Fans not stopping

[john 05141]

With a tested working otterstat, the fans kick in as normal.

However after having cooled down enough, the fans keep going until shutting down the engine.
Otterstat new, fan relay also new, no change.
Previously, the car had a bypass to manually engage the fans. The previous owner did clean up the elctrical wires, but this problem was there before.

All relays are renewed.
It has the new generations fans for a few years, so long before this problem occured.

Anyone had this experience
Is new wirering the only solution?

Help and suggestions much appreciated!

John

[David T]

Next time this happens, disconnect the "O" switch and see if the fans stop. Only 2 things are supposed to run the fans, the "O" switch and the A/C compressor clutch. If the A/C is off it has to be the "O" switch unless there have been wiring modifications or a problem with a relay. Could also be a bad diode allowing a backfeed to hold the relay. For testing purposes unplug the diode next if the fans don't stop by disconnecting the "O" switch.

[Helirich]

How are you determining the water temp is cool enough to shut them off. I hope your not relying on the dash gauge.

[ssdelorean]

This happened to me whenever I installed a "new" otterstat. The only thing that would fix it was to put in an original otterstat. None of the new ones would turn the fans off on my car for what ever reason. Still don't know to this day. I keep an original as a backup incase my original decides to fail.

So I would guess as a test, put your original back in and see if that works. If so, your car is a weird one just like mine :-)

[MrChocky]

This happened to me whenever I installed a "new" otterstat. The only thing that would fix it was to put in an original otterstat. None of the new ones would turn the fans off on my car for what ever reason. Still don't know to this day. I keep an original as a backup incase my original decides to fail.

So I would guess as a test, put your original back in and see if that works. If so, your car is a weird one just like mine :-)

Hell, keep any spare parts unless they are toast. It appears that the seal on my project's otterstat is poor, but as it happened when I fitted in other car, I didn't fit the seal, so I have a brand one one to fit - that is, as soon as I turn it the correct way around - it's mounted upside down.

[Helirich]

This happened to me whenever I installed a "new" otterstat. The only thing that would fix it was to put in an original otterstat. None of the new ones would turn the fans off on my car for what ever reason. Still don't know to this day. I keep an original as a backup incase my original decides to fail.

So I would guess as a test, put your original back in and see if that works. If so, your car is a weird one just like mine :-)

When you say "original", what do you mean? Is that like NOS? Are the new otterstats of a differnt design?

On my project truck I got two temp switches. They came from the bay. They have em that turn on at all differnt temps. I have one turn on at 190 and the other at 200. (There's two fans and one can keep it cool most times) They are nice quality, but they thread into 1/4" pipe. I may weld a bung on my tube for one if mine gives me trouble. I will say I like pipe threads better than clips and tyeraps.

Ssdelorean, if you don't mind, could you tell me how many times you had to replace your axle boots?