Hey All,

So this past weekend I replaced my cracked 0331 head with one from Clearwater. Pretty impressive new Cast. Overall project took me 2 days as I used opportunity to really clean things out, check vacuum hoses, etc.

My main concern or questions is when I was done, i put new OIL and Coolant. What is the normal Break-In period for a new Cylinder head? How long should I drive it before changing oil and coolant again ? My Previous Cylinder head was kind of sludge packed so I can only assume the crank area is similar, should I run some type of Cleaner etc before I change the oil again? What are some common practices for post cylinder head replacements.

 

I would change the oil in about 2-500 mi. to be sure that all the coolant has been removed from it, then you should be good to go. But that's just me oil is cheap and easy to change to make sure all the coolant is flushed from oil.

 

^ This. I recently did the same head replacement job on my '98 XJ and changed the oil refilling with Shell Rotella T6 for the first time. There was definitely coolant in the old oil. I also changed every other fluid I could since with that new Clearwater head she'll likely go another 200k miles and there's nothing like a fresh start.

 

Ya I put in Rotella T as well and now I wish I had just bought some cheap oil knowing i would just replace it so soon lol. Oh well whats another 20 some bucks .