Squealing fan, not tires.

June 26, 2006 4:02 PM

For a friend: How would a semi-mechaically-inclined person with their own tools find, remove, clean & lubricate -OR- find, clean & lubricate without removing, the vent/AC van which is under/behind the dash in a 93-95 Cadillac Eldorado ETC?

I have a squeal that comes and goes only when I have the fan on for either the vent or the AC. Most times on smooth roads after a while it will go away, but then one bump and it comes right back. It sounds kinda clogged and not lubricated.

I'm making that assumption from 2 non-car fan related situations in my past.

1) Noisy computer power supply fan that sounded similar that I cleaned out with compressed air. Never had a problem again.

2)Noisy bathroom exhaust fan making almost EXACTLY the same noise that I cleaned out, lubricated with wd-40 and never had a problem with again.

Now when it comes to cars, I always prefer to take it to a professional. I am not a do-it-yourselfer when it comes to cars. However, I went to two places and got the following answers:

1) -my regular mecahic, whom I trust implicitly- said that he's pretty sure thats what it is, but doesnt know where the fan is located and couldnt give me an idea of how long or how much it would take because he really doesnt do interior things.

2) -Cadillac dealer - wants $600 just to diagnose it (which I would say has already been done) and started throwing around $1200 for labor and $500-$600 in parts, but he doesnt know for sure...

Ive tried a little compressed air blown into the vents with no success.

Help!

Bonus question: I've heard of something called "dry spray lubricant" What is it and where can I get it?

Thanks in advance!

posted by sandra_s to grab bag (5 comments total)

Buy the Haynes manual.
posted by unSane at 4:08 PM on June 26, 2006

One other thing it might be is the alternator belt - which can be squeaky when its slipping - possibly the AC is putting extra strain on the system and causing intermittent slippage? Other signs would be if there was a similar squealing when the car was being started. IANAMechanic, however, perhaps more knowledgeable mefites can eleborate...
posted by prentiz at 4:20 PM on June 26, 2006

What do you mean when you say, "with their own tools?" Do you have at least two jackstands? A lift? A torque wrench? A breaker bar? Real penetrating lubricant (not WD-40)? Brake cleaner? A new belt? Or do you just have a socket wrench and a phillips head?

If the fan's behind the dash, that means you have to remove the dash. That (probably) means you have to remove the instrument cluster and associated wiring. That means a royal pain in the ass. That also means a good chance at fucking things up if you don't know where everything's supposed to go. So first, get a Hayes or Chilton manual for the model year of the car. If you can get your hands on a real service manual, even better.

The only "dry" lubricant I can think of is a graphite-based lubricant, useful in situations where the parts are being used in a repetitive motion, or exposed to high temperatures, or need to resist rusting. Liquid lubricants "squeeze" out eventually, which is why you're not supposed to use WD-40 on your bike chain, for example.
posted by Civil_Disobedient at 4:33 PM on June 26, 2006

As a general observation, fan units in cars fall into two types :

• The ones that stick out like dog's proverbials and are easy to get at, and
• Ones that seem to form the seed, the core about which a car is built, and are almost impossible to get at without dismantling the rest of the car.

(There is also a 3rd type: the ones which are plainly visible, but require the dismantling of the whole car to get at. Old Jaguars fall into this category...)

In other words, it's not particularly surprising your mechanic can't give you a definite quote, and it's equally not surprising the dealer wants $1200 labour.

Dry spray lube is exactly that - a dry powder, usually teflon or graphite, in a spray can. If you were thinking of just spraying that into the vents and praying, don't! - it's really made for sliding parts, not rotating parts; it'll probably never reach the bits that need lubricating anyway; and, if it gets into electric motors, tends to make them either (a) seize, or (b) catch fire.
posted by Pinback at 4:45 PM on June 26, 2006

This is definitely a job for a good mechanic (and NOT the dealer, please). If it were me, I'd go with the guy you know and trust, or at least ask him who HE knows and trusts. Then let them poke around inside for a bit, get a quote, and move on from there.

Or, just ignore it.
posted by muddgirl at 7:44 PM on June 26, 2006