i have a 91 xj,my motor has 267k miles on it,it started to knock but only wen i just let off the gas and when it is just cranked up,it wont knock but for a sec but i can still hear it,i took my head off and i couldnt find my head gasket lol and i had milky water like stuff in my back cylinder,what should i do,i dont even know where to start really,i was just gonna put it back together and drive it till i throw a rod threw the block but i rather fix it the right way,please put me in the right direction

 

You couldn't find a head gasket upon disassembly?! Uh, OK...

Sounds like coolant and oil are having a party and you're not invited. If it's not the head or gasket, you may have a crack somewhere that's letting these fluids mix. Woulda been a good idea to do a compression test before removing the head, but...

 

check for cracks since youve got the head off....maybe try reassembly with a new gasket and check compression as previously mentioned, that might help you narrow it down...no gasket happens alot in marine motors due to high corrosion, possibly salt...im not sure ive ever seen one deteriorate in an automotive engine tho, but im sure it happens

 

Pull the oil pan, check for play in the bottom end of the motor.

 

Water in the cylinder is most likely a blown head gasket and the knock could be a rod or crank bearing that's starting to go. With 276K on the engine I'd say it's time to let it go. Any money spent keeping the engine running would probably be better spent on a new engine. I'd Head to the wrecking yard and find a fresh replacement for a couple hundred bucks.

 

Water in the back cylinder on an inline 6 means you just pulled the head off an inline 6. I've never been able to pull one without getting coolant in there. even after draining the radiator.