i have had an oil leak on my car so i jet washed the engine to see where it was coming from and the car now will not rev abov 4k and just keeps banging and popping, also the oil seem to be coming between the block and head but no fluids are mixing.

the car starts and drives fine upto 4k so maybe it has water somewhere but the oil leak concerns me more
it has a WRC head gasket and was wondering if it needs re tourqin or if they can be re torqued but can't understand why theres no fluids mixing oil/water.
there is a possibility the oil is coming from somewhere else and running down but i can't find it.

any help would be apriciated.

Pete