Auxiliary Fan

[ken mohr]

You can do it with the hood open. That is the easiest. It is between 1 & 3 cylinder. I am sure it would be a lot harder from under the car.

 

[TedC]

Ken, I installed the TSF4 fan switch today. Like you said, it was a very easy job, and the part can be reached with hood open. Lost only a small amount of coolant during the swap. Ran one test with it installed. Closed at 221 degrees F, and reopened at 213. This is much better than 238. Thank you for all your help.

 

[ken mohr]

Ken, I installed the TSF4 fan switch today. Like you said, it was a very easy job, and the part can be reached with hood open. Lost only a small amount of coolant during the swap. Ran one test with it installed. Closed at 221 degrees F, and reopened at 213. This is much better than 238. Thank you for all your help.

That's about the same as mine did. Mine opened at lower temps after the initial time and I watched the other day and it closed at 215* and opened at 205*. I am more at ease with it operating at 215* than 238*.

Ken

 

[TedC]

Also replaced the pigtail connector to the aux fan switch with a Napa FSC10. The old part cracked when I squeezed it. Here are the available part numbers for this connector; BWD/Carcraft PT770, Standard S550, or Napa FSC10. Napa had the part in stock.

 

[ken mohr]

Also replaced the pigtail connector to the aux fan switch with a Napa FSC10. The old part cracked when I squeezed it. Here are the available part numbers for this connector; BWD/Carcraft PT770, Standard S550, or Napa FSC10. Napa had the part in stock.

ME TOO

 

[keremarsan]

Hi Ted and Ken Mohr !

I reply an old subject. As you did , I also replaced my 238 degree aux fan switch with the TFS4 and also the connector which was cracked.

Here is my observation : As it should , the aux fan kick on at 215 and kick off at 205 but the problem is, in these conditions the main cooling fan will never kick on ( if AUX fan is capable to decrease the temp or stop the increase of the temp )

I think there is something wrong here , trying to cool the car with aux fan... My thermostat is 185 degree ( happy to use it instead of 195 in IStanbul , hot in summer )

I really think to reinstal the 238 degree switch , please any information or opinion will be helpfull , thank you

 

[vetteoz]

Here is my observation : in these conditions the main cooling fan will never kick on ( if AUX fan is capable to decrease the temp or stop the increase of the temp )
I think there is something wrong here , trying to cool the car with aux fan..

You obviously have plenty of cooling ; my only concern would be whether the Aux fan is rated for the sort of use it is getting ; with std 238 degree switch it was only intended to run in extreme conditions.
You can wire the same switch to operate the main fan so it runs in parrallel to the ECM control.
That way the TS4 turns on the main fan at new temp but if it fails the computer will still run fan at stock temp setting

 

[adfac]

Just wanted to say "Thanks"

Here are the results of a simple stove test with the TFS4 fan switch and a 50/50 mixture of coolant.

Closed / open temp in degrees F
Test 1: 219.8 / 199.7
Test 2: 220.2 / 199.8
Test 3: 220.3 / 199.8

I was expecting results closer to 215 / 200. However, 220 is better than 238. This will allow the aux fan to kick in ahead of the primary fan which is controlled by the ECM. Unless we get a few warm days, installing this fan switch will need to wait till next year. Appreciate those who posted key input that helped us all better understand these fan switches.

TedC ... I just wanted to say thanks for this thread. I was having an overheating problem in my 86. I knew it was my aux fan and I knew the aux fan was working but just wasn't turning on when it should. I couldn't find the correct aux fan switch to replace the one that failed. I came across this thread with your detailed info, loved your idea and promptly bought a TFS4 switch. 10 minutes later I was up and running with almost an exact match to your stove tests. Thanks again. Your info saved me from alot of grief!

Mike

 

[TedC]

Excellent feedback!!! I really like this modification along with changing the thermostat to 180 degrees.

 

[adfac]

Excellent feedback!!! I really like this modification along with changing the thermostat to 180 degrees.

Yep. Main fan goes on around 175 and aux around 220 or so. Perfect setup for 100 degree summer heat! Thanks again.