Thread: 3.9 v8 oil pressure

Cheers, will give it a go over the weekend.

Hi again. Pulled off the oil pump to find a bit of scoring. Assume this to be my low oil pressure problem. Question....can the bottom assembly be machined flat? The gouge in the upper housing, is it too far gone?

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I have 2003 D2 V8 4.0 (130 000km), I was sand driving and oil light came on whilst idling, I continued driving to safer grounds and then came loud ticking noise. I replaced oil and filter,engine stopped ticking and light went off, so I drove home.
The next day I started engine but the light came on at idle again.I decided to pull down engine,removing timing cover to find a CRACKED outer oil pump gear..
I replaced with new the timing cover (includes oil gears,relief valve,pressure sender and seals) New timing gears and chain as they where badly worn,exhaust manifold and flange gaskets all with new genuine parts ,I also replaced oil pickup o'ring, sump gasket and installed a oil pressure gauge, all done by the rover overhaul manual specs and thoroughly cleaned all parts before reassembling.
After all that work, and adding a thicker oil (15-50w instead of recommended thin 5-40w) I started engine to find it was running much smoother and quieter BUT still has zero oil pressure at idle after engine warms up ???? The pressure rises when engine is revved but then rapidly falls back to zero when revs drop??
So I have pulled the engine down again to find more issues!! the upper conrod bearing shells are partially worn down to copper?? I have replaced conrod shells but My guess is that the big end bearings also needs to be replaced whilst the engine is pulled down? but I dont think it is possible to correctly replace the big end bearings without removing the engine as it looks near impossible to achieve the correct torque settings that could result in catastrophic engine failure...
Why is my bottom end in such bad shape? this is a low km well maintained Disco that has had an easy going street life (soccer mum suv) and has never been off road until recently?
Im guessing the top end is also in need of a rebuild?
This low oil pressure problem has already cost me $2000 not including tool costs and thats doing the work myself, I would hate to know what a rover mechanic would have charged me..

Originally Posted by James445F

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...So I have pulled the engine down again to find more issues!! the upper conrod bearing shells are partially worn down to copper?? I have replaced conrod shells but My guess is that the big end bearings also needs to be replaced whilst the engine is pulled down? but I dont think it is possible to correctly replace the big end bearings without removing the engine ...

The bearings on the bottom of the connecting rod are the big-end bearings.

I think the ones you are calling "big-end" are actually the main bearings, which support the crankshaft.

I replaced mine some time ago, whilst chasing a noise inside the engine, but I came to the conclusion that removing the crankshaft was the easiest way to do the job, which means taking the engine out.

Good on you for having a go at doing it yourself and you would have saved thousands of dollars by the end of it all,

Cheers Charlie