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Overheating. Fans & AC not working


C.J

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I drove 30miles yesterday, and when arriving at the top of a multi story car park, my temp gauge was maxed out, and the engine was showing white smoke. Upon pulling over and checking the bonnet, I could see coolant overflowing from the overflow pipe in the bottle.

 

I let the car cool down for an hour and topped up the coolant. I checked the fans, and neither were working. I turned the AC on, and no fans came on (I thought a fan should come on at all times with AC?). I took it to the nearest Kwik Fit (ssshhhhh) who thought my AC may have been empty and causing the fans not to kick in, so they regassed it for me, still no AC, but they didn't charge me.

 

I've done the 10button door switch test (wipers/lights/fans) and they either don't spin at all, or one each randomly.

 

Today I've taken the car out, and as the temp increased again (at standstill after 20miles) the fans didn't kick in.

 

The symptoms:

 

1. No AC (but full with no leaks)

2. No fans

3. Overheating

 

The possibilities are (from my research online):

 

1. Thermostat (but would this cause the fans and AC not to spin?)

2. Fans, fan motors, fan clutch?

3. Head gasket (Kwik Fit checked for this, no sign of it, so highly doubtful)

4. Radiator

5. Coolant air bubble

 

Any advice welcomed and ideas for testing and eliminating.

 

Also, I'd like to say thanks to a fellow 350z owner who did stop and check I was ok.

 

A picture of mine for the rubber neckers ;)

 

08fca679.jpg

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Not going to be much help tracking the fault I'm afraid - but when mine did this about 2 years ago I had it checked over by the local garage and they said thermostat OK etc, it was the fans which weren't working.

 

Trying to buy fans from a breaker in a limited time proved unsuccessful, and I ended up paying £600 for the unit (2 fans mounted on the whole section from behind the radiator,) plus fitting - all at Nissan Stealers rates.

 

I had to pay it as I needed the car and didn't have the time to wait searcing all round for a second user unit -

 

I hope you have better luck than I. If not - prepare yourself for an unpleasant attack on the finances

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Pretty sure this is the fan motors.

 

Start the car and let it run for several minutes. Tap the centre of the fans (where the motors are) taking care to avoid the blades. If the motors are at fault they may well start after a sharp tap.

 

Alternatively, start the car, put the aircon on and tap the passenger side motor to see if it starts. I think the fan always kicks in when the aircon is on regardless of water temp.

 

My local dealer wanted £700 for the replacement fans, Zmanalex got them to me far cheaper. Fitted them myself, it's an easy job. I kept the old motors and will investigate re-conditioning them at some point, even though they are sealed units.

 

Good luck. :thumbs:

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Thanks for the quick replies B)

 

I've dropped it off at my local Indy to double check for me, and I'll get a PM off to you ZMANALEX if it's the motors. :thumbs:

 

I'll update with my findings.

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Motors come apart easy.. the brushes get stuck and need dressing with a needle file..easy job

 

Can you expand on this please? Are you saying that you can "fix" the duff motors by using a needle file to file down something to ensure the brushes move more freely? Can't be that simple can it or it would be all over the forum?

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Ok, a quick update/question.

 

The garage I dropped it off at on Tuesday, have told me today they've ordered a new 'temp switch'.

 

Any idea what he means by this (thermostat?), and if this is likely to be the problem with my symptoms? Could the thermostat cause the AC not to work and fans not to spin?

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Ok, a quick update/question.

 

 

 

Any idea what he means by this (thermostat?), and if this is likely to be the problem with my symptoms? Could the thermostat cause the AC not to work and fans not to spin?

 

 

Thermostats can fail in 2 ways, they can fail to open and overheat the car or they can stick open and the car will take an eternity to heat up especially in the winter. I can't see how either of these problems would cause the fans not to kick in though :shrug:

 

 

Pete

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I've no idea what's been checked. I'm adamant it's the fans at fault, hence the intermittent spins during my tests and AC not working.

 

Would the thermostat cause the AC not to work too?

 

Hopefully I'll get it back tomorrow, and will try some of your suggestions (tapping the fan when AC on).

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It will be the fans very easy repair and Alex will be the cheapest place to buy, mine went two years ago bought two fans took about one hour to change and have had no problems since.

max.

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Cheers.

 

I've got the car back now. The fans are intermittently kicking in still, sometimes with AC, sometimes not at all.

 

I'll do some tests over the weekend before deciding what to do.

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  • 3 weeks later...

Can I have some more advice please :blackeye:

 

I still don't have the car back, and I've been told today that it's "both cooling fan resistors, need new, aprox £550 just for fans".

 

Does this sound right? If the 'resistors' have gone, I'll need new fans?

 

Moving house tomorrow, this is all I need.

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New fan motors in stock and good to go same/next day :thumbs:

 

viewtopic.php?f=157&t=48509

 

Alex :)

 

You're going to have to help me, he's quoted £550 for the fans (I assume this is 2 fans with 2 motors)

 

Your price is £200 per motor (£400 for 2). What's required to fit the motors to the fans, as the difference is £150.

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