75ZT Community

CDti auto

Recently developed a slight drone over the engine revs, but only when air-con is switched on.

Had the unit serviced and re-gassed yesterday (specialist I've known for many years) mileage now 51k.

Needed PAG oil to the compressor, which has almost cured the problem (it still occurs spasmodically on tick-over when it's hot outside say +80F).

However the dreaded fan blight may have struck me, as it is apparently only operating on the high speed) I'm told by the technician, (not a River specialist).

In parallel my mpg has recently dropped about 10%. I presume because the fan is cutting in on high, and reducing the engine temperature below optimum, and also must take more energy to run anyway?

I think with a late Dec. 54 reg, I only have (had) a 2 speed fan anyway?

Does the said fan only cut in with air-con on at high speed only?

Could the other speed still be there for engine cooling anyway, and is still operating, and is there a way to find out?

Hi Martin,

Mine is also a 54 reg ( facelift ) and i had the fan issue recently, to test switch on the ignition and set the ATC (Automatic Temperature Control) to demist by hitting the demist button, the fan should then work on low speed, if it doesnt chances are your resistor is shot, available from Jules at a very reasonable price ( around £15 from memory ) not difficult to fit but bumber off job for a facelift, hope this helps

Slow speed failure is not an actual fan failure, it is the external resistor that has gone open curcuit. simple enough once the bumper is off . get one from Jules pre drilled and tapped with all the correct connectors

Trebor wrote:Hi Martin,

Mine is also a 54 reg ( facelift ) and i had the fan issue recently, to test switch on the ignition and set the ATC to demist by hitting the demist button, the fan should then work on low speed, if it doesnt chances are your resistor is shot, available from Jules at a very reasonable price ( around £15 from memory ) not difficult to fit but bumber off job for a facelift, hope this helps

Thanks Trevor,

Just tried it viz;

Engine off ignition on, hit demist - on the fan scale right up on high.

Turned down the fan manually - turned off.

Repeated again hit demist - fan as before High setting.

Is it more likely to be a resistor, or a complete fan change? (mileage 51k)

Wrong fan Martin, the fan you need to check is the one behind the front grill, not the one in the cabin, sorry if it was not clear

The fan you are hearing is the heating fan - you need to get outside the car and see if the radiator fan is working or not.

takestock wrote:Wrong fan Martin, the fan you need to check is the one behind the front grill, not the one in the cabin, sorry if it was not clear

Hello and thank you,

I've just done that and with the engine ticking over, hit demist fan and rad fan cuts in on the high setting

Jules is away for a few days at the moment, I've emailed with him, and I am due to be passing his location, within a month or so, so I think it's better to visit him, rather than just order a fan, and get it fitted my end?

At least in that way, we'll find out if I need a fan replacement or resistor / upgrade replacement only?

He did mention that my spasmodic 'whirring' with the the air-con operating, may be a condenser failure which is very expensive. I had the air con serviced Friday, and the noise seems to have almost gone following the PAG oil being topped up in the compressor (1/3rd down).

However whilst parking up from having the job done (20 mile run back) the 'whirr' did re-occur at tick-over. On the road it's gone, hopefully it may clear completely with a few more miles covered?

Thanks again for the help

MrB wrote::iagree: The fan you are hearing is the heating fan - you need to get outside the car and see if the radiator fan is working or not.

Thanks Chris,

I've tried this and it cuts in on high, hopefully it's a resistor upgrade from Jules.

Martin

Hi Martin, sorry to hear you have problems, get Jules to send you an upgraded resistor, book it into Chelmer Rover and come and have some lunch at ours while its being fitted. Dave

Dave,

What a champion idea, I'll email Jules and order the resistor. Soon as it's to hand I'll call Chelmer Rover arrange a time and give you a ring.

See you soon,

Martin

(By the way did you know GB Fuels now own both Flitwick and Bayford Thrust (Gulf Retail) !!

Thats a date! Or it will be when we know when the date is! Dave