Hi everyone,... just had my air-con re-gassed, as I don,t like it standing around for longish periods without a full charge, ie lubrication of the system etc.
Question is I asked the guy about downtime and that I like to run the air-con for about 5 mins,... and he said,.. no need to do that ,.. all you have to do is turn the front pulley on the compressor an that will do the same.
Q,.. does that make sense?

Regards
Ken

 

Not an expert, but used to live in Northern Minnesta where we'd let our cars sit for months on end. Once a month we'd start the cars and let them run for a while. Get it up to operating temp and run the AC full blast for a while. I've heard the seals will dry up if not used. Turning the front pulley doesn't seem like it would do much. I'm sure someone with more experience will chime in...

 

I'm from the school of chicken soup as a remedy: Does it help? "Couldn't hoit"

There's no downside to cranking it up every few weeks, so I say go for it just to be safe.

 

I lost my a/c when the control module blew out. Although fairly new to 928's at the time, I still wasn't prepared to pay the price of a new one to the dealer. Especially as the local climate doesn't really warrant a/c for more than a few weeks a year. Six or seven years later, I found a near new control unit at a bargain price, so I bought it, even though I figured surely the seals were long dried out and the system would be empty. Turned the a/c on and to my great surprise it was blowing very cold air!
My understanding now is that when the hvac is set to the "defrost" setting, the a/c is engaged. Since I drive my car all year round and use the defrost heavily Oct.- April that must have kept the seals in good condition, even though I never used the a/c all those years.
Glenn

 

Many thank,s for the input guys,.. I guess i,ll just stick to what iv,e been doing for the past 16 winters,.. ie run her up to speed and run the air-con for 5 minutes,..... seemed to me a little far fetched to expect all "O" rings etc to be lubed by just turning the front compressor wheel by hand,...... trouble is this guy has been in the air-con business all his life,.... and I thought,.. well he must know something about cold air.

Once again guys I appreciate your thoughts
Ken

 

The o-rings don't need the oil refreshed on them, but the mechanical seal in the front of the compressor does. The rotating part of the seal has a graphite face on it, with a stationary ceramic face that it rides on. The actual sealing depends on having a thin film of oil between the two faces. When the car sits, the oil film in between the faces may develop a track that allows gas to escape. Rotate the clutch just a bit and any tracks through the film are wiped over and the sealing integrity is restored. Bottom line-- no need to run the motor just for the AC system, when a hand turn of maybe a revolution is all you need. Be sure youi are rotating the middle section of the clutch hub.

 

I have never rotated the clutch inside the pully. Is it so easily rotated that finger pressure will move it, or how do you get a hold of it to rotate it?

 

Very interesting Bob,.. so it does make some sense, thank,s,..... as regards the centre pulley on the compressor Charley,.. it turns quite easily by hand with little effort.
Kind regards everyone
KEN

1980 928s 300bhp 5speed
1994 Mitsubishi Pajero (Montero, States)

 

you should be able to do it by hand...

 

So that takes care of the AC compressor O-ring. Isn't it better for the rest of the engine to let it run for a little while so none of the other parts dry out?

Also, you're putting a fresh coat of oil on the entire inside of the engine where it might have drained down.

I know this thread is about the AC, but for anyone storing it over the winter, is there a downside to starting it up every few weeks?

 

I think the plus points outway the minuses,... every 3 to 4 weeks during downtime iv,e run mine up to temperature (moderately) and made sure that the engine is hot enough to dispel any moisture that would remain in the exhaust system, also I move the car up and down my driveway to ensure no stickiness in the brakes and clutch and generally stir the cogs,... try all the electrics, windows, lights, sunroof, all the usual culprits that cause those annoying electrical gliches, plus iv,e always switched the air-con on for 5 minutes,.. and give the battery a trickle charge once a month for about 3to4 hours,....of course I,d really like to drive it yearly,.. however around where I live in England at the first sign of a frost they put tons of rock salt on the roads, and i,m sure anyone that knows is very bad,... particularly for my 80 MY 928.
Regards everyone
Ken