Expert: Roland Finston - 11/7/2011

Question
QUESTION: Hi Roland

I have a 2002 grand voyager 2.5 crd, the air con pulley has started to make some strange noise's to the extent I have had to call out the local recovery firm, they say the pump or the pump clutch is going but are unable to establish which, is there a way to tell ? Is there a conversion kit to by-pass the pump alltogether ? and finally if the pump/clutch siezes what would be the ramifications.

kind Regards


Mark

ANSWER: Hi Mark,
The noise, if it were the clutch mechanism, would probably be present when you didn't have the AC 'on', whereas if it were the pump it would more likely make noise only when you asked for AC. So if it is making noise when you aren't asking for AC then try replacing the clutch.
I don't have a belt diagram for that engine, but it could be possible to by-pass the AC unit by using a shorter belt. But try the clutch first if that appears to be the issue.
If it seizes, the belt will wearout quickly due to friction and then everything that is driven by the belt will stop working. Again without know what else is driven by the belt I can't forecast what will happen.
Roland

---------- FOLLOW-UP ----------

QUESTION: Hi Roland

Many thanks, the noise come on start up of the vehicle only then stops, this is without the air con on, I am not sure if this means anything in terms of problem.

Kind Regards


Mark

ANSWER: Hi Mark,
So long as you don't have the 'defrost' button activated at start up (which also causes the AC pump to be driven) then only the clutch bearing would be in play at start up so that would point to the clutch as the issue were that the case. The clutch bearing would then be likely in the process of failing so pretty soon the noise will not stop.
On the other hand, if you do have the defrost activated and if it stops and then starts up again  then I would think that the sound is coming from the pump which cycles on and off normally as it is used in either the defrost or the cool position.
Roland

---------- FOLLOW-UP ----------

QUESTION: Hi Roland,

I believe its the pump, I have been away for the last few days and the car has been left on the drive, however I have just tried to start the car
and the engine wont turn over, I have ignition and a good battery, when I dip the clutch and turn the ignition switch the lights dim but nothing turns, I have replaced the started fuse just to make sure. I think its a standard 2.5 turbo diesel set up with the alternator being run via the same belt,

If the pump is seized would this affect the failure to turn over or do you think I may have overlooked something else ?

Kind Regards

Mark



Kind Regards

Answer
Hi Mark,
If the compressor were seized that would still not stop you from starting the engine because the compressor is not connected to the clutch pulley unless you have air conditioning on and the engine is running. About the only way the air conditioner compressor could stop the engine from being turned over would be if BOTH the compressor and the clutch had failed in the locked together position.
The clutch pulley could however be seized based upon our earlier discussion.  So I would suggest that you check to see if the engine can be rotated by hand using a socket on the crank pulley bolt and a ratchet handle to test that theory. If it won't rotate by hand then the a/c clutch may well have failed.
Or if you don't have the tools to do that if you had the tools to loosen the tension on the drive belt of the compressor so that it would slip, then you can try to start the engine and see what happens. Don't run it that way of course for any length of time.
If the engine will rotate by hand then I suspect your battery is weak or the starter motor is weak, probably the former rather than the latter. Then try a jump start or recharge your battery.
If it will only start by loosening the belt then the clutch pulley bearing is locked up.
Roland