[JBeezy]

I have a 02' Mustang GT Convert, I have a knocking noise coming from under the dash from what seems to be the ac/heater blower motor?? I have taken it apart and put it back together thinking maybe it was not all the way tightened, but the knocking noise is still there. I know it's not coming from the engine either because the noise is only heard inside the vehicle. Has anyone else experienced this same problem or know what I'm talking about??? Any help or information would be greatly appreciated!!! Thanks

[mdvaldosta]

It's real tough to diagnose something like that without being there, tracking down noises that aren't common is very difficult.

Does the noise only happen when the blower motor is running (AC or heat on)? If so is it louder when the fan is on high?

Does the pitch or speed of the noise increase or decrease with engine RPM or speed?

[JBeezy]

It's just a knocking noise, whether the ac is on or not. I was hoping someone on here would know what I'm talking about, because had someone experience this problem as well he/she would know exactly what I'm referring to. But thanks.

[mdvaldosta]

Possible engine or transmission mount loose, or header hitting something underneath the car? Both those sounds would be there at idle but would likely go away once you got moving.

[lemon]

does it happen on bumpy roads? i get a clunking/clanking sound from my right front wheel assembly when driving. ( 99 gt vert ) im still not sure what it is though. took it to the high school shop today... found out i got an alignment issue ( tire sidwall to tread area portion had a slit... ) so i just changed the tire...

prolly gonna get an alignment tomorow...

[JBeezy]

Originally Posted by mdvaldosta Possible engine or transmission mount loose, or header hitting something underneath the car? Both those sounds would be there at idle but would likely go away once you got moving.

That actually sounds pretty logical considering the only time I do hear it, it is at very low idle. Thanks!

[99mustang232]

is it the sound of catalyst, not sure if you still have the cat's on your car or not (usually more of a rattling sound but could sound like a knocking)?

another though is smog pump not sure if your car is equiped but this is something that also activates at idle that can produce a knocking noise?

[65Stanger]

I have a '65, and I have a noise that sounds kind of like... a bit of a thumping. Only basically when coming to a stop, but then it stops at idle. Haven't figured it out yet. Doesn't really sound like an engine knock, though. Any info on that might be helpful. Your problem does sound like a mount issue though. Get some new motor mounts put on there, and once you do, let us know the result.

[Casper98GT]

Jbeezy, you have to understand what noise can travel and WILL travel. Just because you hear it inside doesnt mean its not engine/trans related. What you need to do is open all doors, and hood and even trunk. Then go around and listen to where the noise is most perdominate. Then go from there.

Another thing is i would suggest going to the TSB section of the 4.6 forum and check in there for any kinda TSB's you might think it is.

[Casper98GT]

Ok, i just checked and since you drive the car and we dont. I looked for things you suggested. How is this :

04-5-3
CLIMATE CONTROL - RATTLE NOISE FROM INSTRUMENT PANEL VENTS - DIFFICULT TO ADJUST
NOISE - CLIMATE CONTROL - RATTLE NOISE FROM INSTRUMENT PANEL VENTS - DIFFICULT TO ADJUST

[Goldstallion]

Could the problem be a ticking type noise coming from the purge valve selenoidthat can be heard more at idle or lower cruising speeds