'94 Gmc Sierra

[PacaG]

Hello all ! I recently bought a '94 GMC Sierra in pristine condition,only 42k origanal miles.

This truck sat in the garage for almost three and a half years and was rarely driven. I had a tune up done , new hoses and serpintine belt etc and it runs like a clock. Just lately there has been a tapping noise coming from under the dash on the passenger side. This only occures after driving and turning the ignition off, then the tapping starts, for about 20 seconds. I felt the ,what I believe is the fan housing ? and could feel the tap from there ! Question , is there something I should do, other than going to the shop? There is alot I need to learn about this truck. Any advice would be greatly appreciated..........PacaG

[Stevens03]

I'm no help, but congrats on the new truck. Post up some photos when you get a chance.

 

As far as the tapping goes, your saying you drive it, then turn it off.. and there's still a tapping noise?

[PacaG]

I'm no help, but congrats on the new truck. Post up some photos when you get a chance.

 

As far as the tapping goes, your saying you drive it, then turn it off.. and there's still a tapping noise?

 

The tapping noise starts immediatly after turning "off" the ignition

[redjewel2ss]

so your saying its coming from the fan housing under the hood, or from the A/C box under the dash?

[PacaG]

so your saying its coming from the fan housing under the hood, or from the A/C box under the dash?

 

If you are outside the cab it sounds like its coming from under the hood on the passengers side . If you are inside you can hear the tapping under the dash, passenger side ???????

[PacaG]

so your saying its coming from the fan housing under the hood, or from the A/C box under the dash?

 

If you are outside the cab it sounds like its coming from under the hood on the passengers side . If you are inside you can hear the tapping under the dash, passenger side ???????

 

 

BUMP !

[PacaG]

so your saying its coming from the fan housing under the hood, or from the A/C box under the dash?

 

If you are outside the cab it sounds like its coming from under the hood on the passengers side . If you are inside you can hear the tapping under the dash, passenger side ???????

 

 

BUMP !

 

ANYBODY ?

[txab]

Maybe it's a HVAC door moving after shutdown, or the actuator especially if it's vacuum operated.

[Cool Zr2]

Its a mouse trying to get out of the vents.... J/K!

 

I'm sure its nothing, just drive it and see what happens, nothing in that area of the truck should be a real cause for concern.

[PacaG]

Its a mouse trying to get out of the vents.... J/K!

 

I'm sure its nothing, just drive it and see what happens, nothing in that area of the truck should be a real cause for concern.

 

Thanks for the replies . The tapping noise doesnt happen all the time, maybe once out of twenty starts and turn offs, I talked to my neighbor about the situation and he said that since the truck had set in the garage for quite some time the heater and AC should be run from time to time to keep everything lubricated. If thats the case, is there a way to lubricate and where ????

[PacaG]

You're right ! It is indeed the hvac door. I could feel it moving making the tapping noise. A gentle push upwards opening the flapper and the noise stops. For now, I wedged the flapper just enough to open and all is quiet !