil lights or oil messages due to a bad oil sending unit/sensor. If that doesn't work it could be a clogged pickup tube or like my 97 RR a bad pickup tube oring.

My 97 RR Vitesse I bought the LR dealership had quoted the previous owner a new 9K short block due to a gummed up engine (had the LR Work Ticket to read). She was selling it extremely cheap and as she was just widowed she was going to buy a Volvo XC90 for her three little ones (all under 4 years old). Well I bought it, changed the oil and sure enough the light came on, and I did hear some clacking so I instantly shut it down....... I inspected stuff and found the oil sending unit dripping some oil out where the electrical connection was so I replaced it. However the oil light came on steady again. I decided what the heck so I dropped the oil pan and upon inspecting it I found a small nut just laying down in the pan. I was horrified at first, but then I instantly saw where it was supposed to go. The oil pickup tube support bracket!!!!!!!!!! Since it had fallen off the pickup tube was jiggling around goind down the road, and it caused the pickup tube oring to leak. I ordered a replacement, cleaned out the pickup tube, and pan. Re-installed it all, put more oil in it, and started it up. Oil Light never once came back on and I ran another 90K on that RR before selling it (due to a g/f). LR was just full of themselves and never really diagnosed a thing. Engine was not gummed up, and I got a superb LR!!!!

 

Damn good find on that pickup tube!!

 

What kind of pressure should I expect to see when at idle and 2000 RPM?
What change should I expect between a hot and cold reading?

 

I wouldn't worry about the leaks, just top them off and check them periodically.

Here's a link:

land rover service factory manual RAVE download land rover resource, service manual, workshop factory manual, download, rave, vehicles including discovery, series, defender, range rover, freelander, LR3, Handbooks, Catalog, Catalogue, Land Rover Inte

Download the Disco II service manual, often referred to as the RAVE. It will have a section that explains how the oil circulation system works and what pressures you should be seeing.

The low oil pressure is very likely due to a cracked oil pump. They are not fun, but not a gigantic pain in the *** to replace. That said, the first thing I would do is make sure you're running the right oil: 5w-40 or 15w-40 diesel oil. 10w-30 is too thin for the ambient summer temps in the US and will result in low oil pressure and increased engine wear. Diesel oil has stronger detergents and more ZDDP which is good for these engines. If you live somewhere very hot, like Texas or Arizona, I might even consider a 20w-50 oil with a ZDDP additive.

 

Land Rovers do not leak; they mark their territory. Mine is very possessive of its' turf.

 

A LR or Jeep (anything with the 4.0L) leak to let you know it's got fluid in it lol.

 

Thanks for all the ideas.
When I went and brought the 'lil one (as my wife calls it) home, I talked to the mechanic about the issue and he said it was probably a crankshaft bearing shifting which was common on these vehicles.
I haven't seen anything mentioned about this "common" problem - Crankshaft bearing movement - is it really that common an issue?
If a bearing slip is causing the problem, wouldn't the oil pressure light come on more often than twice in six weeks?
I do not know what oil was put in it prior to purchase. Would it be worthwhile to flush the system and install new oil?

 

I don't know that a flush is necessary, but an oil change would be a great idea.
With a "flush" there is always the possibility that some crud is dislodged and subsequently blocks the oil pick-up screen (trust me: I was only a 23 year old kid then, but it happened to me.)
A big oil filter will help oil pressure issues a bit. Search here for a Wix part number on the real big one. I use a Baldwin B-2.

 

OK, so step 1 is get the oil changed with a high detergent 5W-40W oil.
Not a problem, I get an appointment made today.
Without dropping the oil pan, what would be the next step? I don't want to plumb in an oil pressure gauge but how else will I know if it was the oil?
I am a firm believer in being able to see actual readings and not depend upon idiot lights to tell me when it is too late.