Im having an issue with the heater in my jeep barely being warm. The warmer it gets the warmer the air will get but it being Winter in Wyoming its starting to get pretty cold and it will Blow air warm enough to keep my windshield defrosted. I recently changed my water pump and thermostat and that didn't help. Before I change my heater core Im gonna try and flush my heater core and and put some clr in it before the flush. Ive seen some people on YouTube that claims Clr worked but other people say not to use it. Has anybody used clr and anything else that helped the heater core?

 

I used the standard Prestone cooling system flush. My heat has been working great this season.

 

The most effective part of cleaning out the heater core is taking the hose and flushing the crud out in both directions. Sediment tends to settle in there and clog up the passages, particularly in the lower part of the heater core. I'd do that before I did any chemical treatments.

 

First make sure your blend door is working. That might be the whole problem. How hot do the heater hoses get?

What year is your beast? Do you have the heater control valve? IF so, lose that turkey. Just replace teh lines with 97 or later lines, if you want to be fancy. OR, just buy about 4 feet of 5/8" and 4 feet of 3/4" heater hose. Cut to fit. I forget which is top and which is bottom, but it's easy to figure out on the fly. Plug the vacuum line that used to connect to the valve, and never look back.

If you are sure the blend door is working, try adding a Tide pod to the radiator, and drive like that for a week or two. Then do a flush.

If that doesn't work, try the CLR.

If that doesn't work, replace the core. A Cherokee should be able to roast you out when outside temps are around freezing.

 

The top hose is bigger, FWIW.

 

My Jeep is a 2000. How would I check the blend door?

 

When you take both hoses off the core you can squirt it out, both directions, with a garden hose (don't blast it, use low pressure).

If it were a warmer season, I would suggest after a garden hose flush of everything, a bottle or two of Royal Purple radiator flush, with distilled water, for a week or so. It's the only brand I've come across that says you can leave it in long term.
Others say use Dawn diswashing liquid and distilled water for about a week. I've never tried that.

The Prestone stuff might give you results, after a garden hose flush.

 

 

Oh, there you go. Forget the blend door. Your heater core is plugged up.

Try this - toss a Tide pod or a tablespoon of Dawn dishwashing liquid in your radiator and drive like that for a week or so, then do the flush. Flush the whole system, too, becuase anything that comes out of the heater core is going to circulate.

Might make it leak, of course. Sometimes the crud is plugging the holes.

 

Maybe I should just get it over with and put in a new heater core.

 

If you are just dieing to take the whole dash assembly apart, go for it.

 

Toss em' in there Kyle!

 

Its best to use powdered dishwashing (or laundry) soap. Liquid stuff could foam way too much and could be harder to remove from the system. Powdered stuff rinses out much easier and the best stuff seams to be Cascade, Arm & Hammer laundry super wash, Borax.... there's plenty of options and lots of info from the internets about using laundry or dish soap in powdered form. If you go the powdered route, dissolve it in warm water first.

 

Exactly, it's not like the old days when you change a heater core by lower the glove box all the way. I miss those days, now it seems every car needs the dashboard completely removed.

 

Is TSP good for this?