A/C viberation

[stephen p luce]

So I put a 97 vortec long block in my 89 K1500. I used the steel horseshoe bracket for the accessories and ever since the a/c compressor vibrates when turn on. I checked all the mounting bolts are there and tight and the compressor support brackets that run to the intake manifold are in place. Blows nice cold air but I'm afraid something is going to brake and it sounds horrible. Anybody have any ideas? I thought maybe going to the cast aluminum brackets might fix it but haven't found any close by, pick n' pull is a hour and a half drive from me.

 

[evilunclegrimace]

Did it vibrate before you swapped engines? Is there a crack in the mounting bracket? Are all of the pulleys in alignment? Is the compressor clutch damaged. Is the belt tensioner in good shape,not worn/ loose? Does the compressor have a bent shaft?

 

[GoToGuy]

Did you drain and recharge AC by any chance when you did the swap?

 

[Schurkey]

The brace from the back side of the A/C compressor that secures to the intake manifold is in place?

No idea why having a Vortec long-block should make a difference. Something other than the long-block is the likely source.

If the tensioner arm jiggles, start with replacing the tensioner.

 

[Erik the Awful]

The A/C brace goes to the bolt holes in the middle of the intake on a TBI. If you put a Vortec long block in it there are no bolt holes for the A/C brace to go to. That's one of the things I will have to re-engineer if I ever fix the A/C in WCJr.

 

[Schurkey]

The A/C brace goes to the bolt holes in the middle of the intake on a TBI. If you put a Vortec long block in it there are no bolt holes for the A/C brace to go to.

Depends on what intake manifold is used on that long-block.

 

[stephen p luce]

Thanks for the replys guy's, sorry I haven't been back for a few days, life gets in the way To answer everyone's Q's. no it did not vibrate before engine swap, 2nd new compressor, with new belt and tensioner, I see no cracks in the bracket the support braces are all there, had to modify them a little bit but they are there. yes it was evacuated and new r134 added, I believe it was 28oz to fill it. I used the after market intake designed for the TBI to Vortec conversion. Yes the pully's look all lined up. Summers coming and I would like to have my a/c back in operation. It blows 40* air when it runs just rattles and vibrates loke crazy.

 

[stephen p luce]

Am getting tired of not having a/c in the summer. I am wondering if I can use '96 suburban accessory brackets. I know I would have to redo a couple of the a/c hoses and some of the wires would have to be extended. I just cant find the source of the vibration . I have 2 '96's here that I could get the parts from. What do you guys think.

 

[GoToGuy]

You identified it's the compressor vibrating? By touch? When the 134 was added you did the vacuum down and leak check, then reserved the 134, and added the correct amount PAG oil right? Can you post a pic of compressor side view, and rear shot? Where did you obtain your new compressor? Good quality?
Did you do R134 conversion on your system? Since it's pre 134 ?

 

[stephen p luce]

yes by touch. I can plug and unplug the compressor and make it go away or vibrate. I did the conversion years ago and it worked well until I installed the vortec engine, then the vibration started. Bought a new one from NAPA checked the oil level, evacuated and recharged wit 28 oz r134. New belt and tensioner and idler pully. I checked the horseshoe bracket before I put it all back together. I have the two support rods attached to the back of the compressor and the one to the backside of the alt. Just don't know where to go next. I acutely changed the compressor twice as I thought maybe I got a bad compressor. Another strange thing that recently happened was the pully for the p/s pump broke out around where it presses on to the pump, never saw that happen before. replaced pully and a/c vibration still there.