[urq] radiator fan switch

laraa at sympatico.ca laraa at sympatico.ca
Thu Nov 17 07:27:57 PST 2011

That switch below the tank is dead i'm quite sure. Never saw one that still
worked and the parts from Audi that I ordered were also DOA. Now it's NLA.
It's a good idea to have that manual switch to trigger the high-speed fan

A heat gun won't get higher temps than the normal transmission operating
temperature, so no it won't be enough. If you are afraid of starting a fire,
which you won't, take the car to a shop. They will get that plug out in no
time. If it is very chewed up, welding electrically a bit of rod to have
better leverage would probably be enough to loosen the rust bond.

Good luck !


-----Message d'origine-----
De : Jim Miller [mailto:jmiller at quantumcom.com] 
Envoyé : 17 novembre 2011 10:03
À : laraa at sympatico.calaraa@sympatico.ca
Objet : Re: [urq] radiator fan switch

Thanks for taking the time to explain this in great detail for me. Years
ago, I switched my high-speed fan manually for use at the track and also
traffic. It still runs through the system and I can plug it back in at any
time to the temp switch located below the filler tank. But when recently it
wouldn't work after a long hot idle, I suspected a ground. It works when its
cold. That's why I suspect to the radiator switch.

What about a heat gun for the tranny plug? I'm a little leery having a flame
that close to fluids... not that my engine is dirty with oil leaks, it's
pretty clean.
My plug is all screwed up and chewed up from someone trying to get it out
years ago. Luckily, I have a new spare.
On Nov 16, 2011, at 6:26 PM, <laraa at sympatico.ca> <laraa at sympatico.ca>

> Hi Jim,
> Point one : 
> Yes the new switches are of the 3 pin variety and they might be more 
> robust but I don't know this for a fact. One is ground (a multimeter 
> will tell you which one via continuity with the body of the switch), 
> the next one (in the
> middle) is the 85 degree switch while the other one is the 102 degree 
> switch. Plug the two wires to the ground and the middle one and you'll 
> have the low speed fan circuit functional.
> Then, look at the hose that comes from the bottom of the coolant 
> reservoir, there will be an aluminum tube with two other wires : this 
> is the high speed switch (which is dead now I am quite sure and 
> discontinued). Remove the two wires from it, lengthen the one that is 
> not ground to reach the switch at the bottom of the radiator and plug 
> it to the remaining pin on the 3-pin switch. That way, you'll have both
circuit functional.
> Airtex is a well known aftermarket supplier. But beware that any 
> switch you buy will die shortly if your fan comes on often and for long
period of time.
> My car that sees many slow speed ice lapping events (the fan is on for 
> almost the whole 15 minutes) kill a switch at each winter... At 15$, I 
> have always a new one ready.
> Point two :
> The plug for the transmission is a 17 mm allen. Heat is needed to 
> release the galvanic corrosion between it and the housing. Buy 
> yourself a cheap
> MAPP+oxygen torch like this one (http://tinyurl.com/law6kc) and you're
> Propane only is not hot enough IMO.
> http://www.bernzomatic.com/PRODUCTS/KITS/TORCHKITS/tabid/215/ctl/Detai
> l/mid/
> 1147/xmid/6954/xmfid/3/Default.aspx
> Louis-Alain
> -----Message d'origine-----
> Hello! One quick one... or two. Looking for the right replacement part 
> for the radiator fan switch. I have discovered most of them that I 
> have come across are three pin. My old one is two. Just wondering if 
> three pin will work. If so, brand of choice and who has it. Also, 
> found a two pin but the brand name is not familiar to me. Anyone have
experience with Airtex 1S4375?
> Last, trying to get the tranny filler plug out and its way stubborn!!! 
> Any BTDT advice? Any better replacements if I get it out?
> Thanks a bunch!
> -Jim Miller
> '83 urq waiting for fresh winter coolant!

Jim Miller
Creative Director

1201 Story Avenue
Suite 123
Louisville, KY 40206

More information about the quattro mailing list