I bought a 2000 Disco 2 and everything was fine untill it started knocking. at first i thought it needed oil so i would put oil and then the noise would stop. i had that prob. for about a month untill my brother blew the head gaskets. we replaced the gaskets and put new heads. put everything back together and guess what? the noise is still there. i rand it with out the valve covers and there is no oil pumping. checked the lifters and they were dry. pump is pumping, checked the pick up i just dont know what else it could be..........=(

 

Edit for misread.

 

how would loose exhaust manifold bolts cause it to have no oil flow to the lifters?

sounds to me like you have plugged oil galleys, put a can of seafoam in, run it, change oil, repeat until noise stops

 

well i
know for a fact its not a loose bolt, as far as the sea foam i tried it and it didnt work i really dont want to run it to much i dont want to mess anything up.

 

You need to do a oil pressure test.
Just because you cleaned the oil pickup screen does not mean the oil pump is working.