Originally Posted by D0dgeRam1500
I have a new radiator and overflow, they are designed for the Cherokee but are aftermarket. Are you sure that cap will work with my setup?
If your radiator is in need of replacement anyway, go ahead and put them both on. This will probably fix your problem because it sounds like you're having the same problem I had on the '89 and '90 both. What I finally found was the problem on the '89 was the expansion and contraction of the overflow jug had warped the neck so that even a new cap wasn't sealing properly and once it warmed up it wouldn't hold pressure which caused it to overheat. So when I started having the same trouble with the '90 I immediately replaced the jug.
Also in another post you said your fan was belt driven. Does that fan sit in the center of the radiator or toward the passenger side. If it's not in the center your actually supposed to have an auxiliary electric fan beside it.