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Poor heater output


Doug Aleshire's Avatar
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02-08-02, 09:00 AM   #1  
Poor heater output

Have 1991 Chev g-10 van 4.3L no A/C - have changed thermostate 3 times, taken it to dealer to replace heater control cables and added "T" from heater core outlet hose to lower radiator hose per service bulletin. No improvment although dealer says it works fine. My dad had a Chev truck and the heater was awesome. Since I do not have a recirculating feature nor a flapper to control the amount of fresh air over heater core, is it possible that I am getting TOO MUCH cold air to reduce the heater core output? There are only 2 cables attached to flappers which both work properly, 1 for heater/Defrost and the other for Hot/Cold, both are within the cab after the heater core. Any advice would certainly be helpful - Michigan weather can get pretty cold and I come from Minnesota where the van just didn't get past lukewarm!

 
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trinitro's Avatar
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02-08-02, 10:53 AM   #2  
I have a 89 G20 and it's the same way. I think that's just the way they are...

 
Joe_F's Avatar
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02-08-02, 11:45 AM   #3  
Joe_F
Feel the heater hoses? Are they both hot? If not, the problem is in the engine/cooling system side.

If they are hot, the problem is inside the vehicle. Might have a clogged heater core.

It's NOT how the heat is supposed to be.

 
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02-08-02, 12:48 PM   #4  
My van has always been like that. I even took the heating core out and flushed it to no avail. For such as big van it sure has a very small core. It's a van also...no insulation...not very good door sill eithers. That car is not fun to drive in the winter.

 
Doug Aleshire's Avatar
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02-13-02, 05:22 PM   #5  
Poor Heat Output Corrected

I'd like to let you know that after performing a test, I was able to resolve my poor heating issue with the 1991 Chev G-10 Van, no A/C. After Joe Cool suggested that I feel hoses, I did find a slight difference in temp. I blocked the passenger side void (outside and above blower housing) which supplies air to blower and passenger side fresh air vent. Before test, Outside temp was
+18, ran van for 20 minutes, blower fan on high, placed thermometer in the defrost vent, initial reading was 134, blocking vent at 80-90% temp read 148, with no blower deficiency. I blocked duct 100% but blower did not blow as hard UNLESS I pulled the fresh air pass. vent lever. This acted like recirculation of air, like a cold air return. Force of air was great, temp went to 150. Went on the freeway....heat was great - no problems at all. Trinito said that the heater core size in his 88 van and suggested others as well were small especially for a van. Based on this, the above action has for the first time given me actual heat that I never had before and I should not freeze when it's 15 Below!!

 
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02-13-02, 08:00 PM   #6  
Joe_F
Sounds like some sort of duct/cable issue that you resolved.

Good job!

 
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