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hamilton5 10-01-2012 09:31 PM

heater output problem
 
My heat output is great for the first month or 2 after I flush, then it starts getting weaker down to just luke warm..

Ive flushed 4 times, once using one of those rad cleaners.. Good flow threw the heater core..

I did use the prestone and not zerex.. I think there would be more posts and problems about this if that was it?

Temps are fine, warms up ok, never overheats. Sitting at a red light, 95 degreee weather, never went over 210..

Tried a new thermostat, I really dont think its the water pump, because temps are fine, but the heat does improve if I get the rpms up. Im confused, help!

Frango100 10-01-2012 10:12 PM

Re: heater output problem
 
Are you sure that there is no air left in the heater core? No bubbling noises when you rev the engine?
I red once about corrosion/erosion which had eaten away a part of the aluminum of the timing chain cover, causing a similar problem as you described. Donīt say that this is your problem.
Can also be that the waterpump efficiency went down due to wear, but would expect higher engine temps then as well.
My first try would be removing the waterpump and check the condition. You would at least need a new seal or just change it with a new pump, to rule out this possibility.

mmorris 01-19-2014 12:23 AM

Re: heater output problem
 
Quote:

Originally Posted by Frango100 (Post 691189)
Are you sure that there is no air left in the heater core? No bubbling noises when you rev the engine?
I red once about corrosion/erosion which had eaten away a part of the aluminum of the timing chain cover, causing a similar problem as you described. Donīt say that this is your problem.
Can also be that the waterpump efficiency went down due to wear, but would expect higher engine temps then as well.
My first try would be removing the waterpump and check the condition. You would at least need a new seal or just change it with a new pump, to rule out this possibility.


Frank,
I have very little heat output in my 01 Sport. After flushing the system, I still have very little heat and I DO hear a gurgling/water noise when I shut off the engine. Does this mean I may have air in the core? Would this cause a lack of heat? If so, how do I get the air out?
Thanks, Monte

Frango100 01-19-2014 06:24 AM

Re: heater output problem
 
Hi Monte. An air pocket stuck in the heater core will (partly) block the coolant flow through the core with as a result minimal or no heat. The gurgling noise also indicates air. To get it out normally takes several heat up and cool down cycles. Running it for a while on an incline (nose up/down or sideways) could also help to get rid of air pockets.

kennzz05 01-19-2014 06:37 AM

Re: heater output problem
 
Quote:

Originally Posted by mmorris (Post 962000)
Frank,
I have very little heat output in my 01 Sport. After flushing the system, I still have very little heat and I DO hear a gurgling/water noise when I shut off the engine. Does this mean I may have air in the core? Would this cause a lack of heat? If so, how do I get the air out?
Thanks, Monte

are you aware that year has issues with head cracking and this could be causing youre heating issues there are cherokee specific forums you can find more answers just google xj or cherokee forums not sure if i can mention them so i wont.

also heres some stuff to read about the head https://www.google.com/search?q=cher...sm=93&ie=UTF-8

mmorris 01-19-2014 09:59 AM

Re: heater output problem
 
Quote:

Originally Posted by kennzz05 (Post 962049)
are you aware that year has issues with head cracking and this could be causing youre heating issues there are cherokee specific forums you can find more answers just google xj or cherokee forums not sure if i can mention them so i wont.

also heres some stuff to read about the head https://www.google.com/search?q=cher...sm=93&ie=UTF-8

Yes, I was aware of the problems before I bought the Jeep. I don't seem to have any of the symptoms, at least yet:).

mmorris 01-20-2014 11:55 PM

Re: heater output problem
 
I finally have enough heat to cook an egg!
I had decided to take the thing to a dealership to get it fixed. After reading through 37 pages of posts last night, today I decided to try ONE LAST TIME to resolve this.
Several months ago I used the Prestone radiator flush and left it in for 3 days while I drove it. I then flushed it completely for almost an hour through the radiator cap using a fitting in a flush kit. No change. After reading extensively last night, I decided it HAD to be a dirty heater core.
So I disconnected both heater hoses at the block and, using the hose, flushed extensively in both directions. I then blew (by mouth) into the inlet hose to clear most of the water from the heater core. It must not hold much since I only poured about half of the bottle of Prestone flush directly into the inlet hose while elevating it. I let it sit for an hour and then flushed it with a hose for about 15 minutes. I then repeated the whole process with the other half of the Prestone bottle and then filled the hose with antifreeze and reconnected them. Burped the system and drove it for 20 minutes. It was warmer, but didn't really kick in until I kicked in the passing gear a couple of times. Then the heat really kicked in and continued even at low speeds. While flushing the heater core, I collected the effluent and there didn't seem to be very much "junk" being flushed. But it worked!!!
Thanks to all who offered advice. I guess it helps to be persistent!

hamilton5 02-24-2014 02:58 AM

Re: heater output problem
 
heat still good after a couple months?


With my condition when I pull the core lines and drain and refill, heat is fine for a while..

mmorris 02-25-2014 09:25 AM

Re: heater output problem
 
Quote:

Originally Posted by hamilton5 (Post 981176)
heat still good after a couple months?


With my condition when I pull the core lines and drain and refill, heat is fine for a while..

Yes, my heat is still excellent. It's actually now as good, or better, than my other vehicles. Pouring "straight" Prestone cleaner directly into the heater core must have broken something loose. I only left it in for an hour each time. I was afraid I might eat a hole in the core, but was to the point that I was going to replace it anyway. No leaks and it worked like a charm.


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