Exhaust leak??

 

Good call, maybe.
Check for loose exhaust manifold bolts.

 

I have the same knock that you describe here...I am not a mechanic and don't really have one as no one will work on a rover around here. Got a bunch of questions here so please be patient and sorry to hijack your thread gtagg...

What is a knock sensor?
How do i check for an exhaust leak?
What is an oil separator and what does it look like?

Thanks as always...

 

Knock sensor: there is one on each side of the engine block. As the name suggests it detects engine knock or pre ignition or detonation or pinging. Check the wire going to the knock sensor, mine was damaged by the PO when they did a head gasket job. The knock sensor is the black plastic part in the photo.

Exhaust leak: a simple test is to take a length of hose and hold one end to your ear and poke around the exhaust manifold with the other end, you will hear pretty soon if there is a leak. The engine must be running...

Oil separator: on the right rocker cover you will see a rubber hose attached to the top of the cover, remove the rubber hose and you will see a metal tube with a small hole. Remove the tube and inside is a plastic goodie, this is the oil separator. You can wiggle the oil separator out and clean it with carb cleaner or some degreaser. If it breaks you can get a new one at AB:
http://www.roverparts.com/Parts/LLJ000010.cfm