98 Heater Problem

[Rborassa]

New thermostat, New radiator cap, engine temp great, heater hoses hot to touch, when air is blowing out of vents (all vents) air temp is not hot just warm. Seems to be mixing with cold air. It is a manual blender that seems to be functioning correctly. What do you all think?

[cromulent]

I think I am having the same problem with my Jeep Cherokee Sport. I just get cold air when I turn the heat on. I think the problem may be that line going into the heater core may be clogged.
I have been turning on the engine and then squeezing the two heater hoses one at a time as fast and as hard as i can to try to move stuff around in there and it has been kinda working to get heat for at least a day or two before it clogs up again.

[Saudade]

2 noobs for the price of one.

Rborassa. You likely have a blend door problem The temp knob controls a motor that move the flapper style door around and mixes the air. It's a common failure. If you search for blend doors, you'll find lot's of hits. Make sure you focus on the one for 97 and up. Before that, they were cable operated.

Cromulent. Sounds like you need to flush your heater core and possibly the entire cooling system..

[ironman2712]

it's look like heater core is clogged with all shit so this is what you do:
-first you pop up the hood and locate two hoses going into and out of heater core through fire wall( passanger side , very top, wright next to the coolant exp bottle-reffer to manual to locate them)
-once you find them take both off (some ammount of coolant will flow out-no worries)
-now what you need to have is-garden hose(water suply), sillicone hose about 2m long( diameter same as heater hoses- very important) and bucket
-cut about half a meter of silicone hose and conect tightly with water suply(garden hose)
-conect other piece (longer that left) to outlet of the heater core and place loose end inside bucket so you dont mees engine compartment
-now conect garden hose with sillicone end to heater core inlet, turn the water on and watch
You will notice all junk comming out of heater core,,,wait a minute,then swap ends( longer to inlet, fresh water to outlet) and keep doing like that until no junk is coming out
-after you finish-reconect all hoses to heater core as they were before and top-up coolant if neseceary
It took me about 30 minutes to flush the core and now i can drive in t-shirt in minus 30 outside
Good luck

[cromulent]

Thanks, I will give that a try. I have heard of that but it has just been too cold (ironically) to do it. My squeeze method seems to be working for now.

[ironman2712]

yes i know, but the faster you get that done the more enjoyable ride you will get during this winter, hope that helps

[Saudade]

All you're doing is breaking up the clog a bit. Once it normally circulates, it clogs again. Bear in mind that the crud is now traveling elsewhere in your system and can clog up the radiator as well other passages. It may become much more effort and expensive to deal with.

[fredjacksonsan]

Agree with Saudade and also on breaking up clogs. I'd suggest that after flushing the heater core to get it flowing again, a complete system flush with fresh coolant is in order. (There's a pretty good Prestone kit available at most auto parts stores)

I've always changed my coolant by draining and refilling the radiator every 18 months and NEVER had a corrosion or clog issue, even though some of my vehicles were over 20 years old. I'd recommend the same for everyone.