When I start my "06" CTD about 2-5 seconds after it starts I hear a noise that sounds just like the air-conditioner clutch engageing. It does it even though A/C it is off. What could be making this irritating noise? All works fine after that.

 

I am having a hard time finding it in writing, but I think the pcm will cycle the compressor to keep oil circulated even if the a/c isn't on. i read it somewhere but can't find it now. It all has to do with compressor dependability.

 

VZ.....It sounds exactly the same as the A/C engaging. Your explanation makes sence. Also I have not been using the truck much and it may set for a week or 2 before I use it.

 

Finally somebody else that is having the same thing happen to their truck. I've posted it on here a couple of times but nobody knew what I was talking about!!! I think we have the only 2 trucks in the country that is doing this! Mine will only do it if I was using the AC on my previous drive. If I wasn't using the AC then it wont make that annoying clunk the next time I start it up. I have had my wife start the truck while I watch the compressor and sure enough it engages for about 3/4-1 full turn even with the AC OFF. But like you said other then that it works perfect.....Anybody have any clues????

 

Make that the only three trucks in the country, I just noticed mine doing that a couple of days ago. It's been pretty hot out here and I just figured it was the AC until the other day it did it and I noticed the AC wasnt on.

 

my '05 and '03 dont' do that... is the defroster on??? the clutch will cycle with the defroster on...........yes i know its hot outside....

 

I live near PHX. I dont think I have used my defrost more than 3 times total. BTW I dont think that would make a difference cuz if the fan is in the off position it wouldn't matter which position the vent setting is on, the system is completely shut off.