Trasborg's Kaiser M715 - Universal Jeep Cooling

One of the most basic problems: Does your radiator cap still have the chutzpah it needs to keep the cooling system adequately pressurized? Without a decent radiator cap, the answer is most likely no. With no pressure, even a cooling system in perfect shape will boil over. Have your cap tested if you're boiling over and your gauge reads normal.

Ever work on your Jeep over the winter? We have. One summer, we ended up with an overheating Jeep and a lot of head scratching. After replacing the water pump, thermostat, and flushing the radiator, we realized the lights we added for nighttime winter wheeling were blocking airflow. Remember that next winter when working on your Jeep.

The first step in diagnosing a cooling system is checking the coolant/water mix. Is it clean? Is it green? Make sure it's not rust-colored or that it has oil floating in it. While you've got the cap off, check the radiator cores for blockage. Check out the article "Cool Her Down" (Sept. '05) if you aren't sure what that looks like. If the radiator core is blocked, run a flush through it. If there is buildup in the radiator, chances are the engine has blockages too. Make sure you've got the correct 50/50 water/antifreeze mixture.

Admittedly, this was toward the end of the overheating battle. The old flatfender Jeeps had vents cut in the inner wheelwells to assist with cooling, and everyone we talked to with a big engine in an FSJ cut holes in the hood in one fashion or another. We couldn't bring ourselves to cut the hood up, so the fenders got fish gills. The point is, if you've got a huge swapped-in engine or a high-output engine, sometimes the air the fan pulls through the radiator needs an outlet. If you still have the stock engine, it shouldn't have a problem, so look elsewhere.

Part of alleviating heat in the engine compartment was applying Thermo-Tec Automotive's Cool-It header wrap. It took us two days to install, thanks to the long tube headers and really tight clearances, but between that and the fish gills, we saw an improvement. Again, this is a swapped-in-engine-toward-the-end-of-the-list thing-unless you just like reduced underhood temps.