# My 1994 Audi 100 Quattro is overheating



## deengo (Sep 4, 2004)

Since I bought the 1994 Audi 100 Quatro in April 1995, I have not had any troubles. It currently has 336,552 Kilometers [about 209,123 miles] and still going strong. Other than the regular scheduled maintenance outlined by Audi, I haven't had any concerns.....until now.
I find that the radiator fans do not come on unles I turn on the A/C. If I don't turn on the A/C, the coolant boils over and sips out through the spil-over hose. The coolant empties out as a result of this after about 2 hours. I have since stopped driving it as I don't want to cause any more damage.
Are there any suggestions or recommendations? I don't trust the garages [even the dealers service techs], especially when they see/know that the owner isn't too techy about cars...just loves to drive them. 
Any suggestions/recommendations will be welcome.


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## gidrew (Mar 28, 2004)

*Re: My 1994 Audi 100 Quattro is overheating (deengo)*

well it sounds like 1 of 2 of your temp senders is bad. never worked on the V6's or there aux. pieces but slide under your car and look at the bottom of the radiator, there should be something screwed into the radiator with an electrical hook up running out of it. That controls your fan speed. 
The other temp sender should be right next to the block, on the 5 bangers it is just below the large hose that runs from the top of the radiator to the side of the block into a little housing that is bolted to the side of the block, thats what it's screwed into. 
I could replace those, you can pick them up on ebay pretty cheap, that should do the trick.

Does your temp gauge in your cluster work??


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## deengo (Sep 4, 2004)

*Re: My 1994 Audi 100 Quattro is overheating (gidrew)*

Thanks a lot for the information. I shall look up the parts on e-bay. Do I need to change both Temp Senders or just the one next to the block? I looked up ebay, all searches for 'Temp Sender' returned null.


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## deengo (Sep 4, 2004)

*Re: My 1994 Audi 100 Quattro is overheating (deengo)*

I managed to search for 'temp Senders' on ebay but it displayed all but for Audi. Are there any other sources


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## aliensyncro (Mar 26, 2002)

*Re: My 1994 Audi 100 Quattro is overheating (deengo)*

http://oem.thepartsbin.com/par...witch
theres the link to the fan switch that is in the radiator. tried doing a search for the coolant temp sensor and was unable to find it tho i highly doubt the coolant temp sensor would cause your fans to be inop. i would look at the wiring from the fans and trace them as far back as i could. i almost guarantee theres broken or corroded wiring at the fan relay or the radiator fan switch is bad.
my $.02
good luck!
chris fryer


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## alex97jazzblue (Oct 17, 2001)

*Re: My 1994 Audi 100 Quattro is overheating (deengo)*

I would peep out your thermostat as well. That is see if it is sticking or the wiring has gone bad. My audi 5000tq was recently running really hot and i replaced the thermostat and hit the terminal ends with a wire brush.


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## deengo (Sep 4, 2004)

*Re: My 1994 Audi 100 Quattro is overheating (aliensyncro)*

Thanks a lot guys for your help.......It was the Rad Fan temp switch and I had that changed. I had to change the coolant reservoir as well because of a crack.......Now my baby is back on the road and fine.
I guess it needed a bit of TLC and attention....
Cheers everyone


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