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1991 GMC C2500 Sierra SLE 5.7L Heater Core
Posted to GM Miscellaneous on 12/11/2003 20 Replies

when the engine is fully warm there is a thumping noise coming from the heater box after a test drive. no sign of overheating. can feel the vibration in the box if you put your hand on it.

20 Replies Received (View Replies)

  Related Documents & Media  1991 GMC C2500 Sierra SLE

 
Message Closed w/FIX

car Vehicle Data

1991 GMC C2500 Sierra SLE

VIN 1GTGC24K2M
Engine5.7 L / 8 cyl / GAS
Trans4-speed Automatic
DeliveryFI
AffectedHeater Core
ConditionsThumping Noise
Message Closed w/FIX

car Vehicle Data

1991 GMC C2500 Sierra SLE

VIN 1GTGC24K2M
Engine5.7 L / 8 cyl / GAS
Trans4-speed Automatic
DeliveryFI
AffectedHeater Core
ConditionsThumping Noise