Fans not cutting in on V280

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New Member
Jan 10, 2006
HI there

We have a V280 people carrier around 6 years olds.

We've had a problem where the car is overheating from time to time. We've had it in to a Merc main garage who told us the air con compressor had failed. As our warranty wouldn't cover their labour charges, we took it to an aircon speciallist, who told us the air con compressor was fine, and the air con was coming on soon as you turn the ignition on. They found some wires to the fans which the insulation had been stripped off, and thought this may be causing the problem. They replaced the wiring, let the car idle for some time, had no sign of overheating and sent the car back to us. All seemed fine and haven't had any problems for the 10 days since.

Have just had it serviced by a local garage, who have found that the temp had got somewhere between 100 and 120 and no fans cutting in.

Anyone got any ideas what the problem might be (keep the answer's simple as I'm a woman and don't really understand cars very well!!!)

Any help much appreciated!
have you noticed the overheating whilst stuck in traffic and than the temperature falls once you're on the move again? If this is the case than It may be the Thermostat. This is fairly cheap and easy to replace.

If the above is not the case than it could be the fan coupling, which sits behind the fan. This can be fiddly and you would need to get your mechanic to change this.

I don't have any other suggestions, but maybe some one else on this forum, might.
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This is exactly what is happening. First occaision was when i was stuck in traffic for about 30mins for a 500m journey, when it overheated and the coolant overflowed.

Other times have been when the car has just been idling, but doesn't seem to happen everytime.

Many thanks for your prompt response
Viscous Fan Coupling

This happened on my SL... I took it to my local MB specialists and they found the the Viscous Fan Coupling was knackered... they replaced and the problem was solved.. the job cost arount £250 inc parts, labour and VAT
Basmar - I notice you are in London - which MB specialist did you use, and can I ask roughly how long ago you had this problem (gives me a chance to gage price increases!!!)

AMC - Earlsfield

I use AMC in SW London
They are Merc and BMW specialists... The repair was carried out 2 weeks ago :)
ill echo the relay fix.. intermittant fault = electrical if you ask me. If it happened every time, id say the fan.

Just to check - with the air con OFF, leave the car to run on your driveway or whatever. leave bonnet open. Watch temp gauge. When it gets silly hot (100 / 105?) do the fan(s) come on - the ones on the outside of the radiator? No = fan relay. Yes, but still overheats = viscous fan coupling.

Just to clarify, theres almost always TWO fan systems, one is bolted to the engine via a gloopy sort of oil operated clutch. As the engine gets hot, it makes the fan spin faster and faster. If this is knackered, its just freewheeling like a windmill, and thus not doing much cooling. You can very easily chick this is ok by getting a small twig or a carrot, and when the engine is hot, can you stop the fan? Be careful not to have any loose clothing / hair anywhere near it - just the twig or carrot. (The carrot is used as if you can stop it without breaking the carrot, its knackered. If you have carrot puree, then its OK.) The second fan system is a 'normal' electric fan. This is controlled by a relay (box like switch thing) which is 'told' to fire by one of two things. 1) the engine is too hot, or 2) the air con is on. With a little thinking, im sure you can work out if its the relay (ie doesnt fire up fans at all, ever) - or its the sensor (fires up fan for the air con, but not the engine)...

Good luck.
relay fans have been upgraded by mbz they are a known faulty item and this is why mba will not sell onw with out a chassis num to go with it ie they are keeping records
ml270 radiator fan doesnt come on

Hi sorry this is my first post on this site not sure how to use properly anyway have mb 2001 and the radiator fan wont come on been hooked up to computer says its the relays been changed but its still not coming on any help gratefully recieved thanks.:dk:

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