Heater Hell

[Quik8slvr]

1046287

Im having some problems with my heater, whats happening is after the engine warms up and its been running its still blowing ice cold air (cause its 20 degrees out) eventually the temp guage will read way up into the red, now if i play with the lever and switch from off to vent a couple of times and then back to heat it will start blowing hot and the engine temp will go back down to normal...anybody have any clue whats wrong? i dont have my heat on in the summer...why would my engine overheat in the winter when the heat isnt on?[addsig]

 

[bigTlilODD]

1046331

sounds like the cables are messed up. I had a similiar problem, except that my engine didn't overheat. All the way to the right, near the passenger door, is the heater box (if the set up is like my '95 YJ) If so there is a lever on the side. You can move that by hand and that should solve it temporarily. From what I've seen and heard, trying to fix the cables is HELL! Try using WD-40 on them. If that doesn't solve the problem, then they may need to be replaced. Hope this helps[addsig]

 

[jeeper411]

1046334

Exact same thing happened to my sisters suburban this week. The problem is your jeep needs water,or you need to check and see if your oil is low.Also the radiator could be clogged up. Hop your up and running soon.411[addsig]

 

[jcooper]

1046364

I had the same problem a few weeks ago with my 97. The radiator had coroded to the point it had begun leaking.

(Watch that salt air and small stones) Basically it ran real low on fluid. When this happens and air starts flowing

through the engine, the air becomes superheated (much hotter than the fluid). When it bubbles near the temp

sensor, the sensor goes in to the red.



As for why it blows cold air? I haven't thought that out yet, but mine did the same thing. Replacing the radiator

and hoses fixed it though. While you have it drained, if you can spare the cash, change out the heater hoses,

temp sensor, and thermostat. After replacing this stuff, the pressure is a little higher, and old hoses will fail soon

after an install. I did all but the temp sensor (cash flow problem). Some people recommend changing the temp

sensor after it's spiked like that a few times. Mine still works fine (hopefully).



I got the brass core radiator at radiators.com. All shipping is next day for $9. Definite step up from the plastic

core that comes stock on the TJ....



Cooper.



PS - I suspect the fiddling with the knobs then things working again is coincidental. You should see some of

the combinations of buttons, punches, and jiggling I do to get my stereo to work.[addsig]

 

[MudderChuck]

1046385

Common problem in Chevy engines, mostly with off roaders and hot rodders. The heater circuit is part of the cooling system. When the heater is plugged or the hoses removed and plugged, the motor will overheat. Most Chevs the heater is a partial bypass of the thermostrat and allows some coolant to circulate giving a true reading of the engine temp for the thermostat. Without the heater or a loop in the system it will act up. Be sure your anti-freeze is to specs. could be iceing up and do some real damage. Heater often fills up with sediment and crude, sometimes, need to be seriously cleaned. Like another guy recently reminded me, anything over about 15 PSI can damage things, 30 PSI max if you try and blow it out, with water or air. Some motors have the bypass built into the thermostat housing (Jeep) and some have a water valve, built into the heater hoses (mostly older models).[addsig]

 

[Quik8slvr]

1046388

The radiator and fluid levels are all fine, brand new radiator, all new hoses, i just did my engine swap last month, i'll check out the heater unit and see if maybe something got messed up last time i was out in the mud or when i did the swap...i know the problem with the cables because my temp slider doesnt work at all and the vent slider only has two positions, vent, and Defrost/heat about 50/50 outa the top and the bottom...has anybody found a way to tear apart the dash and fix the heater unit with something homeade that isnt a jeep product so that hopefully it wont break anymore?[addsig]

 

[Craig]

1046389

I had a similiar problem with my 93 YJ. I found the problem to be an air pocket circulating throughout the cooling system. If this is the problem, it's easy to fix. Park your jeep uphill or jack up the front end, remove the radiator cap, start the jeep and let the it run for a while with the heater cranked on hot. The air pocket should eventually work it's way up to the radiator, when this happens add coolant or water. This solved my problem hope it helps you.[addsig]

 

[MudderChuck]

1046427

Air pocket in the cooling sytem seemed to be a fairly common thing in my XJ, finaly put one of those clean out access fittings on the heater hose, helped some. Also squeezing the top radiator hose seemed to help some. Parking with the nose up hill is a good idea.[addsig]