O I have a 98 cherokee xj my heat doesn't get all that warm and it takes forever. I have replaced the water pump/gasket , thermostat, belt, new coolant, flushed heater core ( just hose water tho) but still just warm air the blend door seems in working shape and you can hear it flip back and forth. No vac leak I know of if It had one the heat would be coming out the defroster n back n forth. I don't know what it could be do I need a heater core , or maybe flush it with a cleaner? What's the best cleaner to put through a heater core?

 

Some have used CLR....
Try this it may take several times to get it clean. Lots of work to remove/replace heater core. Good Luck

 

What if I let seafoam sit in there a bit or is that too strong n not a good cleaner?

 

Seafoam is for the engine(carbon, gunk Etc), heater core has rust and other forms of gunk.

 

I read somewhere (thought it was here or NAXJA). A guy ran some vinegar in his system for about 30 minutes. Then drained it. Filled it up with water and baking soda to neutralize the vinegar. Reported his heater worked better than ever. I never tried it but we been debating doing that to my buddies wrongler.

 

I use vinegar 50/50 mix, for the whole cooling system.

 

Wait are you saying flush the heater core with vinegar or actually run it in my system for 30 min then flush the whole thing and 50/50 with what water?

 

my heat was not getting as hot after the heater core was replaced(It leaked antifreeze inside the cab and no heat inside) So I changed the thermostat now it runs normal temp. I do however need some part that has to do with the blower, you can hear it go from the face vents to the top vents if higher than two. I think it has to do with some relay part, need to order from dealer.

 

If you dont mind draining all the coolant, run 50/50 water/vinegar for 30mins at least let get up to operating temp for that long. Drain mix water/baking soda run it through for a few minutes, drain, then flush heater core with the water hose again. refill with coolant.