Commonsense-less......Thought I'd share...

This is something that happened to my wife's ZJ, SORRY...but a common issue in Jeeps none the less... Prior to leaving on a fishing trip to Mammoth Mtns earlier this year I had the radiator flushed, and the coolant looked good. There was no rust or corrosion in the radiator so didn't think it was an issue. I also replaced the T-stat with a 185* T-stat.
Anyway, I drove the entire 5 hours to Bishop with no issues of overheating, the temp guage read 210* all the way...cool right??

However trying to go up the steep grade from Bishop to Mammoth the jeep started to severly overheat, so I just ended up turning around and spending my fishing trip in Bishop instead (Luckily there was good trout fishing in Bishop that weekend.....)

For the last few months the Jeep drives fine on the hwy, and around town never goes over 210*. But this past weekend I had to drive up a slightly steep hill and it started getting really hot again, 240*+.

So I figured I'd do a major tune up, including flushing the coolant system on the jeep, I also purchased a Hayen H/D fan clutch. The one in the jeep is still really tight but figured I'd replace it with an H/D anyway to see if if the temp gets any better.. Anyway in order to get the fan shroud out easily I had to take apart the front grille and radiator cover thingy... So once everything was out of the way I figured I'd blow through the radiator fins with my compressor... I could see some bugs and small rocks in the fins but nothing that looked really bad. But once I started blowing out the fins... I was shocked at how much junk was coming out... it was blowning out a lot of CRAP! Dead bugs, dirt, and debris that just accumilated over the years. I also unbolted the brackets that hold the radiator and a/c condensor together and found even more build up in between... It looked like a bunch of dead mice!!! But it was just dirt & debris that built up between them over the many years. So I filled the radiator back up started it and now it runs at 185* instead of 210*... I've yet to try up any steep grades but I feel confident this was the major cause of my problem... Sorry this is so long but I figured I'd share for those that may have a similiar issue their jeep....... But man what a difference this has made!

ScottyDog

Yeah, you will be suprised all of the crap that gets gunked up in a radiator over the years.

x2.

Sometimes, the condenser coil will develop a leak and clog the radiator with a mixture of compressor lube and road grime mix. That's also a common senerio.

Ron

I had mine rodded out last summer and they replaced the cheap plastic end tanks with copper tanks. As mentioned by Scotty there was a mass of bug guts and other debris in the fins. I think it should be cleaned out about once a year. That is my plan, to keep it running cooler. Mine is 17 years old and I hope to drive it til I die.

I've run into that a couple of times, my 2.8L S10 was the first, it would run and idle fine then out on the hiway would start to get hot. Unbolted the radiator and tilted it back, the crud that was in between the rad and condenser was unreal. I about a quarter filled up my 5 gallon shop vac with bugs, leaves, paper, feathers, some dead and dehydrated mice and little meeses plus their nest makings that they used my hood liner to construct. All it would take was the right suction to loft that crap up into the radiator face, then when you shut it down all that crap would drop back off.