Had AC compressor replaced. now the dampers groan

[navyjoe]

I just had to replace the AC compressor (and dryer/orifice) on my 06 3500. Now when I get in and start the truck with the AC on, the damper doors pop and shudder (strange sound, hard to describe) about 6 times before they settle down. When the AC cycles off a damper noise occurs again. There was no noise before it had it fixed, and the repair work was only under the hood, not in the cab (right?). What might the reason this started just after the repair. Could it be a vacuum problem? any vac lines in the area of the compressor / dryer / orifice tube?

 

[BDaugherty]

06 uses electric actuators for all the blend air doors...no vacuum at all. I don't see any relation between blend air door problems and a/c hard parts other than you probably didn't turn it on much when the a/c wasn't working. Anytime I do blend air door work, I use heatertreater parts. Also, see their site for reference to your specific problem.
http://www.heatertreater.net/index.html

 

[navyjoe]

06 uses electric actuators for all the blend air doors...no vacuum at all. I don't see any relation between blend air door problems and a/c hard parts other than you probably didn't turn it on much when the a/c wasn't working. Anytime I do blend air door work, I use heatertreater parts. Also, see their site for reference to your specific problem.
http://www.heatertreater.net/index.html

BDaugherty,
Thanks for that information. I'll probably be needing to do that repair in the near future with the truck being 8 years old. I now know to look elsewhere for sure. It did not seem reasonable to be a damper but it is related to the work done. My AC quit while going down the highway. It just turned off. When I got to my destination I started troubleshooting and found the clutch coil had opened. I'm on vacation with no shop facilities so I just decided to not bother just trying to replace the clutch and waiting a week to get the part in and trying to do it myself. Two days later I had it fixed and this problem started immediately after that.

In fact I just came in from driving it in stop and go traffic and it happens anytime I start the engine and go, or take it in and out of gear (neutral/park to drive) It sounds like it is coming from under the dash on the passenger side, but based on what you said I now strongly suspect it may be vibration from a missing mechanical fastener or something like that vibrating on the firewall. So now I going to pop the hood and look for something obvious. If not I will have to take it back to the mechanic.

By the way to anyone reading this thread the whole job cost $930. Compressor, dryer, orifice tube, misc parts and labor. I took my truck in at noon and had it back by 5.

 

[navyjoe]

Ok, found the problem. The new orfice tube is only about 1/8" from the oil dip stick tube. When you go from neutral to drive (or accelerate just right) the engine twists slightly and the oil dipstick tube briefly contacts the AC line that does into the cabs evaperator which makes it sound like it is coming from under the dash. Can't say it is the mechanics fault but I wonder if there used to be a rubber sleeve on the AC line or something that prevents it from contacting the dipstick tube. Anyone got an 06 truck to see what yours looks like? Again the metal AC line and the dipstick tube are only 1/8 to 1/4 inch apart

 

[BDaugherty]

Either tweak the a/c line away from the stick or wrap a short section of heater hose around it and zip tie it to the dipstick tube
The orifice comes made into the liquid line and it's not super easy to install without a little tweaking so I really wouldn't worry too much about it now that you have your diagnosis.

 

[navyjoe]

i'm a little reluctant to mess with the new installed line since if I mess it up it would void my warranty (unless the mechanic does it) . I think I will go with the heater hose solution. Good idea. Thanks BDaugherty.

 

[navyjoe]

Well I tried the rubber hose. The line and tube are so close together that putting on the hose cover causes the two to stay in contact and that causes a permament noise inside the cab. So the question. Which is easier bending the AC line or moving the oil dipstick tube? Can the dipstick even be moved? I know some of them are held by a plate with a screw and are adjustable. Don't know if that is true on this truck or not. I've read on another post that someone just bent it over and that caused some trouble. Would like to know which is the best approach before I take it back.

 

[navyjoe]

Well I tried the rubber hose. The line and tube are so close together that putting on the hose cover causes the two to stay in contact and that causes a permament noise inside the cab. So the question. Which is easier bending the AC line or moving the oil dipstick tube? Can the dipstick even be moved? I know some of them are held by a plate with a screw and are adjustable. Don't know if that is true on this truck or not. I've read on another post that someone just bent it over and that caused some trouble. Would like to know which is the best approach before I take it back.

Also wonder if I should redo this question as a separate post and reference this one?

 

[BDaugherty]

Just bend the a/c line away from the tube a little...that's all the mechanic would do.

 

[navyjoe]

OK, thanks. Again thanks for the help.

 

[Tuesdak]

Run it back by the shop that did it and ask them to solve the problem.

If you do do it by yourself be safe and wear gloves and goggles just in case the line breaks and vents nearly 2lbs of freon and oil that can cause frostbite and/or blindness. The system sits at around 150 PSI and when running can be around 350 PSI. Also do this is a well ventilated open garage or outside as R134a displaces oxygen. Avoid any open flames like smoking, a gas water heater, or Bar-B-Q close by as R134a turns toxic when burned.

Like anything AC systems are easy to work on if you know the dangers and respect them. Hopefully folks know this and I am just reminding them of safety first.

 

[navyjoe]

Thanks JDoremire,

I very much agree to let them do the work if for no other reason than if I do anything it would void their 1 year warranty.

I would like to know however if the dipstick tube is adjustable at all. If it has the ability to rotate a few degrees upon loosing an attachment plate that would be the easiest fix. I have not done any major work on a Cummings engine at all (and at my age don't plan too), but some of the other engines I have worked on in the past did allow this.