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whitetailtinks
10-13-2012, 04:46 AM
i flushed the cooling system completely and addednew coolant and also changed thermostat and i still have no heat . heater core ? on 1999 cherokee 3" bds suspension lift 31" bfg allterrain :bang:
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4.3LXJ
10-13-2012, 05:18 AM
How bad was the coolant before you flushed it?
Carves
10-13-2012, 06:03 AM
How bad was the coolant before you flushed it?


X 2 ... and what other symptoms was it having ??

Waterpump and/or, blend door in the Heater/AC housing, might be part of the issue ??
whitetailtinks
10-13-2012, 03:47 PM
:bang: no other symtoms runs at normal temp coolant i took out was rusty colored but tested good
bluedragon436
10-13-2012, 03:59 PM
I had a similar issue with my 98 last year, and tried doing the same fixes you did... Try removing the two hoses for the heater core from the engine and then take a air hose from your compressor if you have one, and push air reverse flow of normal through the heater core... then fill the core with CLR or something like it, and let that sit for about 10-15 mins... then blow that out reverse flow with the air again into some sort of container like a milk jug, allows you to see how grungy it really is... and then flush water through the core a few times using the same method, and then hook it all back up and see if it helps any... it worked quite well in my case...
olds-cool
10-17-2012, 12:03 PM
My first thought was plugged heater core too. I would follow bluedragons suggestions although you may want to look into the CLR just to make sure it won't react with the metal. I saw one guy that uses bleach to flush out cores, not sure it really helps any more than good ol hot water would though.
jschmidt250
10-17-2012, 03:35 PM
Is the heater valve working? These things always seem to go out.
Carves
10-17-2012, 05:47 PM
:bang: no other symtoms runs at normal temp coolant i took out was rusty colored but tested good

Give it all a good flushing as others mention.

Might be worth getting the waterpump off ... and making sure theres enough impellor to shunt the coolant through the heater system.



Is the heater valve working? These things always seem to go out.

In what I think was an attempt to resolve clogged heater core / stuck valve, issues ... They changed the 97+ models to a constant flow, heater system.

No heater valve/taps under the hood in update models.

Instead it has a flap/blend door in the vent system - which sends hot or cool air to the outlets.

So instead of the tap/valve, not working ... or the core clogging ... The blend door usually gets stuck ... in cool air mode only .. :bang: .. :D