Just today my cooling fans started to run upon starting the car and continues the whole trip. Does this mean my thermostat is stuck open? Can I drive it this way at least for awhile with no damage of any kind? Thanks.
Location: Fort Mill, SC
Posts: 235
My VIN: 16882.
Just today my cooling fans started to run upon starting the car and continues the whole trip. Does this mean my thermostat is stuck open? Can I drive it this way at least for awhile with no damage of any kind? Thanks.
Location: Belluno, Italy
Posts: 628
My VIN: 3305
I had this issue last weeks, for short trips I used to disconnect the wires at the otterstat, but I had a coolant leak there so I guess that the water made the current keep on flowing regardless of the temperature.
Replacing otterstat and seal solved the problem, but this may not be your case!
Posts: 4,808
My VIN: 3937
It probably means that, but some more troubleshooting can (somewhat easily) narrow it down for you.
If the otterstat is the problem and is stuck in a position to tell your fans to stay on, you can test it easily by pulling off the wires on it. Driver's side of engine, coolant pipe lower, near exhaust manifold. Disconnect the electrical and see what happens. You don't need the engine running for this either coincidentally, so you can test in a number of different ways. If they shut off as soon as the wires are disconnected, then this is likely the problem. If they stay on, it's something else.
If they stay on, you could also have a short to ground from the positive wire which effectively tells the fans to turn on too. Or it could be in the other half of the equation which turns your fans on, that being the A/C system.
Try the otterstat test first and report back. Also have a look in your fuse and relay area to see if anything looks melted. Report back what you find.
If the problem was solely your otterstat stuck telling the fans to turn on and nothing else, you can drive like this for now. It's not terribly efficient as you're sending a lot of power to the fans and your fuel mileage will suffer. You might also see more problems if the cause is electrical as you'll be forcing the car to stay in an electrically demanding mode and something else could get melty or problematic.
EDIT: if it is sticking on, it could be an air pocket telling the car the coolant is too hot. Again, easy test while the engine is off and preferably cold as even if it is an air pocket, it shouldn't tell the fans to come on if cold. If it's cold and the fans come on this way, it likely means it's shorted internally for some reason.
Last edited by Jonathan; 10-15-2014 at 01:38 PM.
Location: Fort Mill, SC
Posts: 235
My VIN: 16882.
Can someone post a picture of the otterstat? I have no idea what it looks like. Thanks.
Location: Fort Mill, SC
Posts: 235
My VIN: 16882.
By the way, the fans come on as soon as I turn the key; the car doesn't have to be running. As soon as I switch the key off, the fans shut down, one after the other, within 5 seconds. I have checked the fuse - no problem there.
Location: UK
Posts: 207
My VIN: 4494
Club(s):
What is your AC Set to? Max AC and fans set to 4 puts the cooling fans on, if I remember correctly?
Location: Fort Mill, SC
Posts: 235
My VIN: 16882.
AC is off. Just an update - I found the otterstat, and upon disconnecting the wires, the fans turn off. (cold engine.) Connect the wires, with key on, fans come back on.Originally Posted by jwrayth
Location: North GA
Posts: 6,177
Club(s): (SEDOC) (DCUK)
Time for an otterstat then.
Posts: 1,313
My VIN: 03238 Grey & Black Hybrid - Auto - work in progress Former owner 10902 - Universal 93 Raffle Car
Any time the AC compressor clutch pulls in the fans come on.
With the engine running but not yet warmed up and the AC off open the engine cover - the AC compressor is the belt driven device near the top of the engine on your left side as you look at the engine. The belt and pulley are obviously turning all the time, but there is a clutch that engages the compressor - if the end of the pulley is spinning, then the clutch is engaged and the compressor is pumping - the fans will/should always be on when this happens - if it is not pulled in then thats what you would expect in this mode. Now go turn the AC on and watch the compressor for at least 30 seconds, if the clutch engages and the end of the pulley spins, the fans should turn on with the compressor and turn off when it shuts off.
Knowing what is happening with the AC compressor will help with the diagnostics.
Look at the first diagram here:
http://dmctalk.org/showthread.php?40...ing-Schematics
You will find a brown orange wire that says to otterstadt that goes to a relay - that is the trigger on the relay that turns on the fan. Now notice that the pink wire from the compressor splices into this wire, so that either the compressor or the otterstat can trigger that relay and run the fans. The triangle and line at the splice point are a diode - like a one way gate. This allows the electricity to tun through the pink wire into the brown orange wire to trigger the relay, but it prevents electricity from going the other way down the ponk wire and turning on the compresser whenever the otterstadt is hot.
The otterstadt is in the silver water pipe a bit below the ac compressor. the water pipe should be installed so that the otterstadt is in the underside of the pipe, so you have to run your hand along its length until you find a sensor plugged into the pipe with two wires in it. That sensor is the otterstadt - it is a temperature switch that closes the circuit when it gets hot, so electricity can glow through it and out the brown orange wire to the relay that turns on the fans. By the way - its worth pointing out that you MUST install a cable tie around the water pipe to help hold the otterstadt in position, or it can fall/shoot out and you will destroy your engine with no warning in just a few minutes. there are other threads on the forum with diagrams if you don't have the cable tie. See posts 32 and 43 in this thread for info on how and why to cable tie your new otterstadt in place...
http://dmctalk.org/showthread.php?84...ed-Today/page4
So - the otterstat can fail such that the fans are always on, or never on. The switch is fragile - if you replace it don't drop the new one. Its easy to check its operation with a meter or a test light. If there is continuity between the two poles when the engine is hot, but now when its cool, hen its generally working properly - any other conditions and it has failed. If the problem is your otterstadt then it has failed such that the circuit is complete even when the engine is cold. Again, easy to determine, with the engine cold and the fans running for no good reason, unhook one wire from the otterstat and the fans should stop.
If the fans keep running, and your AC is off with pulley not turning, then the problem is in the fan relay or fan controller.
Test your otterstadt and see what your AC is doing to see if you can narrow the problem and come back and we can work it out.
BTW - there is no big problem running with the fans stuck on - its just harder on the electrical system but that is not an acute issue - if your fans are stuck off you can get in big trouble fast.
T
Tom
Last edited by TTait; 10-15-2014 at 05:26 PM.
Posts: 4,808
My VIN: 3937
I saw your post after this one mentioning the otterstat wires pulled gets them to shut off. That's good.
This mention here though about one after another and within 5 seconds has me wondering if you have any non-stock fan controller installed in your car? I don't have one myself, and don't know for certain how they work, but the factory set-up didn't stagger them one after the other as far as I know. Perhaps if you have a Joe Cool or Dave (bitsync)'s fan controller they could chime in on whether it might be having a problem too? It might just be the otterstat is shot, but it could be more than that too.
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