Alfa 166 Cooling fans stay on constantly, realy problem?? - Alfa Romeo Forum
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Alfa 166

Help Alfa 166 Cooling fans stay on constantly, realy problem??


I have an Alfa 166 2.4JDT with in the front two cooling fans. Both fans keep on working, even when the engine is off for a couple of hours.
Even my battery was empty the next day, so I disconnected the cables from the cool fans. But this must be repaired asap.

Does anyone know if this is a fuse/relay problem and where can I find the relay(s) for the cooling fans?? Comments are welcome!

Thank you veru much!!
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Re: Alfa 166 Cooling fans stay on constantly, realy problem??

Th eproblem with the fan being permanently on is two fold - first the engine will only ever reach the min temp at which the thermostat opens, & take longer to warm up, secondly the fans will consume power which you'll pay for in mpg

My 164 had similar symptoms - once the engine got hot enough to switch the fan on, they stayed on permanently. Sometimes even when the engine was started from cold afterwards

The cause for me is the radiator fan temp sensor.

A check would be to disconnect the sensor when the fan is misbehaving - if it goes off, its the sensor.
On the 164 the connector is easy to see on the top back edge of the rad - dunno on the 166

Easy enough to change on the 164 - it's just screwed in to the rad - again dunno on the 166.

My present bodge is a manual switch, run into the cabin. changed the sensor about 6 months ago, so I'm suspecting something has caused the sensor to fail. Works well enough, if you remember to watch the temp.

Does anyone know whether these sensors are vulnerable to voltage/current/over temp/vibration??

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Re: Alfa 166 Cooling fans stay on constantly, realy problem??

Was a relay with the 164, one of three left front of the grill. It drained the battery completely the first time it happened, and I needed a monster jump from the AA just to get going. Disconnecting the fan will allow you to save the battery enough to restart, and a bit of sandpaper will likely fix the relay.
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Re: Alfa 166 Cooling fans stay on constantly, realy problem??

the radiator needs to be changed in the 166, its a common fault. You may wanna give that a check
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Re: Alfa 166 Cooling fans stay on constantly, realy problem??

I've started to get the same problem myself.

I've got a 166 3.0 (1999). It's happend twice now. 90% of the time it's ok but last night it drained the battery.

So I disconnected the fan while it sat in the driveway. When I reconnected a few hours later the fan stayed off. Took it for a run, the fans kicked in as usual. Shut the car off, the fans stayed on for about 10 seconds then went off. - as they should...

But what is causing this intermittent fault ? I had a brand new radiator installed a few months back....... or is it the sensor on the rad at fault?? I reused this when I put the new radiator in......


Alfa 166 3.0 Sportronic
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Re: Alfa 166 Cooling fans stay on constantly, realy problem??

i'd put money on the temp sensor for the fans failing....prob seperate to the one for the temp gauge so wouldn't show up as a fault there....
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