Radiator Fan Switch

does the fan come on if you jump the wires?

 

Big Dreamer,

The numbers you have are correct. I purchased the 180 degree a month or so ago and replaced it while trying to sort out the same problem that you are having. Replacing my fan switch unfortunately did not solve my problem. Last night I replaced my water temp. sender ( at the engine ) but have yet to take it out to see if that solved the problem of noted excessive temp readings while stopped in traffic. One suggestion, have a mechanic read your engine and radiator temps with an infrared gun first before you start replacing parts like I did. After replacing the thermostat, expansion tank cap, radaiator fan two pole switch, and bleeding the system I had my independent mechanic get the readings with infrared gun and it showed that the engine temp was normal and the fans were kicking on at the appropriate temperature. I cleaned the connectors of the temp sender without success which led me to replacing the unit last night. If this doesn't work my next step is to replace the bad gauge. Sorry for the long post, hope this helps. If you have any questions feel free to PM me. Good luck.

Dan

 

i have used the VW 180 switch and the Sorenson switch in 2 of my 308s so far successfully. make sure the foam around the rediator is in good condition.

 

air in the system will do just that. you may have to bleed the system several times for a week or so to get the air out. the first time you open the heater valve to use the heater usually lets air in the system also.

 

Bleeding the system of air: There are 2 locations to bleed the system of air and you should bleed from both locations. First location on my 328, and I believe your is the same, is a turn screw ( knob ) at the top of the radiator on the passenger side. Slowly unscrew the knob unil you have nothing but coolant running out. Second location again on my 328 is on the thermosat housing. There is a bolt on this housing near the center that is loosened until only coolant is running out. Be careful with the thermostat bolt. It contains a small washer and you definitely do not want to drop the small bolt/washer. Bleeding the system of air is to be done with the engine running and the heaters on. It is an easy DIY. Also be careful and wear some gloves as you would expect that coolant is extremly hot.

One question I have for you from your previous post is have you changed the expansion tank cap? I believe you stated you had steam coming from the engine bay. Changing the cap is a cheap and may solve your problems. Make sure you get at least a 14lb cap. I bought a 16lb cap made by Stant at Kragen.

Dan

 

Stant 10229 expansion tank cap is what I have on my 308GT4 - $6 for piece of mind.

 

After fighting the same issues and doing all the bleeding, etc, I finally wired a switch to the radiator fans from just under the left side of the dash. The switch is well hidden, and any time I encounter stop and go traffic or a similar situation, I just flip the switch on BEFORE things get hot. I have it so both fans come on and the temp never has a chance to get too high. It seems like preventing it initially is easier than trying to bring the temp back down once it reaches 200+. This is in Arizona where daytime ambients reach 110-115 all the time....

 

One small problem is remembering to use the switch. I had to do this with one of my Sciroccos last year after a new wireing harness was installed (long story) For some reason we could not get the fans to shut off when they were supposed to. They would come on and never shut off, so I just put a switch on them as a temp solution. I drove it that way for about 8 months and just about drove myself crazy trying to remember to turn it on. I would about 90% of the time but you won't believe how many times you WON'T think about it until a red light starts blinking. I realize a daily driver VW Scirocco and a weekend car like my 308 are very different, but not entirely.

That little thermal switch in the sensor is a much better idea for people like me.

 

I thought I would revive this for some possible helpful info. In a previous post in this thread I mentioned the countless part changes I have made to keep my water temp gauge under 220 degrees. I contacted Ricambi about a new gauge but before pulling the trigger I thought I would pull out the instrument panel and clean the contacts on the temp gauge. To my surprise that was the original problem, and no need for a new gauge. Just thought I would throw this out if anyone else runs into a similar problem and has exhausted all efforts. All is well and now I don't have to keep glancing at the temp gauge every 3 seconds.

Dan

 

How dirty did they look?

Interesting. For the past 2 decades, many the 308's (mine included) may never have been running hot after all. We just have always thought they were and so we spend countless hours bleeding and installing new thermostats and fan switches and adding watter wetter and replacing foam, etc. etc. No wonder this never solved the problem for many of us.
Thanks for the post. I may pull mine out this weekend and clean things up real well back in there.

Sometimes you just have to go back to the basics...

 

Tommy,

Sorry for the delayed response. The connectors loooked ok, no dirt or anything that stood out. It definitley was the problem. I have driven the car 3 times since cleaning the gauge contacts without any problems. I wish I would have started with this instead of going through all the other crap first. Oh well live and learn.

Dan