altarchsa

Well add me to this list as of yesterday.

A/C, including fans, quit and I thought it was low on refrigerant. When I checked it with a gauge it was actually overfilled. After reducing the pressure, I went to the fuse box and found the 25a A/C blower fuse burned. I put a new one in and with A/C switch off, switched the key on without starting the engine. The blower(s) ran for about 5-10 seconds then blew the new fuse. This, and the fact that the fans have been chirping for as long as I can remember, lead me to believe that one of the fan motors froze up.

Good thing that we had a cold front come through and drop the temperatures Tuesday. It had been 100-101, but today we're down to 97. Tomorrow I'll try the bearing lube approach first and hope that I get good results. Can't live without the A/C since this is my DAILY daily driver after my wife totaled my King Ranch F150 a couple of months ago.

Just wanted to add that regarding the R&R'g of blower motors question (per the previous post), I did that once to the rear heater blower in my '75 S. The brass solid bearings had worn so much that the fan wobbled and caught on the housing, blowing the fuse. I went to a U-Pull-It salvage yard, disassemled American and Japanese car wiper motors until I found one with bearings about the same size (I think it was the 4th or 5th one). The inside diameter was a little tight, so I bored it out with a drill, installed it and the fan worked great until the car wore out.

This job should be a snap compared to that. I never start a job now without referrring to Rennlist first. Thanks to everyone who has contributed to this perennial thread.

crg53

WD #40 is a "Jack of all trades, master of none" it will fix certain problems for a short period of time until it dryes up, but considering the work involved in R & R of the A/C fans, I would choose a proper lubricant, something designed for exactly that purpose. You can use antiseize or oil whatever you prefer, but give it time to soak in, that is the trick for a long lasting fix.

altarchsa

$22.00 for small can of spray anti-seize at NAPA!!!!!!!!!!!!!

About 10-20% of a new blower motor?

Metal Guru

More like 3%.
You can find it cheaper than that on Ebay.

altarchsa

New evap. blower motor is $279 on eBay. That makes it the spray almost 17%, not counting shipping of either.

I've been shopping for a right side replacement motor. Update on cost:

Used: $125 to $275. (Most dismantlers are out of stock.)

New: $279 (motor only, eBay) to $800+theskysthelimit.........

Pays to shop!

Gregg-K

To me, the main problem of buying a used blower motor is whether it would be any better than the one that failed in my car.

... Gregg

altarchsa

That's always a concern, but I think the bearings drying out and seizing, causing the motor to burn out, seems to be the real problem. I'm betting that if I lubricate the bearings on a good running used replacement, this $800+ little motor will last longer than I do.

If the replacement does fail, it's pretty easy to go back in and replace it again. It's not difficult, like a compressor or hose that require special tools, or a clutch that's hard to get to.

altarchsa

Used motor on the way from Canada for $120.

Gregg-K

The blower's bearings are sintered and charged with lubricant at the factory. When those bearings get noisy, that means the lubricant has disappeared and/or the sintered surface has been "smeared" by friction. Once it's smeared, a sintered bearing will no longer accept lubricant.

A bearing in good condition, still with a permeable surface, will however accept lubricant, and it is good operating procedure to heat the bearing prior to soaking in heated lubricant, to facilitate this. After soaking for a period, the bearing is allowed to cool, still immersed in the lubricant.

To give an idea of the smearing problem, one should not even ream a sintered bearing, out of concern for smearing its bearing surface. Sintered bearings are manufactured to a given size, ready for use. I've been down this road many times with sintered turntable bearings, and any attempt to lubricate has proved to be a temporary bodge at best.

Hope your motor from Canada is new enough to accept a new charge of lubricant.

.. Gregg

altarchsa

Very technical response Greg. Seems you realy know what you're talking about. While I've designed a 255,000 sf metal tool manufacturing faciility, I have to admit I had to look up sintered, and then agglomeration, in the dictionary. There wasn't even a good definition of agglomeration in the on-line dictionary I used.

Thanks for the education. I'll lubricate the bearings as you suggest. I'm still betting the $160 (or $700+ from Pelican, Vertex, etc.) savings between a new and used motor will pay off.

johnbtrask

Just an observation. It seems like most of the posts re fan motors come from regions with more extreme weather. The 993 added cabin filters ahead of the blower motors. I wonder if that cut down on the incidents of failure to the bearings?

Jeff Curtis

My vote would be NO, the bearings on the fan units are sealed.

Are these the same units as for a 993? I guess they might be?

Gregg-K

Jeff,
The bearings I have seen on Porsche fan units have been open sintered bushings ... no seals at all.

... Gregg

Jeff Curtis

Yeah, I dug out an old burned up motor the other day - I think you're right!

SO, belay my last!

Vandit

My blowers have a slight squeak from time to time, but this morning I noticed that a fan bearing sounding squeak and my A/C was turned off and the fan was set to "0"

What could it be?