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Climate Control Problems (Air Conditioning, Heat) - All Cars

831 messages,  Last post on Aug 27, 2012 at 12:15 PM

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What is this discussion about? Heating / Cooling

Messages Page 81 of 84

#792 of 831 2001 Tahoe heater that blows lukewarm air by wolferman1

Dec 30, 2009 (7:35 pm)

So far,the mechanics have changed the thermostat, flushed the coolant 3/4 times, raised the front of the vehicle to remove air bubbles, replaced the fan clutch, replaced the temp actuator, replaced the inside filters, replaced the control switch panel, blew out the ducts, made sure that the coolant level was high enough, and who knows what else and still lukewarm air comes out of all positions. Help!!

#793 of 831 Re: 2001 Tahoe heater that blows lukewarm air [wolferman1] by imidazol97

Dec 31, 2009 (7:23 am)

Replying to: wolferman1 (Dec 30, 2009 7:35 pm)
Since they replaced the actuator motor for the blend door, I assume, assume they checked the movement of that blend door to be sure it was able to move completely to the setting sending all air through the heater core?
 
Then it's down to how hot is the heater core? Are hoses to the heater core after driving 15 or more minutes so the engine temp is full hot both very hot even after the blower motor has been on HIGH for several minutes with the motor idling? That would indicate full flow through the core.
 
Otherwise, my next step would be a heater core flush using only its hoses to gently, gently move air and water through it backwards and forwards. If the DexCool or other coolant weren't changed in 9 years there may be some goop clogging the tiny water channels.
 
Good luck. It's down to scientific analysis of symptoms.

#794 of 831 Re: 2001 Tahoe heater that blows lukewarm air [imidazol97] by wolferman1

Dec 31, 2009 (3:22 pm)

Replying to: imidazol97 (Dec 31, 2009 7:23 am)
The coolant has been changed at least once a year for the last five years. The blend door is working like it should. The coolant hoses are hot going in and coming out.The blower is also blowing a lot of air. Help again..

#795 of 831 Re: 2001 Tahoe heater that blows lukewarm air [wolferman1] by kiawah

Dec 31, 2009 (3:43 pm)

Replying to: wolferman1 (Dec 31, 2009 3:22 pm)
I suspect you are not getting air flow thru the heating core, some sort of air blockage.....or the damper that brings in outside air is stuck open, bringing in too much cold air.

#796 of 831 Re: 2001 Tahoe heater that blows lukewarm air [wolferman1] by obyone

Dec 31, 2009 (4:09 pm)

Replying to: wolferman1 (Dec 30, 2009 7:35 pm)
flushed the coolant 3/4 times
 
Did they do a back flush? That would usually clear any blockage in the block and heater area. If they did, it makes no sense that they do it 3 to 4 times which is already suspect. Also raising the front end of the vehicle to remove air bubbles sounds like something click and clack would do.
 
One thing you could do now is to check the overflow tank and make sure it is at least filled to the cold line. If it is then check the radiator to see if it is topped off. Please do this when the motor is cold.
 
Other than that you may want to change mechanics.

#797 of 831 Re: 2001 Tahoe heater that blows lukewarm air [wolferman1] by 0patience

Jan 11, 2010 (5:32 pm)

Replying to: wolferman1 (Dec 31, 2009 3:22 pm)
The coolant has been changed at least once a year for the last five years. The blend door is working like it should. The coolant hoses are hot going in and coming out.The blower is also blowing a lot of air. Help again..
 
If you have heat at BOTH coolant hoses of 150+ degrees, then the blend door is NOT working properly.
If the blend door is not shutting all the way, it allows cool air from the A/C core in the heater. Which cools the air down.
 
How did they determine that the blend door was shutting completely?

#798 of 831 Inspecting AC system on vehicle before summer months by techman41973

Jan 29, 2010 (7:47 pm)

I owned my Honda Accord for over 12 years. 3 of these years, I was caught off guard when my AC
 system was less than adequate when the summer months hit. The best example was when I was driving to Las Vegas
 in 116 degree weather and discovered the hard way that my AC was'nt up to the job. One year it was a problem with the
  evaporator, the two other years it just needed a refrigerant refill.
   I would like to prevent these suddent discoveries in the future. Before the summer months hit, I will ask my mechanic
    to inspect the AC system. Should this be done every year? Can this be done when the weather is still cooler? What
    specifically should I have my mechanic check. How many hours of labor should this cost me?
   Thanks

#799 of 831 Re: 2001 Tahoe heater that blows lukewarm air [0patience] by imidazol97

Jan 29, 2010 (8:00 pm)

Replying to: 0patience (Jan 11, 2010 5:32 pm)
Are both heater hoses so hot after the car's been running for 20 minutes and more that they are too hot to hold with bare hand for more than a few seconds?
 
Also with the blower on a high speed, and the heater set for HOT, the hoses should be nearly the same temperature. If one is cooler, that means the flow of coolant is not fast enough to keep it from losing too much heat to the air flow to really heat the air to maximum.
 
Low flow could be partly clogged heater core. Did it have DexCool when new? (Yes) Was other green antifreeze, old style green added? If so the coolant turns to globs and looks thickened in the reservoir. Professional flush.
 
Water pump may not be moving coolant properly? Open the radiator with the engine cooled a few minutes to relieve pressure on the system.Then start the motor and see if you can get the coolant to flow noticeably from the high pressure hose when someone accelerates the motor. Or you can accelerate it with the engine end of accelerator cable at the throttle body. It may take a few minutes for the thermostat to open again as the engine warms.
 
Most likely your blend door isn't closing all the way, if the first two are okay. My understanding is that all incoming air goes through the AC evaporator. Then a door forces none, part or all of the air to go through the heater core. If the blend door doesn't quite close all the way, some 30 deg outside air mixed with the air that does get forced through the heater core really cools down that air at the vents.

#800 of 831 Re: 2001 Tahoe heater that blows lukewarm air [imidazol97] by obyone

Jan 30, 2010 (12:30 am)

Replying to: imidazol97 (Jan 29, 2010 8:00 pm)
'01 Tahoe came with dexcool.

#801 of 831 Re: 2001 Tahoe heater that blows lukewarm air [obyone] by imidazol97

Jan 30, 2010 (6:24 am)

Replying to: obyone (Jan 30, 2010 12:30 am)
>came with dexcool.
 
Yes, it did. I was hinting around to suggest someone had put in standard green antifreeze and caused the DexCool to glob up. Another factor is the DexCool may not have been changed at 3 years or earlier, like some suggest. In a few cases, just like with any antifreeze left in too long, strange things begin to happen as chemical components wear out.
 
A few people have had heater cores blocked partly with the globs of crud.

Messages Page 81 of 84

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