Thermo fan not turning off?

[Dano™]

Hey Guys,

Car is a 2.0L 2005 MKV TDI

My girlfriend was driving when this happened, she started the car and started to drive down the road and noticed a "strange" sound as she stopped to turn around and come back to the garage she notices a small amount of smoke come from under the bonnet so she turned off the engine immediately - the drives side thermo fan did not turn off

I came outside to have a look and noticed a slight burnt rubber smell the thermo fan seems awefully close to a rubber pipe in the engine bay and it looks like the thermo fan may not be sitting in the correct place and has rubbed on this pipe causing the smoke.

The thermo fan continued to run and flatten the battery

Has anyone had this problem at all?

Any info that would be helpful much appreciated

Cheers,
Dan

[wurlzy]

Hey Dan, not sure on VW's but I know on MINI's this same thing can happen. With them it is caused by a relay sticking on and not stopping the flow of current to the electric motor for the thermo. Have a look and see if you can see a relay box mounted either on the fan assembly somewhere or in the wiring running immediately to it, if so then give it a couple of "gentle" taps to see if that releases the relay. As I said not sure on VW though.

With the MINI's you cannot buy that relay individually, it comes complete with the thermo fan assembly!

Don't know if that will help or not, but hopefully may lead you in the right direction.

Regards, Steve.

[shakespeare]

One of the thermo fans failed on my wife's Jetta TFSI recently and was advised to replace asap as the strain placed on the other fan can be quite great and may cause that to fail too. The symptom was the fan was continually running until you switched off then it run for a minute or so. FYI cost over $600 incl labour from the VW dealer!!!

[bazzle]

Sadly sounds like a relay or module failure.
Any reason you didnt try to unlug the fan or remove neg batt terminal?

Bazzle

[barrenjoey owl]

One of the thermo fans failed on my wife's Jetta TFSI recently and was advised to replace asap as the strain placed on the other fan can be quite great and may cause that to fail too. The symptom was the fan was continually running until you switched off then it run for a minute or so. FYI cost over $600 incl labour from the VW dealer!!!

same issue for me.......going in on Friday for investigation.

[HiTorque]

Hey Guys,

Car is a 2.0L 2005 MKV TDI

My girlfriend was driving when this happened, she started the car and started to drive down the road and noticed a "strange" sound as she stopped to turn around and come back to the garage she notices a small amount of smoke come from under the bonnet so she turned off the engine immediately - the drives side thermo fan did not turn off

I came outside to have a look and noticed a slight burnt rubber smell the thermo fan seems awefully close to a rubber pipe in the engine bay and it looks like the thermo fan may not be sitting in the correct place and has rubbed on this pipe causing the smoke.

The thermo fan continued to run and flatten the battery

Has anyone had this problem at all?

Any info that would be helpful much appreciated

Cheers,
Dan

I had the small fan replaced at around $615 two years ago. It was starting every morning in 30 sec after engine was on. The tech told me that internal relay was faulty. Anyway I got "faulty" fan back and opened it and didn't find any relay - just a brashless DC motor. I connected it to 12 power supply in the lab and it started running. So I felt an "obligation" to come back to the dealer, but the a$$holes got away with this. Their point was - we fixed it! Anyway four months later it started again and finally I was able to trace it to the fault in "can bus" harness in the driver door rubber boot. I posted previously about it here on this forum. My understanding was that the small fan was controlled by temperature sensor located in low part of radiator on the driver side. I tested the sensor - it had some resistance so it wasn't connected to ground, so it must be wrong actuating signal supplied by control module that linked to "can bus", and at the same time my battery started discharging very fast. So I found damaged harness in the rubber boot, and I don't have this "fan" issue any more.

[Dano™]

Thanks for the reply's guys

I had Jmac out this morning there seems to be a few issues

For some reason the motor is too close to the front of the car or the front of the car is too close to the motor if you know what i mean!

Basically from what i can tell these are the problems:

The back of the thermo fan has rubbed against the radiator pipe through a couple of the layers of rubber - Radiator hose needs to be replaced

The belt on the side of the engine running aircon alternator etc has rubbed against a part of the high pressure side of the aircon rubbing through a hose dispelling all the gas - This hose and the belt need to be replaced.

Fan not turning off - well that cant be tested till we fix the major issues but Jimmy advised to change the temp sensor whilst everything is apart and hope that fixes the fan turning off issue - if not will need to do some further diagnostics

Bazzle to answer you question, I did not have my tools with me and the battery was flattened literally within 2min as the fan was running full tilt.

Will let you know how it goes
Hopefully not going to destroy my wallet - I wanted to bluefin it!

[Dano™]

Ended up being a broken engine mount so the motor had shifted forward causing the above damage - fans were still playing up but Jimmy did an ecu reset and the problem went away so that was lucky...

Cheers,
Dan