Hey guys, I've had a 2000 Land Rover Discovery series 2 for quite some time now. Couple months ago I have done a motor swap with the same type of motor and everything runs just fine except an oil leak in the back of the motor. I've heard about this oil leak before and before dropping the new used motor in the car, I took off the flywheel and replace the rear main seal. I also replaced the valve cover gaskets as well as the oil pan gasket. I even replaced the water pump. After all this was done, as well as clearing and fixing the engine codes, I've noticed an oil leak in the back of the motor that would come directly between where the transmission meets the back of the engine. This is what I know: The rear main seal has been replaced. Oil does not leak when I drive short distances. Oil does not leak when the engine isn't at mid-temperature. Oil does leak when it has been at mid-temperature for quite some time, especially after I get done driving on the highway. The temperature gauge is always at mid temp. I only get about 10 to 15 solid drops of oil every time I shut the engine off after it has been running for quite some time at mid temperature. I use SAE 5W30 full synthetic motor oil. I know that there are other areas of the back of the motor that can leak but not quite sure where, or what causes them after there is pressure buildup of oil being released when the engine is shut off. I really don't want to take the transmission off to fix this until I absolutely have to. Just curious of some more experienced individuals that have possibly any answers to this question. Thanks.

 

Check your valve cover breather on the passenger side, they get clogged really easily then you get oil leaks as your crankcase gets over pressured and oil will leak a the weakest point. Could be the crucifix seal back there leaking.

 

Check for the PCV mod. And isn’t 5w30 a bit thin? I had the same issue 2 years ago, it stopped after the pcv modification and 10w50 oil.

 

any 30 weight oil is too thin for these old engines, unless you are in artic conditions all the time.

I run 5w40 and 15w40 depending on the seasons. I have read of some in the UK who use 10w50 and 20w50.

 

@jastutte Yea in rover V8's no matter from what vehicle the brits like 20/50