Overheating, fans not working

[Ade3277]

To all,

i felt I needed to share this even if the problem has occurred before and been resolved.

vehicle- 2002 Octavia vrs

problem- overheating in traffic

 

for some time I noticed that in traffic the temperature would creep up beyond the vertical, where it normally sits at 90, no matter what style of driving.

the fan would not cut in to cool.

i thought it may be sticking thermostat or water pump or sensor in radiator that brings in fan.

only on investigation and research , I discovered aircon didn't appear to be as cool as it should, therefore discovering the fan that sits alongside other also didn't work.

fearing head gasket also, I started with easiest problem, which turned out to be the problem. There are three green fuses sat on top of the battery. It was visibly clear the left one showed signs of poor contact and burning. On cleaning the contact, both cooling fan for engine and aicon fan began to work.

I hope this thread helps someone else,

cheers 

[Leeboy]

Good,  satisfying diagnosis and fix.  Always start with the simple things.   Fuses and wiring on the battery box appear to get dodgy with age on out cars.  Quite a few posts on burnt out wiring so check all connections for corrosion and damage regularly. 

 

Well done! 

[Breezy_Pete]

4 hours ago, Ade3277 said:

To all,

i felt I needed to share this even if the problem has occurred before and been resolved.

vehicle- 2002 Octavia vrs

problem- overheating in traffic

 

for some time I noticed that in traffic the temperature would creep up beyond the vertical, where it normally sits at 90, no matter what style of driving.

the fan would not cut in to cool.

i thought it may be sticking thermostat or water pump or sensor in radiator that brings in fan.

only on investigation and research , I discovered aircon didn't appear to be as cool as it should, therefore discovering the fan that sits alongside other also didn't work.

fearing head gasket also, I started with easiest problem, which turned out to be the problem. There are three green fuses sat on top of the battery. It was visibly clear the left one showed signs of poor contact and burning. On cleaning the contact, both cooling fan for engine and aicon fan began to work.

I hope this thread helps someone else,

cheers 

 

The fans themselves can fail, on the lower of the two speeds they run at. This in turn can cause a fuse to blow because when the high speed fan operation is triggered, the fans have to accelerate from stationary instead of from their low speed rotation, which needs a much bigger surge current to flow through the fuse. Once that fuse has blown, neither speed works.

 

A thread with some good discussion on low speed fan failures and links to cheap/simple remedies here: http://forums.vwvortex.com/showthread.php?4509806

 

Pretty common fault on older VAG cars, both my 2003 Polo and the missus's 2005 Fabia lost low speed operation , repaired by external resistors as described in those linked threads.

 

 

Edited 31 March, 2017 by Wino