Well driving home from work for thanksgiving one of the heater lines blew when i was on the free way, smelled the antifreeze, lost heat, was about to pull over when the temp spiked, shut her off and coasted onto an offramp. Got it fixed filled it with 50/50 and no heat on the way home. Thought i may have messed up the thermostat, replaced it and still having the problem, wondering if i may have literally fried a sensor, if sometging is stuck open? Etc. I have also noticed a slight whine in the engine, sounds more like an alternator problem than anything else. Its a 91 xj with ac, any insite would be greatly appreciated!

 

Could be an air bubble in the system. On a '91, it should purge over time.

 

The motor doesn't warm up or the heater doesn't get hot???? Hoses don't usually "blow" unless they r old/neglected. What has been done regarding cooling system maintenance?.....and how long ago?

 

search backflushing heater core
and purgeing air from cherokee closed cooling system, on google

 

Engine is running cool, its reading about 150 on the temp gauge, blows semi warm air, doubt it is an air bubble, but its worth a shot at this point. And as far as cooling system ive replaced the thermostat twice, previous owner didnt have one in it to beguin with, replaced the radiator and changed coolant.

 

Oh and just a little more info, the hose didnt blow, it had a hose clamp butted up next to it which over time cut into it which then caused it to fail under pressure.

 

As I said earlier, his doesn't have closed cooling system.

To the OP: Change thermostat to factory Mopar 195*. Sounds like yours has a "fail-safe" aftermarket one that is now stuck open after temperature spike. It's doing what it was designed to do.

Edit: I re-read your post. Looks like you have already replaced it, but with what kind and what rating? It seems that aftermarket thermostats have gotten more unreliable over the last several years. Which is why many of us have went back to the original. Pricey and hard to find, but the best.

 

91 is not a closed system. 90 was the last year for that.

83501426 stat from the dealer.