I am replacing the cylinder head on my camry 87k miles on it. I was wondering if it would be a good idea to replace the cylinder head bolt set too. The car just started losing antifreeze around a couple head bolts but it isn't overheated. But after loosening the bolts, I noticed that the head bolts at the back of the engine are quite loose. What the cause of this?

 

What is wrong with the old head?

After the head is removed inspect it for warpage.

A new set of bolts is inexpensive and cheap insurance.

Clean the bolt hole threads in the block with a tap and oil the bolt threads with motor oil.

 

You may wish to check this thread on Toyota Nation. It looks like some of the bolts/blocks were defective. There is a fix for it, but it costs around $1,500 to have the block rethreaded and the bolts replaced.