[Richard and Rhonda]

The liner slips out from the top. It has O rings to seal it in the block. It is made to be replaced.

It is a metal fatigue issue, I suppose. Internet research shows that it does happen, just like blown head gaskets, and cracked heads.

I still have this nagging suspicion that I caused this. Why? Because the problem developed the first trip after I changed the coolant. I was always suspicious that the head would need to be burped, but all the info on the 60's said no. I do know that when I refilled it did need considerable topping off. I can imagine a scenario of no coolant at that liner when I first started the engine after the change over, it getting hot, and then thermally shocked when the coolant did reach it. That would cause a crack. Is this what happened? Who knows. On the other hand, I may have been loosing small amounts of coolant since I owned the coach. All of the real root causes of the problem are merely speculation with the data I have.

But, if I were changing coolant again, I would definitely burp the head by loosening one of the two coolant temp sensors at the driver side of the head toward the front. They are a PITA to get to from the engine compartment, but easy from the engine access panel inside the coach.

I will only replace the one that is cracked at this point. There are arguments both ways. Replace them all while you have it apart, and the opposite view, if it ain't broke don't fix it.

I'll post some pics of the liner when I get it out.