New Fan noise (at least I think it's new)

[rreimund]

I've tried searching for this issue a number of different ways, but I came up with nothing. I'm pretty sure this isn't the fan clutch issue either.

In any case, here's my dilemma. I just had a 140 mile drive this morning in 80 degree weather -and am looking forward to a 140 mile return trip in 94+ degree weather this afternoon. When I stopped for gas this morning and turned off the engine, I turned the key back on (without restarting the engine) so I could see the fuel gauge as it was being pumped (Full service station in New Jersey - you can't pump your own) In any case, I had my AC switch on and I started hearing a "thump, thump, thump" repeatedly. If I turned off the ignition key, it would stop. If I hit the AC button to deactivate it (even if the center fan control is still on) and the noise stops.

It seems to correspond to the fan that's in front of the radiator (i.e. right behind the kidney grills) The fan that's visible from underhood wasn't moving (and it's my understanding that this is the one that has the fan clutch problem on occasion on these cars.) If I keep the AC off, no problem.. except I'll broil on the way home in traffic.

That said, btw, the car is not overheating..

The noise seems like the outside of the front fan seems to be hitting or rubbing on something - but I haven't hit anything, or even done any work in that area that would result in something moving into it's path of travel.. Any ideas?

[632 Regal]

if the sound seems to be coming from no-where I wouldnt worry about it since my car has always had a mystery thumping with the key in the on position. However, if you have located the sound to be coming from the auxillary fans than you need to figure whats rubbing up there. Good luck and enjoy the summer weather :p

[rreimund]

That's the thing.. the noise seems to be coming from that front fan. It appears to be tied to that little blue A/C button. If it's off, no problem - regardless of the engine (if it's running or not).. But if the button is on, it'll turn that front fan on and it seems to bang on something. Not sure what it could be, or more importantly - what I can do about it before my drive up to NY, so that I have air conditioning.

[Ross]

That fan ought to run at speed faster than to make bump, bump, bump. More like a grind if it's rubbing. Maybe the compressor clutch is cycling on and off.
If it turns out to be the fan has bent or broken blades or the housing is somehow F'ed but the motor is okay let me know. I saved those parts from the last aux. fan I changed.

[rreimund]

Ross,
and this is the fan that's on the outside of the radiator - right? Not the fan that you can see when the hood is up.. but the one that you can only see through the kidney grills. (kinda)

[Fetch]

and it's my understanding that this is the one that has the fan clutch problem on occasion on these cars.

Just to note, this is not that fan. The fan in the front most of the car, right behind the kidney grill is an electric fan. The big 'mechanical' fan in the engine bay, behind the radiator, has a temperature activated clutch that goes bad with age.

I'm confused how the electric fan, or compressor clutch would be turning on at all while the engine is off, usually that stuff wouldn't turn on unless the engine was on.

The electric fan in front will turn on if engine temp triggers it, but you said it was directly related to the A/C button which is odd since the engine is off.

My electric fan is broken (doh!), so I can't help you with letting you know if it comes on with the A/C button w/o the engine running, and without the engine temp triggering it to be on.

[rreimund]

Yeah, couldn't tell you if it's an electrical issue or not.. I just know that if I have my ignition on, but the engine not running, my HVAC system blower will run, etc. I'm guessing the AC will run too - albeit not very efficiently.

And you're right, it's not the fan that has the common "fan clutch" that goes bad - I thought that was it at first, but that fan isn't running at least didn't run this morning during the circumstances that I observed. It was just that front most fan. I think I'm going to have to take out the grill and see what, if anything might be hitting it - since there's no other way to get a good look.

[Fetch]

Make sure to take a look at the fuse for the fan too (aux fan).

[rreimund]

Ok - before I got back on the road last night on my return trip back to NY, I figured since I was in a garage (in the shade) on this 96 degree day, I might as well take a closer look here, rather than getting stuck on the side of the road in the sun or something.

So turned out there's a U-shaped weather stripping that appears to be attached to the backside (inside) of the bumper and/or grill pieces. In any case, this weatherstripping seems to have come loose somehow and was hitting on the aux fan. I managed to remove the little cover in the lower bumper that is over the external temperature sensor next to the fog lamp on the driver's side, and reached up and moved it out of the way. Got home with AC working and without incident otherwise.. :-\

Now anyone know how to get that weatherstripping back on again? I'm guessing the bumper has to come off.. the grill piece at a minimum.