Stupid Question of the day: Cooling fan Cycle.

[refugeefromcalif]

I was wondering if anybody else has had the same thing happen with the radiator fans in their car.

In the past week, I've turned the car off 4 times just as the cooling/radiator fans have turned on. The next time I started the car, the fans start running immediately, then shut off after about a minute?
The outside temperature conditions between shutting the car off and starting it again, have varied by as much as 40 degrees. From warm down to Cold. (60 down to 30 degrees).

I'm not worried about this but, Just curious why a 30+ year old car would Remember what fan cycle it was on when it was shut off?
I've never had any vehicle do this before.

George

[Cory W]

If the car was still warm/hot, the coolant near the otterstat would still be hot enough to keep it open, running the fans. Once cooler coolant starts passing by it, the otterstat will close, turning the fans off.

EDIT: Just noticed the outside temperature changes between starting. If it's an overight or beginning/end of day thing, is the otterstat sticking? Could be a sign it's on its way out.

[refugeefromcalif]

EDIT: Just noticed the outside temperature changes between starting. If it's an overight or beginning/end of day thing, is the otterstat sticking? Could be a sign it's on its way out.

It's been up to 2 days between shutting the car off and re-starting it. Same thing has happened.

George

[Bitsyncmaster]

Do you have a stock setup or someones fan controller? As long as your AC is off, the only thing in the fan circuit is the relay and otterstat.

[Cory W]

I had bad luck with otterstats the first few years of ownership. Went through one just about every season. It's why I dwell on it.

Quick and easy test to at least count it out: Unplug the otterstat. You only need to unplug one of the two plugs. If the fans still run, it's something else.

Based on the outside temperatures, is it fair to assume you aren't running the A/C? Fans run while the compressor cycles.

[DeLorean03]

Do you have a stock setup or someones fan controller...?

+1. The FanFail 2x2 did this back in 2005 and 2009. Replaced it with a Joe Cool unit - been great ever since.

[refugeefromcalif]

Do you have a stock setup or someones fan controller? As long as your AC is off, the only thing in the fan circuit is the relay and otterstat.

Nope, I've got the stock setup.


Based on the outside temperatures, is it fair to assume you aren't running the A/C? Fans run while the compressor cycles.

Nope, no A/C running.

Thanks for the suggestions on things to check guys.

It doesn't concern me because it runs for less then a minute when I start the car the next time and, Only if it was running when I shut the car off.
I was just curious if anybody else had their car do this.

George

[Ron]

Nope, I've got the stock setup.
In that case, I would suggest you do as mentioned earlier and disconnect either wire going to the Otterstat and if the fans shut off, replace it before it bites you...

[David T]

At the very least get one and keep it in the car (with a seal and a zip-tie) just in case. From the description of the symptom I would just go ahead and replace it after confirming the fans and the wiring are OK by taking the wires off the switch and the fans stop and when you touch them together they run. I had one bad switch that had a crack in it and it was shorting to ground. Caused the fans to act weird but it worked fine by jumping the switch so I knew it was bad and when I removed it I saw the large crack in it's side.
David Teitelbaum