Hey guys my 89 jeep Cherokee's cab wont heat up in this cold weather, It blows out warm air but no very warm at all not hot like it should. I flushed out my heater core and made sure it wasn't clogged, my heater valve is working properly its got a new thermostat and water pump. What else would cause me not to have hot air? Any advice it appreciated

 

Topped off with antifreeze? Totally full.

I'm having issues with my heater core has reduced flow; I can get clear water both ways when I clear it out but due to crap building in there is not enough element to heat up.

Been told water will calcify in the heater core.

 

What brand of stat and what degree?

 

I have the same problem on my old Jeep. I get good flow flushing the core, but pretty medeoker heat, even with the coolant at 195*

Likely I have an issue with the core, but mice...they do DO things....They did put together a team and make a few hits, (goal unclear). Sabotage? Maybe..I did have some stuff blow out my vents, (like my registration, proof of insurance ect...) I wonder if there might be a bunch of stuff in there somewhere blocking 3/4 of the core.

I did once see a "butterfly" valve where the back was all caked with deposits, so while open, only 1/2 the flow was allowed. If you do look at that BEWARE! That valve plastic crumbles easily. I might cut the old hose's if I wanted to get a look at mine.

I did a 1/2 harted treatment with CLR.....no help there. Maybe if I left it longer while it was warmer.

 

Ditch the valve and substitute a straight piece of tubing. Plug the vacuum line. Don't look back.

 

I got the stat from nappa and I belive its 195? and if I do away with the valve and spice a tube in wont it blow heat even when you turn the heat off since the valve wont close off the warm coolant?

 

You will not have heat all the time. Take it from a guy who lives in Arizona and has done the mod numerous times.

I'll bet our Napa stat is faulty and opening too soon. What's your dash gauge say?

 

Its running really cool, Its at the second dash between 100 and 210 on the temp gauge not sure how warm that is but I know it should be running warmer

 

Do you have correct thermostat and do you have jt installed the correct way?

 

Yes sir and yes it it is installed correctly.

 

I made the mistake of assuming that if you had flushed your core, your engine had been operating at temp. The valve being an issue is not likely if it looks like it's opening, and eliminating it is not supper easy. Also long ago I remember my Jeep getting too hot with no AC and the valve open.

On Cruiser's advice I'm going to swap my new(ish), Napa T-stat (both 195*), with this OEM stat...in a few tanks...

 

Does the top hose from radiator to tip if thermostats build pressure when jeep
Gets up to temp?

When you turn temp **** does the temp of air relatively change at all from cold to hot?

 

Im not too sure it it does build pressure or not, Ill have to check when I drive to work tomorrow, if it doesn't would that mean that my stat is stuck open? and yes the temp does change from cold to hot.

 

I think he means, does the hose feel hard like it's under pressure.

You might "cut to the chase" and go ahead and try an OEM thermostat. Yea a hassle and like $25 bucks, but there are allot of reasons to know for sure that that one is correct. Might be an issue with mileage as well. I'm supper tight and bought one.

If you are really in a bind you can pull it and put it in a pot of water and see how it opens. I'll be checking MY Napa T-stat after I change to the OEM.

 

Bad thermostat.