YJ Heater not working..

Gunnar, maybe your heater core is plugged. It works just like the radiator but with smaller channels that can become clogged. Disconnecting the hoses to it (one lets hot coolant into it, the other lets it out) and flushing it out backwards with a hose is the usual fix. There's also a valve that regulates how much coolant flows into the heater core which is how you set how how the heater is supposed to get. Follow the control wire from the temp control and you'll find the valve. Make sure it's working.

Jerry

Gunnar wrote:

I will add to Jerry's good advice and say that you should also make sure the heater lines themselves do not run up higher than the radiator if possible. If they run higher, they can air lock and that will radically cut down on inside heat.

If you actually do only get up to 150, then you should change the thermostat. A 195 is supposed to force the engine to heat up to 195 before it allows flow. The t-stat is located where the top rad hose joins the engine under the first fitting. You will likely have to buy the gasket separate for it. Not expensive. They are not hard to do, but watch you don't bend the main top rad hose too much if you have a plastic rad or the rad top will start leaking.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

Touch the upper radiator hose after the Jeep has been running for a while. If it isn't hot, your thermostat is stuck open. If it is hot, your heater core is plugged or the valve is stuck shut.

FWIW, my '93 doesn't have a heater core valve, so if you can't find one it might not be your eyes.

I have a '93, 4 CYL as well. I had to replace the heater core about a year ago for the same reason. No Heat. It's not really that tough a job and it sure made a differnce when we went to the tops of the Colorado Mountains last Thanksgiving. Above 8500 ft and snowing like the dickens we stayed warm and I have a rag top.

I would follow the previous advice on flushing the unit first to see if that takes care of your problem. That could be the quick fix.

BTW, mine doesn't have a "valve" anywhere that I could fiind. If someone could post a link to a pic I would appreciate it.

JL

I had a 79 CJ that would not warm up the water in winter even with a higher thermostat. I partially blocked the radiator and that helped, not that the CJ had the best heater. Buy a TJ, great heaters.

Andy

2001 TJ

My 93 YJ (I6) does not have a heater control valve either. Someone else (different thread?) posted the same about their 93, so chances are good you do not have one.

The one in my wifes 95 XJ is located near the firewall on one of the heater hoses and has a vacuum hose actuator. It is about the diameter of a half-dollar and approximately 2 inches tall.

Thanks alot, at least now I have a few options to try. Again Thank You, and have a safe and happy holiday.

You are welcome. I for one would be interested in hearing what the results are.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

I'll keep you posted, my neighbor and I are going to look at this weekend. Thanks alot, matt