N_Halbert

Well the other day I came home and the parked the the car. An hour later the fans were still running. So, I added an additional external fan to be sure it wasn't a case of the block cooling down slowly. NADA.

After going through cooling system test at Clarks-garage, it appears that it is the Thermo Temp Switch in the radiator. Unplug it, fans stop. Jumper 2 & 3 fans run with ignition off.

None of the local parts stores carry it and short of going to Porsche or Mail order, is there a VW or Audi match for this? I have both dealers local.

Yabo

I believe you can get it from FCPGroton at foreigncarparts.com i believe, in groton, CT. Unsure if there is a compatable. Advance auto parts claimss they have it but I ordered it and it wasn't the right part.

FCPGroton will be only a day-2 to ship to you, depending on where in mass you are you could probably drive there in an hour or so if you wanted to (down 395)

UncleMaz

Your local auto parts store can almost assuredly get you one. I picked one up at Kragen's with a one day turnaround. Make sure you bring in the internet price and you have a choice between low temp and OE style.

Randy_J

I just replaced that thermal fan switch - very easy for N/A cars - I bought the OEM part for under $20 with taxes from a Porsche indie shop. Took me at most 45 minutes to do the swap - if you don't mind losing 2L of coolant, you don't even have to drain the rad. I run Water Wetter anyway, so no glycol went down the drain.

here's my recent post
https://rennlist.com/forums/924-931-944-951-968-forum/366762-thermo-fan-switch-replace-from-the-top.html

DarylJ

The thermo switch is not your problem. Check the resistance on the switch. The one I just replaced was bad, and 2&3 were always shorted. Which means every time the ignition was on the fans were on high. But when the ignition was off, they fans were off. When I was testing the system per Clark's jumpering pins on the plug, no fans ran with the ignition off. They only ran when I switched it on.

I maybe be wrong/car broken/whatever, but I really don't thing the termo switch is it in this case based on what you said. Check the resistances on the switch itself first.

Just hoping to save you some trouble.

N_Halbert

I ended up ordering one through the local NAPA.

According to Clarks when the swtich is off, jumpering 2 and 3 should run the fans. If not then the issue may be with the relays. This is on an S2. The full run down is. (from memory)

igniton off
car cool
Thermo plugged in
fans run slow

igniton off
car cool
Thermo unplugged
fans stop

igniton off or on
car cool
jumper 2 and 3
fans run slow

igniton off
car cool
jumper 1 and 3
fans do no run

igniton on
car cool
jumper 1 and 3
fans run fast

So it it appears that the relay is working correctly. One interesting thing I found was that if you pull one of the fuses for the fans while it is running the decreasd load is detected by the relay and the other fan is kicked into high.

Now changing this bugger will be fun. On the S2 it under the air intake/maf and top radiator hose. Not to mention needing little hands.

N_Halbert

In case your interested. The location of the Thermo Fan Switch.



I started by reading the instructions at Clarks Garage Thermofan Switch Replacement
I did find that it is not necessary to drain the radiator to replace.
Jack up the front of the the car and remove the bat wing.
I placed a large box lined with a trash bag as a catch basin.
Loosen up the switch up to the point is about to fall out.
Take the new switch in hand.
Spin the old switch out and let it fall.
Quickly insert the new switch and tighten it down.

Using this method I only lost 1 to 2 cups of fluid and there was no mess to cleanup.

bearone

it's also a vw part.

87951

N_Halbert

Thanks. That is what I was wondering. I tried to do a search at some of the VW parts sites but didn't come up with anything that looked like a match.

I had thought someone had been maintaining a make cross reference for such things.

bearone

rabbitt

87951

WizPorsche944

Should u still bleed it afterwards ?