Small cooling fan failure report

[HiTorque]

This potentially can happen to anyone with $600+ impact on your wallet. The design for engine overheat protection seems to be OK, but some questions remain.. The little fan has built in thermostat- temperature sensor that closes its contacts when engine temperature is above some threshold. This could mostly happen when car is stationary with running engine. The distance between the sensor and front part of the engine is around 50mm. When car is running the air will cool down the engine and sensor, so it kicks in in most likely in "stationary mode". So my sensor was kicking in within 1 minute after engine started and fan was running nearly all the time. So the heat will eventually damage the sensor and you have the option of leaving it as is or fork out $600. I got my faulty fan back and so far could not find easy way to open it up, made by Siemens btw.

[Maverick]

This potentially can happen to anyone with $600+ impact on your wallet. The design for engine overheat protection seems to be OK, but some questions remain.. The little fan has built in thermostat- temperature sensor that closes its contacts when engine temperature is above some threshold. This could mostly happen when car is stationary with running engine. The distance between the sensor and front part of the engine is around 50mm. When car is running the air will cool down the engine and sensor, so it kicks in in most likely in "stationary mode". So my sensor was kicking in within 1 minute after engine started and fan was running nearly all the time. So the heat will eventually damage the sensor and you have the option of leaving it as is or fork out $600. I got my faulty fan back and so far could not find easy way to open it up, made by Siemens btw.

You could have added an external trigger for the fan so when it hits x degrees it turns on and off once it drops past y degrees. Would have cost around $50 for the parts. But if you have to pay someone to do the work it probably wouldn't save you much.

This shows the value in getting the extended factory warranty at ~$1200-1400 as you're covered for anything like this! Cheap insurance IMO.

[HiTorque]

The little fan has built in thermostat- temperature sensor that closes its contacts when engine temperature is above some threshold. This could mostly happen when car is stationary with running engine. The distance between the sensor and front part of the engine is around 50mm. When car is running the air will cool down the engine and sensor, so it kicks in in most likely in "stationary mode". So my sensor was kicking in within 1 minute after engine started and fan was running nearly all the time. So the heat will eventually damage the sensor and you have the option of leaving it as is or fork out $600. I got my faulty fan back and so far could not find easy way to open it up, made by Siemens btw.

I opened the fan and found that there is no thermostat or any sensor inside. The DC motor is in perfect shape, no burning marks, brushes are OK. So I went to the service dep-nt and started asking the questions, but now they were saying that sensor was in the big fan, and it's not a sensor, but speed controller, and the most important the car was fixed. I still didn't get any explanation why they replaced perfectly running fan. So I need an expert advice as I feel being ripped off.

[gregozedobe]

I'm slightly confused. Did they replace something else as well as the little fan ? ie the speed controller in the big fan, and this was the actual problem and has fixed everything ?

If so, and the little fan was perfectly OK but they replaced it as well, then yes, you have paid to replace something that didn't need replacing due to their (charitable interpretation here ;) ) inadequate diagnostic process.

[HiTorque]

I'm slightly confused. Did they replace something else as well as the little fan ? ie the speed controller in the big fan, and this was the actual problem and has fixed everything ?

If so, and the little fan was perfectly OK but they replaced it as well, then yes, you have paid to replace something that didn't need replacing due to their (charitable interpretation here ;) ) inadequate diagnostic process.

Nop, the only thing was replaced - the small fan.

[gregozedobe]

Nop, the only thing was replaced - the small fan.

I'm still a bit confused.

If the ONLY thing they did they did was fit a new fan (ie no work was done on any sensors and/or controllers) and the new fan DID fix the problem, then it sounds like they have done the right thing (and there must be something wrong with the small fan, despite all appearances to the contrary).

[HiTorque]

I'm still a bit confused.

If the ONLY thing they did they did was fit a new fan (ie no work was done on any sensors and/or controllers) and the new fan DID fix the problem, then it sounds like they have done the right thing (and there must be something wrong with the small fan, despite all appearances to the contrary).

I am saying that there was nothing wrong with old one, I put it back last weekend and no dramas works Ok. It was like going to dentist to fix the filing and he would instead take another tooth out and bill you for filing and for the extraction. You can argue but tooth is no longer there...

[gregozedobe]

Maybe there is an intermittent fault (somewhere) ? You did say the problem is no longer occurring. I hate intermittent faults, they are a real PITA to properly track down and fix.