Question-------------------------
Followup To
Question -
I have a 91 GMC Chevy Suburban.
The heater blows at all speeds and on all settings, but only blows cold air.
It is a sound vehicle and in great running condition, except the heater.
I have no clue where to even begin troubleshooting. Any help would be greatly appreciated.
Sincerely,
Michael Partridge, PO1, US NAVY
Answer -
What mechanical work of ANYKIND has been performed on the vehicle within the last 6 months ?. Do you have ANY engine driveability problems and or a MISS in the engine at idle or while driving ?.
NONE, AND NO PROBLEMS OR MISSES.
1. Are you SURE the radiator and overflow container is FULL when the engine is at normal operating temperature ?. YES
2. Are you SURE that BOTH heater hoses are HOT to the touch when set on HEAT and engine at normal operating temp ?.
THIS MIGHT BE THE PROBLEM. THE VEHICLE WAS PURCHASED 2 WEEKS AGO. I DID LOOK UNDER THE HOOD AND SEE TWO HOSES CONNECTED TO ONE ANOTHER IN THE RIGHT CORNER NEXT TO THE FIREWALL. IN THE SAME AREA, THERE ARE 2 PRONGS STICKING OUT WHICH LOOK TO ME AS IF THEY SHOULD HAVE HOSES OR SOMETHING CONNECTED TO THEM. BUT NO KNOWING IF THIS WAS IN FACT THE CAUSE OR WHAT THE HOSES GO TOO, I DID NOT MESS WITH IT.
3. Are you SURE the thermostat is operating correctly ?. YES
4. Can you physically see if the mechanical arm that opens and closes the HEATER CORE DAMPER DOOR is operating correctly. Try listening and viewing this damper door control arm for smoothly opening and closing without making any noise or SKIPPING during it's movement as you select from full A/C to full heat on your control panel. I DO NOT KNOW WHERE THIS IS, SO THIS IS ALSO A POSSIBILITY.
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AnswerThose 2 hoses are supposed to be connected to the 2 pipes that you see sticking out of the firewall into the engine compartment. These hoses are for the HEATER CORE of which is in 100% of all cases such as yours appears is that the heater core is leaking and needs to be replaced.
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