Thread: V8 Disco1 oil leak

I can't be sure, but it could be the oil pressure relief valve on the oil pump body.

You're right.
I just looked in RAVE and it says it is the Oil Pressure Relief Valve.

So the big question is
Is the valve relieving high pressure or is the O ring buggered?

Guess I'll find out on the weekend.

Originally Posted by Utemad

You're right.
I just looked in RAVE and it says it is the Oil Pressure Relief Valve.

So the big question is
Is the valve relieving high pressure or is the O ring buggered?

Guess I'll find out on the weekend.

remember to Wear safety glass to protect the eyes just in case.
Pls post what the cost was for parts and repair times.

I'll be doing it this weekend most likely.
It's been leaking for around 12 months or more though. Only just bought a pressure cleaner so I could get rid of the crud and find the leak though so things don't happen too fast around here

I envisage all I will need to do is replace the O ring.
Cost should be under a dollar and time taken will be short.

Once that is done I will know if there is something bad happening or not. Given how long it has been weeping my bet is it is just the O ring or some failure of the other relief valve components.

I am assuming that excess pressure is meant to be bled back into the sump as opposed to the outside of the pump. I've never had one apart before as you might be able to tell...

Just thought I'd post this up here to answer my own question about how the over pressure valve works.

The fourth characteristic is the overpressure valve. This can usually be found by looking down inside the threaded outlet hole and seeing if there is a coil spring, usually about an inch diameter and an inch long, near the bottom. This spring holds a steel disk over an aperture, and if the pressure differential across the filter element exceeds a preset amount (usually 8 to 12psi), such as may occur when starting an engine long overdue for an oil change on a very cold winter's day, the valve disk lifts up against the spring and allows (dirty, unfiltered!) oil into the outlet, thereby saving the oil pump and the engine from immediate (not long-term!) damage. Later filters have a phenolic plastic overpressure valve, viewed by looking into the threaded hole to the bottom, and noting the approximately one inch diameter head of the valve. However, in the Rover V8 application, this feature of the filter is less important, since on many of the engine derivatives, there is already such a valve built into the pump. The small thimble-shaped screen covering the pressure relief valve is usually directly visible. (In applications which have the oil cooler adapter is fitted, this will have to be removed to see the overpressure valve.)

Land Rover FAQ - Repair & Maintenance - Range Rover

I took it apart tonight.

The O ring is completely shagged. I would assume it was meant to be rubber looking and pliable like all good O rings.

This one is all hard and snapped like plastic when I tried to remove it
Well passed due for replacement it appears.

Oil must either seep past the piston or come back down the bypass route. Otherwise there would be no oil to leak out of the dead O ring. I guess this is normal though as otherwise there would be no need for the O ring. Would be the same oil that ran out when I removed the plug.

Here's a handy hint, If you lose the circlip look on top of the steering box

Originally Posted by It'sNotWorthComplaining!

remember to Wear safety glass to protect the eyes just in case.
Pls post what the cost was for parts and repair times.

Job's done.

Did it on Saturday and the oil that used to drip off the oil filter and coat the driver's side of the block has not reappeared.

Total cost was 30 cents for a BS017 O ring.
That is 11/16in ID x 1/16in according to Google.

Only special tool required (if you could call it that) was a pair of 90 degree internal circlip pliers.

Took 5 minutes to get it all apart and about 4 hours to get it back together. Had to remove the aircon compressor and one of the oil cooler lines to get access to press the cap back in with my thumb. Luckily the new O ring would hold the cap in place long enough to refit the circlip before the spring pushed it out again.
Pushing the cap in took many goes though. Very limited access and pushing it in straight was quite difficult.

Hope you got Viton or that o'ring will be hard again in 6 months...