TFSI Overheating. Fan won't start always.

Hello,
Maybe someone can help me with my problem.

I've got a MY2009 Leon Cupra 2.0 TFSI Revo 2+..

My problem is that sometimes, only when i stay still (750 rpm) or run very slow on the first gear the car overheats. I've got a scan gauge (it reads temperature from OBD) and it reaches 95-100-105 degrees C and the cooling fan's won't start Then i start the defrost function for the windscreen and the water temps drops to normal, 84-87 degrees.
I don't have any error codes, i don't lose coolant, the oil is perfect. I also changed the G62 sensor in the side of the engine, and now i will change the G83 sensor,located on the front of the car near the radiator, on a water hose.
If i drive the car, evan if i race it, it reaches 90-92 degress but then the fan starts and temperature goes down to 81-82-83 degres.

Please help..

*Sorry for my bad english.

check antifreeze level as not enough will cause the coolant to freeze in the radiator and slow down the flow rate.

The antifreeze level is ok, i've change it twice. Is good for up to -40'C

have you checked the fuse? if fan itself starts to act up it draws more power and blows the fuse. my guess would be fan switch/radiator temp sensor.

The fuses are ok.. The fan sometimes works, sometimes it doesnt.
Witch is the fan switch? Is the G83 sensor witch is the same part (same part number) with the G62 sensor?
06A 919 501A? I have two of this sensor, one on the side of the engine, and on near the radiator on a hose.

G83 i think. the closest one to the fan and rad.

Ok, thank you very much for the informations.
Tomorrow i will change it.

Bebe said:

The antifreeze level is ok, i've change it twice. Is good for up to -40'C

Click to expand...

G12 Antifreeze can not be mixed with other antifreeze, it loses its properties.

It's not mixed with other antifreeze, only G12 +distilled water

Back again..
I've changed the G83 sensor, near the thermostat and the antifreeze and for 2 days, it went perfectly. At 91-92'C the fan started and cooled down up to 82-84'C. But today it reaches 100'C on vag com and only then the fan started..it cool down to 93 degrees, then back up to 96, at 96 the fan started again to cool and the water temp dropped. Any ideas? Still no fault code. Thank you

Problems again..
Today i changed the termostat (very hard job ) but the water temp on idling get up to 116"C on diagnostics and 110 on the instrument cluster..
I don't know what to do no more
I stoped the engine, and after that i put the key in the second position and the the fans started at full speed. (dind't start the engine, but everything else worked - when u can use all of the electrics of the car and the warning lights go on (i don't know how to say in english that in english)
I waited a few seconds and after that i started the eninge.. The water drop up to 98" and the fan stoped. After that the water begin rising temp. again..
The car have no fault codes on vag com..
I changed already the water temp sensor below the termostat, the termostat and the water temp sensor on the passenger side of the engine (uk cars).
Any other ideas?
Please help

Back with problems... The problem still persist.
No one knows what to do or what to change. I've change already the 2 sensors (G62 and g83 i think they are called) and thermostat as i mentioned above.

And also my A/C compressor died (need replacement). When it worked, i use the defrost buton and the fan started...but know with the A/C dead, it won't start the fans. (One day they started when i put the climatronic in Auto mode, even if the A/C is jamed. But no cold air at all. I read that they shouldn't start if the A/c doesn't work, but they did.)
When water reaches above 100"C i had to stop the engine to let it cool down. But when i stop it, the fans start at 85% duty cycle. When the engine is ON, even if the fan should start, they won't, they are at 8.9% duty cycle, wich is 0.
The G62 and the G83, are reading the same values.
No error code or anything.
Fan output test from VCDS (vagcom) works fine, reving the fans from 0 to full duty cycle.

I also attach 2 pictures, the first with the engine on, and the second after stoping it.
on:
off:


And 2 youtube videos with some temp logs:
http://www.youtube.com/watch?v=i1oiQWHTEk8
http://www.youtube.com/watch?v=gOCfAXSlCbA&feature=related

And one thing, i think it's important..
I start the car and let it idle for 20 min, the first times the water reaches 87-92, the fan will work just fine. It works a few times, 3-4-5 cycles the fans work good and then, they won't start anymore, and the water just keep rising. I did not move the car or anything, i just let it idle. Do you think that it would be possible to be broken the fan modul control, the one incoporate in the big fan? Or something else? It's oblivious that something won't work after the engine heats up a few times..

Thank you very much and excuse my bad english.

Thank you for the answer.
The mechanics say that the water pump is ok, the radiator is hot both left and right..

I mention again, the cooling works fine a couple of times, 30 minutes i say...and then, it stops working..

Hello... i still have this problem..
Since last post i've changed: the water pump and the big fan. The problem is getting worse, everyday i use the car, after a time, it overheats at idle or runing in 1st gear.. Help?

Bebe said:

Hello... i still have this problem..
Since last post i've changed: the water pump and the big fan. The problem is getting worse, everyday i use the car, after a time, it overheats at idle or runing in 1st gear.. Help?

Click to expand...

Is your AC back up and running mate?


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If i drive with the AC ON everything is ok. It happens when the climatronic is shut off or on ECON mode.

Have you replaced the fan control module?
From my understanding there are two control circuits for the fans, controlled. Y this module. One for when the AC is on and the other for cooling.
The fact that you've replaced every heating sensor and theism fan, and that your fans still operate when AC is on would make me think that the control module has failed.

I think the little fan only runs once the big fan is operating/at full speed.

Have a search on line as I think it has been a fairly common failure on other VAG cars.

Cheers


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