I had a client of AffordableEngine.com buy a rebuilt 03 Discovery engine from me and I got quite a bit of information from the rebuilder that I wanted to share.

It seems that prior to 2003 the Discovery had a problem with the timing cover fitting properly. This fit failure would cause the oil to not circulate properly and the oil pressure to be low. This would lead to overheating and ultimately the cylinder sleeves failing. If you have a chance, you want to switch your covers to the newly designed version to head off this problem. Also, he said it was very important to use the factory oil filter with the check valve, 20/40 weight oil and premium fuel. Avoid spending $6,200 like my client had to...

 

Oil pump issues in the 2003 model are well known. Does your rebuilder have a reasonably priced replacement front cover?

 

20w-40 is not available here in the US, but 20w-50 is.

 

Not sure. I think he may of said you can get it from the LR parts department.