CDTI cooling fan

[bsafly]

I recently had a new fan fitted to my 2003 75 tourer (to replace the three speed fan of which no speeds worked) so I could get the air conditioning up and running which has never worked all the time I've owned the car.
Had a full air con service and re-gas today, they gave the system a thorough going over and no found faults or detectable leaks (the company I used are air conditioning specialists with good reputation who i have previously used for a regas and service on my ZT-T 190 two years ago and that is still working well).
The journey home was lovely with nice cold air and the ATC doing its job well, however when I arrived home and got out of the car to open the gate the cooling fan was extremely noisy which seemed odd as I had done the demist test after the new fan was fitted and it operated nice and quietly. A quick inspection through the grille showed no debris etc caught in the fan
I parked the car up, turned it off and left it whilst I had a coffee, on returning to the car carried out the demist test - the fan was running nice and quietly as expected, however as soon as the auto button is activated on the ATC control the cooling fan ramps up to high speed and runs at that until the air con is turned off.
Does anyone have any ideas as to the reason this happens, my thinking at the moment would be incorrect wiring of the new fan or trinary switch fault, suggestions gratefully accepted.
Many thanks, Paul.

[SD1too]

Hello Paul,

It's been hot today so it could be that your air conditioning just had to work harder to maintain your selected temperature (did you have it lower than 19 degrees?). The other possibility is that your condenser is past its best.

Did the air con. specialist maintain a vacuum for 30 minutes before recharging?

Simon

[bsafly]

The specialist held the vacuum for an hour on my instruction as i didn't know the condition of the system and wanted to be as sure as possible that there were no leaks before gassing it up.
As I say the system seemed to work well on the return journey, but the fan running at full speed when I got home was so loud it drowned out the sound of the (diesel) engine at idle!
I've just been out to the car and checked now it is cooler outside and the fan only runs at slow speed initially (so I guess the system could just have been struggling with the heat today as SD1TOO suggested), however during checking I noticed an intermittent noise which suddenly became constant whilst the air con. is on and disappears when the air con. is switched off or the engine revs are brought up from idle - guess i will be fitting a new crankshaft damper shortly, although this one appears to have survived just over 170,000 miles so I can't really complain.
Might as well physically check the condition of the condenser and change that if it looks like it has shed any of it's fins even though it didn't leak under vacuum test.
Just off to price up some parts!

[T-Cut]

Originally Posted by bsafly

Might as well physically check the condition of the condenser and change that if it looks like it has shed any of it's fins even though it didn't leak under vacuum test.

Hello Paul, loss of the condenser's fins dosen't mean it won't hold vacuum. The fins are more or less held on by friction, so will wipe off or even blow off after a few years of weathering.

Here's everyone's favourite foto.



I've no doubt this one was vacuum tight. Run a finger across the fins located in the area covered the fan blades and across the bottom edge. I suspect you'll be surprised.

TC

EDIT: Foto by Jules

[roverrich73]

Hiya

I have a 2004 facelift cdti tourer, similar fan issue - it only comes on at high speed - turns out in my case Rimmers supplied me with the wrong fan - i needed a 2 speed and they sent a 3 speed - the garage that fitted it didn't really know the car so thought nothing of the car sounding like the hovercraft - so may be worth checking you have the correct fan!

[bsafly]

Just been out and pulled the 75 bumper off, the condenser looks just like the one in T-Cut's photo, but with less fins!
Also took the chance to inspect the crankshaft damper, although it looks ok visually it has slight run out when the engine is running and the noise under load disappears when the front face of the damper is squirted with water so I have no doubt it is requiring replacement.
Spoke to the specialist who did the air con. service and he is happy to de-gas the system so I can change the condenser and providing no gas has been lost there will be no charge for gas when the system is re-gassed, can't really complain at that!

[Arctic]

Hi Paul.

I changed one out yesterday not my car but a fellow members removed and fitted condenser & fan.

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I struggled with one of the crash bar bolts for at least 15 minutes as the welded nut had broken free, which is in an awkward place behind the crash bar and in a recess, add the fact its a square welded bolt with with four chamfered edges, in the end i managed to just about get some long nosed mole grips on to it.