Yeah but one day you will have no heat, and it will be the middle of winter, and the coldest day.......Murphs Law
2001 Tahoe Weak Heat
- Thread starter Bedore
- Start date
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Yeah but one day you will have no heat, and it will be the middle of winter, and the coldest day.......Murphs Law
Hey Everyone, I been gone for awhile. Nice to see everyone still giving great advice. I had the same problem and I backflushed mine in December. Saw a quick blurp of something flow out of the heater core tube. Kept the water going a little longer. Put everything back together and its been fine ever since. I guess I got lucky. Doesn't hurt to try. Good Luck.
The garage flushed the coolant again, and replaced the t-stat. Heater is working a little better, but I still do not think it's anywhere near where it needs to be. I am still getting very little heat at idle, and get somewhat decent heat above 3k RPMs, but the RPM's do not get over 3k much during regular driving. Correct me if I am wrong, but shouldn't the heater drive me out even at idle?
At this point I am certain it's the heater core, and will be dropping the truck off Monday to have them replace it.
At this point I am certain it's the heater core, and will be dropping the truck off Monday to have them replace it.
Nothing yet; they did the coolant service Friday, and they told me to call them Monday if it did not work. The dealership I bought it from will be paying for it, since I just got it.
chauncey0337
Full Access Member
My 2000 nbs tahoe was doing the same thing. I used to squeeze the heater core hoses going into the firewall to get it unplugged but that only worked temporarily so now I'm in the process of flushing my system. I did the back flush then put in Prestone super duper heavy duty flush. Now I have to put on 6 hrs of drive time, reflush, then refill coolant. In some cases just backflush is not enough so that's why I wanted to do the extra heavy duty flush.
At least I am not the only one with the issue...we can share the misery. That said, this cooling system has been flushed twice, and the core backflushed with a strong solvent, with no change in heater performance. It really suffers at idle.
For those here with a working heater, how much heat does your truck put out at an idle?
M3PO
Full Access Member
'06 Denali with 90k, it pumps heat out. Obviously the truck is big and takes a couple minutes to heat up and heat the entire cabin, but the temp blowing out of the vents is almost hot, but not HOT like many of the smaller Japanese cars I have owned.
---------- Post added at 07:15 PM ---------- Previous post was at 07:12 PM ----------
Just an idea; maybe you could use one of those infrared heat guns to measure your heater core temp. If the core is hot, then you have a vent/control problem; if it is not hot, you have a tstat or flow problem.
I don't know, I am not a tech, just a thought if you or a friend has a temp gun around.
You could also measure the temp sensor and make sure the dash is accurate.
All I know is that before it went on the fritz the heat was fine owned it since new. After the heater core was replaced it worked like it did when new.
Tahoes do take a while to warm up. Considering the volume of the passenger compartment compared to a car, or pickup truck. Thank god for the addition of rear heat. Some of the old blazers or suburbans never warmed up in the back in the dead of winter.
An IR gun would not do much good since the heater core is buried in the passenger dash area can't see it from the fire wall under the hood only the supply return connections.
Basically feel the hoses when warmed up. If the return is not as warm as the supply no flow = plugged heater core.
Well, just an update. Took it back to the garage and they still claim there is no problem with the heater core. The heater works really good when it's set to recirculate, but when you use the other setting to blend outside air in, the air is not as hot. Should I always be using recirculate for anything but defrost? It does seem like the efficiency begins to fall off the colder the outside temp is....any idea why?
When feeling the heater core lines, the inlet is very hot...will burn your hand. The outlet is hot as well, but not as hot as the inlet. Is this as good as the heater gets, or should I consider a second opinion?
When feeling the heater core lines, the inlet is very hot...will burn your hand. The outlet is hot as well, but not as hot as the inlet. Is this as good as the heater gets, or should I consider a second opinion?
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