Re: 1992-93 RR classic 3.9 Over heat when up hills or traffic
I had this problem with my 91 RRC. It turned out to be the two rear cylinder sleeves had separated from the block. There were no coolant leaks, oil leaks or any other signs. Just the over heating when going up hill or sitting in traffic. I ended up having to replace the block. When I did I opted to upgrade to the 4.6 block and nearly everything from the 3.9 fit on it.