I’m new to Land Rovers but old to British and Italian cars.

My 98 Discovery 121 k miles is safely waiting at the local shop with low oil pressure.
Cold idle 12 psi and 2000 rpm 10 psi
Warm idle 8 psi and 2000 rpm 8 psi
The oil pump was replaced about 3000 miles ago by a knowledgeable Land Rover shop.

After I passed a car on the highway, the oil light flickered and then came on solid. I pulled over, turned off the engine, checked the oil = ok, and restarted the engine. No light, no bad engine sounds. It is now at the shop.

I bought this Disco about 3 months ago in Vancouver BC.
The LR was originally from California .
It came with great records of the work done by a knowledgeable shop.
Good tracking of recent oil changes, oil flush, oil light problem and a new oil pump etc.

I reviewed the current low oil pressure problem with that shop and have a good feeling that they did the work correctly. There are no bad motor sounds now and it seems that the oil is getting to all the right places, but with low pressure reading.

I live in a very remote area (2 hours to the nearest Starbucks) about a day’s journey from Vancouver. Plus my house and LR shop is under construction. This means I have to go with the local shop which has an excellent reputation but no experience with Land Rovers. I need help from my friends and not a new motor.

The oil pump was replaced, that should not be the problem
The oil pick up screen may be clogged – clean it.
The oil pressure relief valve my be stuck open – clean it or replace it.
The bearings may be worn – check them.

Based on these, I have instructed the shop this week to pull the oil pan, clean that sump area and check the bearings (thanks to this forum, I got this far).

There is another theory that oil passages may be clogged from the upper engine returning down to the oil pressure gauge. I’m not sure I fully understand this one or how to deal with this.

To confirm our success I hope to achieve with this proposed work 15 psi (lowest 10 psi) at idle and 30+ psi (lowest 30 psi) at 2000 rpm. Would these be the correct goals to achieve?

Since I’m new to this Land Rover engine, any help in solving this problem would be appreciated.

 

Here is what I think your problem is, the return oil passages are clogged and when the engine has been running for a long time the oil cannot return to the oil sump fast enough to keep adequate oil in the crankcase.

So what you need to do is a major engine flush and then remove the oil pan and clean out all the sludge that gets knocked loose.

Let the shop do it, they probably have a special machine to do this with special super duper sludge dis-solvers that would eat your face off, you know, like in that movie "Face Off".

This is a common problems with these engines if the oil has not been changed when it should or the owner used the wrong grade of gas.

After the engine flush change the oil again in 500 miles, then again at 1,000 miles then go to your normal oil change interval.

 

Thank you
That approach matches what the engine is trying to tell us.
Jim

 

Let us know how it works out.

 

Update of work accomplished so far my 1998 DI with 120k miles.
The oil pressure has improved but not there yet.

Present oil pressure (old oil pressure) is as follows:
Cold idle 24psi (12psi) and 2000 rpm 24psi (10psi)
Warm idle 8psi (8psi) and 2000 rpm 12psi (8psi)

I’m using Rotella 15w40 now for the last pressure test.
The first pressure test had Formula Shell 10w 30 from when I bought the car.

Here is what we did.
Strong detergent flush (this is the 3rd flush in 3000 miles, one by my shop).
Cut open the oil filter and observed lots of crud in the filter.
Dropped the pan – lots of scum – cleaned it.
Cleaned the oil pick up screen - ok
Checked the oil pressure relief valve – ok.
Cleaned the oil cooler – ok
Bearings worn on mains and rods – replace with new bearings.
Put it all back together.

The car looks great, sounds great, runs great, must be great.
However we still have the low oil pressure when warm.

My present plan is to drive it for 500 miles very gently.
Install an oil pressure gauge.
Change the oil and filter at 500 miles, and cut open the filter to look for crud.
I will pull off the front cover and check on the new oil pump (it was replaced 3000 miles ago).

At this point, I’m not sure what I can do to improve the oil pressure to acceptable levels.
The bottom end looks great, but where can the problem be?

 

Whee are you checking pressure? in the sensor port?

I was going to say you may want to flush the oil cooler, and Spike's theory was off because you had low numbers at startup. Now that you have high at startup, and low when it warms up, I am leaning to return passages like he said.

New bearings should have raised all of the numbers, not just cold. Have you downloaded the Rave manual? free in my sig, and it has the routing diagram for oil flow. That way you can follow it and look where you need to...

 

Your history is almost identical to mine, but I was not convinced my old pump was that bad upon inspection (new timing chain)

I'm running 15-40 rotella, my pressure is (cold 45+lbs at 2krpm, hot 30-35)(cold idle 30, hot idle 20)

Bear in mind,often two different guages will give two different readings, do not rely on just one guage.

My new $100 oil pressure guage was low by 5psi compared to my testing guage, confirmed by a third cheap guage.

Your shop's guage could easily be off by several psi and the oil light in your truck is designed to come on at 8psi, anything above that would then be acceptable @ idle.

The single biggest increase in oil pressure (10lbs. everywhere) I got was when I pulled the rocker shafts to clean the top end, I found the previous owner had installed the pass side shaft upside down.


Did your shop do the same? - If they had the valve covers off, they would have noticed the rockers were possibly filthy, and the oil return holes were plugged.

Try shutting off the engine, then immediately checking your oil, if it's in the safe range, oil returns are probably not the issue.

Keep us updated, please

luck,greg

 

Thank you okdiscoguy
My shop installed the test gauge and I assumed it was at the oil pressure switch as per the CD Rave manual that I gave them. Good question, are there other ports that you can install a gauge? This would be helpful for tracking down pressure changes. I’m a retired logical sequential engineer that loves to be a part of the machine. I try to be the doctor that asks were does it hurt, and find the problem. Test gauges are good, keep it simple, and keep the oil circulation moving. Communication between man and machine is good.
Install the gauge now!

Thank you greg409
You have been encouraging that a solution is possible.
Just keep working at it.
Good point about accuracy of oil pressure gauges, I will double check with other gauges.
I bought this Discovery in January with good records.
By the records; I see that the previous owner’s shop had the valve covers off.
It was noted that the “oil drainings to the sump were checked”.
I’m a must see for my self, so I need to investigate this further.

I’m building a LR shop now, and getting ready for some winter projects.
In the mean time, a local shop is doing the work for me.

 

Was the entire front cover replaced when they did the oil pump, or just the gears?

Your cold numbers are acceptable, but should go up as RPM's go up. The hot numbers have me stumped.. I would suggest that you install a separate gauge you can monitor yourself regardless, There is a write up for one under the filter, pretty easy to plumb.

With the low hot numbers, I would pull the dipstick cold running, and pull it hot running. That will tell you if the sump is starved when hot, if the level is drastically lower.

With all that has been replaced and the three flushes, you should have factory numbers.

 

Thank you okdiscoguy

The records show a new timing chain, gear set (oil pump), water pump, gaskets etc.
I don’t see a new timing cover listed on the invoices.
I’m reading a previous mechanics handwritten invoice with oil smudges, it is like reading history.
By observation the cover is clean from the work that was done in this area.

Your comments are encouraging, that I should have factory numbers for oil pressure.
I just need to find the problem and fix it.

I’ve noted a small coolant leak near the water pump and I want to take the front cover etc off to recheck the whole area anyway