Little or no Heat

Hello everyone,

I'm kind of looking for some confirmation of what this could be.

I have a heating issue that started gradually since winter started. I don't know if the "Gradually" part is because it gradually got colder or the problem has been getting worse, but here goes.

1. I am getting very little heat in my 99 Cherokee, which gets worse as the temperature gets lower.
2. As an added bonus, I have a busted blower motor resistance, so my heater fan only goes to top speed, which I think just make whatever heat I get in the core disappear faster.
3. I checked my coolant levels last week, and was a tiny bit low, so I topped it off. I did not notice a problem.
4. I took it in to get my muffler repaired, and asked to get the core flushed, but they didn't want to do it because they found sealant in the coolant. Said I would need to take it to a Radiator shop to get it steam cleaned (but they didn't necessarily say my core was clogged).
5. I think the thermostat is good because I get normal engine temp. it's very stable and builds up temp as it always has.
6. I checked to make sure my trim door. I've put it to cold and back to hot, and there is a big difference.
7. When it gets very cold, like under -10 Celsius (under 15 Fahrenheit) it will only blow warm (not hot) air at higher RPM. So I need to take off, get on the road before anything reasonable comes out.

My question is, could it be

1. a bad water pump? (Would that still allow the engine to operate normally and just not supply enough flow for the heater core?)
2. Blocked Heater core? not enough flow through it, resulting in heater core flow only at higher RPM?
3. any other ideas?

ps. When spring comes around, I am planning on replacing my AC evaporator and heater core while I'm at it. I am not doing this in the freakin Canadian winter (I like my fingers too much). So if it's most likely the Core, I'll just wait until then. Same would go for the water pump too I guess LOL.

Get it up to temp and touch the 2 hoses going in and out of the heater core. They should be the close in temperature. If one is cold and the other is hot get a good flush on the heater core.

A case similar to yours.................http://www.naxja.org/forum/showthread.php?t=980383

Jasorono,
I feel for you, really i do. I know nothing about cars, but i searched this topic to deathhasta
and i do know how to search computers.

I believe the easiest thing for you to try first is to make sure that you have not got air trapped in the heater matrix. Ideally you need to "burp the system" If your not confident of doing that, Remove the rad cap and start your engine from COLD. then simply make sure that you just keep topping up the rad with coolant as it spills over.
I searched many sites and this was the main result that i came across (associating increase in RPM with heat). I had red hot heater hoses in and out, (as did others) but i still somehow had air trapped in there.

Another popular fix i found was theremostats not operating correctly, even if they were new, cant explain it, just saying what people said fixed there problems.

Next you wanna be sure that you have not got too much concentrate of coolant in your system (too thick for the water pump to handle at normal revs).
Another, Worn out water pumps that had erroded impellas.
these are what people said caused there lack of heat from low rpm/idle.
You say that you noticed you were low on coolant, maybe you have a leak from the water pump, as i understand it they start to leak when they near the end of there lives via a tiny seep hole, but id check the easy stuff first.

PLEASE update with how you get on

dunbad said:

Jasorono,
I feel for you, really i do. I know nothing about cars, but i searched this topic to deathhasta
and i do know how to search computers.

I believe the easiest thing for you to try first is to make sure that you have not got air trapped in the heater matrix. Ideally you need to "burp the system" If your not confident of doing that, Remove the rad cap and start your engine from COLD. then simply make sure that you just keep topping up the rad with coolant as it spills over.
I searched many sites and this was the main result that i came across (associating increase in RPM with heat). I had red hot heater hoses in and out, (as did others) but i still somehow had air trapped in there.

Another popular fix i found was theremostats not operating correctly, even if they were new, cant explain it, just saying what people said fixed there problems.

Next you wanna be sure that you have not got too much concentrate of coolant in your system (too thick for the water pump to handle at normal revs).
Another, Worn out water pumps that had erroded impellas.
these are what people said caused there lack of heat from low rpm/idle.
You say that you noticed you were low on coolant, maybe you have a leak from the water pump, as i understand it they start to leak when they near the end of there lives via a tiny seep hole, but id check the easy stuff first.

PLEASE update with how you get on

Click to expand...

So Dunbad, I take it no progress in your case? It's crazy that so many issues don't have a straight answer. Bad heat, no engine power, to name a few. At least you're not in freakin Ottawa.

Oh i forgot, check the tension of your belt. This got mentioned a few times. I cannot recall it being a fix but its something thats easy to check.

Winterbeater,
we had under 15 farenheit here in the uk this week so i know how the guy feels.
Mine is still blowing red hot from all vents at idle. I know now that my drivers side was not blowing as hot as it should, but now it is.

The guy who posted his mixed heat problem a few weeks earlier (think it was "weird heat" problem or something like that) it appears that he had air in his system too. How that should effect flow rate or throwing out heat in different vents ive got no idea, but, touch wood im still good. I was gonna leave it another few days before committing to saying that its fixed

dunbad said:

Winterbeater,
we had under 15 farenheit here in the uk this week so i know how the guy feels.
Mine is still blowing red hot from all vents at idle. I know now that my drivers side was not blowing as hot as it should, but now it is.

The guy who posted his mixed heat problem a few weeks earlier (think it was "weird heat" problem or something like that) it appears that he had air in his system too. How that should effect flow rate or throwing out heat in different vents ive got no idea, but, touch wood im still good. I was gonna leave it another few days before committing to saying that its fixed

Click to expand...

That's bizarre, but good to know. Maybe the heater core had air pickets in it that would not conduct the heat and then maybe the heat coming off the different areas of the heater core was somewhat directional to the different vents. Maybe, maybe?????? Good luck, hopefully you're fixed. Knock on wood!

i had the same problem on my car i had good engine temp but poor heat.. my cause was the heat/cool flap under the dash woundn't close... and my heater core was dirty..