Thread: basic A/C clutch question

the washers are to adjust the air gap of the clutch.it just needs to clear.

the crack isnt important--its a corklike stuff to help demagnitise the clutch.when it gets hot it falls apart or burns.its glued on.

have you checked the magnet coil.

Probably outta gas. First thing you check is if the clutch actually works. hot wire the clutch and see if it cuts in. You can also temporarily bridge the hi/lo pressure switch but don't do it for any lenght of time with the engine running or you'll damage the compressor.

There are 2 switches on the thermostat housing , one of them is normally open, one is normally closed. one switches on the A/C blower fans operation when the engine overheats, the other switches OFF the compressor clutch to avoid adding more load to an overheating engine. I have seen the compressor switch off switch fail and go permanently open circuit after an engine was very overheated. This was tested by bypassing it and presto all was OK with the compressor clutch.

Check those front switches, also there are 2 fuses, 1 under the dash and 1 in the engine compartment fuse box for compressor clutch and blower fans.

JC

Thank you all so much for you input!

Having spent the rest of the morning checking the electrics surrounding the compressor I found exactly what justinc was suggesting, a fault with the compressor cut out switch.
BUT it seems to be a curse either on me, or on my disco.... it NEVER IS THAT EASY.

Reason for my frustration is: part of my last overheating repair was to replace both compressor cut out and thermo fan switches (since I did not know at that stage what had caused the overheating I just wanted to make sure sure...)
and well here we are apparently again with faulty parts.
First I thought that maybe I got two fan switches since both were open when measured with a multi meter, but once the engine is up to temp the fan switch closes, but the other one remains open.
After finding that, I simply went out to buy a new switch, but on my return home - and lucky I didnt go ahead and replace the ****er - it also tests to be open.



Fuses are both OK, and compressor clutch also engages when bypassing the cut out switch, so all I have to find now is a working switch.

Can anyone confirm a part number for me, since I am still puzzled as to why I got two brand new OPEN cut out switches. Both with the part number PRC3505.
Also with the other switch I am wondering now, for I have read the fan switch is supposed to close at 100 C rising. The TM2 reading on the block has not exceeded 90 yet. Is the difference between coolant temp and block temp that great? And if so, should the coolant be at 100C? or could this also possibly be a faulty or wrong switch? (part number for the one I have is PRC3359)

THANK you all so much again!

Hi

Maybe you can help me. I've just poste my question under Discovery2 but it related to the Denso A/C Comp Clutch.

Can you inform me the specifications of the bolt and shims/washers you used to asemble the clutch plate to the rod/axle. And any further relevant infor like freeplay between the plates etc.

Thanks in advance
Ulrich

Hi Ulrich!
I'm afraid I personally can't answer your questions. I reused same bolt and washers, and as to freeplay and mentioned air gap - all I can tell you is that mine spins freely when in place with approx. 2 mm gap between the front plate and compressor.
BUT whether or not these are the exact specs, I don't know.
Probably best to wait for a reply of someone who knows about it!
Sorry to be such little help and good luck!

I found shims still inside the clutch plane mounting part – so I took my changes and tightened the clutch plate to check clearance in practice. Turning off the A/C (Econ) and clutch plate wasn’t engaged. Turned on it was engaged and rotating – concluded that it was fine.
A/C works fine now :-)
/Ulrich