98 Mustang Heater core tapping noise..HELP!!

[UltraKla$$ic]

I have a 1998 Mustang 3.8L Automatic. The issue is a tapping noise coming from inside the heater core "box". It is heard inside the cabin of the car and it happens only with a slight acceleration. The tapping noise goes away when you let off the gas.

You can put your hand on the outer shell of where the heater core resides from inside the car and feel something tapping when the noise is audible. It is driving me crazy and I just cant figure out what could be causing this noise.

The tapping noise DOES NOT go away when you actuate the difference vent settings...ie..defrost, max a/c, vent..........regardless of fans speed and vent setting, the tapping is consistent as described, low rpm acceleration only.

Lastly, do you guys know where I can download a 98 Mustang Service Manual? I've been using the AutoZone site, but it's kinda generic.

HELP!!!!!!!

 

[UltraKla$$ic]

FIXED!!! Thanks!

 

[atlanticblue98]

go to an auto store and buy a "Hayne's" repair manual. they are for 94-04 mustangs and it is the best 18 dollars ive spent for my car

 

[GDTrumbo]

Without a doubt!!

GT