After having my temp do the hot/cold thing while warming up, and noticing that as the ECT went down, the CHT went up (thanks Edge), I took it down to a shop to have them check for exhaust gases in the coolant. I would have done it myself, but the kit from Napa was $50, and having the shop do it was $50, I figured I'd save myself the hassle. The service writer swore up and down that I was just wasting my money, that I just had a clogged radiator, but I told him to do the test anyway (I'd rather pay $50 for the exhaust gas test, than spending all the time to pull my radiator to be tested, just to find out that it wasn't the problem). The guy called me up later that day and said Well damn, I guess you were right.... it turned yellow in only 30 seconds, the fastest he's ever seen.

Now I just need to see whether or not it is worth it to just change the head gaskets, or just throw another motor in it (167,000 miles). It's also a gamble on the head gasket, since the head may be cracked. However, since after it warms up, there is no cooling problems, I'm hoping it is just the gasket that swells after it gets warm.

 

I would consider a crate motor with a 3 yr. warranty. With that many miles you will find other wear items such as timing chain, oil pump, pistons, ect. Don't overlook motorcraft engine, check their website for specials.