Rad fans!

vworks

Veteran Member
Joined
Jun 13, 2000
Location
Hudson, Quebec, Canada
Now that the warmth is pushing back the cold it is getting that time once again to start using our air conditioning. I noticed the other day that both of my radiator fans are on all the time when the AC is on. I then put my video camera under the hood for my drive in to work. The fans are ALWAYS on-even on the highway. Someone please tell that the boys(and girls) at VW did not do this on purpose. Even the crapcan domestic cars turn the fans off at a set speed. My two rad fans could never pull the amount of air that goes through there at highway speeds. My old Maxima would turn off the fans at any speed above 50kph. That makes much more sense to me. Could we wire in a relay with the VSS(vehicle speed sens) to disable the fans at a set speed?
 

vworks

Veteran Member
Joined
Jun 13, 2000
Location
Hudson, Quebec, Canada
When I turn off the AC the fans slow down to about 100rpm. They always seem to freewheel at that speed no matter how fast I'm going. If I hit the AC they spin up to their usual speed(like parked with the AC on) These electric motors will only last so long. I would still like to rig up something to turn the power off at a set speed. Any ideas would be great.
 

vworks

Veteran Member
Joined
Jun 13, 2000
Location
Hudson, Quebec, Canada
Blaupunkt, trust me when I say that your rad fan DOES come on when you put your AC on. If you had no airflow through your condensor(such as at red light) the pressure in the system goes up fast-like 10psi per secomd. I've seen it with the guages attached to the system. There is now way that an AC sustem on a car would last more than 10 or 20 seconds without airflow. A mechanic of mine put a new condensor on a MK111 Jetta. After he was finished he put the car outside to pressure wash the engine bay. He forgot to plug in the rad fan when he was finished. After about thirty seconds of idling with the AC on the pressure relief valve blew-R134a up in smoke. The VW's have a valve made out of very thin alluminum(0.010 thick) that is mounted to the reciever/dryer. once it blows you have to buy a complete ney unit(to the tune of $400.00)The whole principal operation of air conditioning relies on cooling off the condensor. I know that all of the newer VW's with air have a three speed fan on the rad. When I switch on my AC the very lowest speed comes on. I've never heard the fans come on more than the slowest speed-even in heavy traffic(stop and go) Mabye you just never here the fan come on.
 

Steve

Veteran Member
Joined
Oct 19, 1999
Location
Canada
TDI
2009 Sportwagon TDI
Are you sure the fans are just free-wheeling in the wind?

I don't think I've ever heard my fans start-up. Whenever I've looked while the engine was running, the fans were not running.

I dunno if I've ever checked the fans while the A/C is on.

[ April 16, 2001: Message edited by: Steve ]
 

vworks

Veteran Member
Joined
Jun 13, 2000
Location
Hudson, Quebec, Canada
Guess the are no VW owners that care that their fans are spinning ALL THE TIME when the A/C is on-even at 80mph. My sister just replaced her rad fan(brushes finished) to the tune of $400.00! What a crime! I thought VW's were better cars.
 

vworks

Veteran Member
Joined
Jun 13, 2000
Location
Hudson, Quebec, Canada
Karl. it's npt like it was raining outside. It just burns my ass that the fans are on whenever the A/C is on. There is not one good reason that they should be on while driving on the highway.
 
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