ScrapMaker

I have run out of options here...

About a month ago I replaced my A/C compressor because it was leaking out Freon, and as soon as I was done putting it on, my tensioner started bouncing like crazy and making a very loud, annoying banging sound.

First thing that came to my mind was that the tensioner was bad, so I went back to the shop that replaced it 2 months ago. The mechanic told me straight up that it was my compressor, but replaced the tensioner anyways, just in case.. well, that didn't help the situation whatsoever.

So just today I got another compressor (all of these are brand new BTW,) and installed it properly, including flushing the system, and pulling a vacuum for nearly an hour.

I put the PAG oil in the compressor before I mounted it and turned it by hand, roughly 8oz. I put in 2.5 cans of r134a to get as close to 29oz as I could.

At first the system was quiet and I was happy, but after driving on the highway for about 10 miles, and parking at the autozone to return the old compressor, I started getting that loud banging sound at idle... this is the ONLY time I get the loud banging...

I have the stock belt configuration with a brand new alternator, water pump, and the engine itself is only 2 years old.

What other component could it be on the system that is causing the rattles? Smog pump? Also, how easily should you be able to rotate the compressor by hand before you install it, or even once it's installed? I ask this because both of these new compressors were VERY hard to turn by hand, which is what I thought was causing the tensioner to vibrate... (the clutches are not adjustable, that was the first thing I looked into.)

My old leaky compressor was very EASY to turn by hand, if that helps.

The compressor I have installed right now is a Delphi, so shouldn't that be fine?

Thanks in advance, because I'm starting to lose hair over this matter... luckily my mechanic friend does not charge much for this kind of work, otherwise I'd be at least $1000 in the hole right now.

-Steven

ScrapMaker

is it possible it's only a pulley on one of the other components? because I can turn them all by hand relatively easy.

black89ws6

does it bang all the time, or only when the ac compressor is engaged

ScrapMaker

it only bangs when the compressor is engaged, and only at <1000rpm..

and it doesn't happen ALL the time, but when it does happen, the sound you are hearing that is the banging, is the tensioner flying around... its like something on the system is putting extreme resistance on the serpentine system...

I thought it was the tensioner at first, but even the guy replacing it told me it was the compressor... so I had it replaced, with a different brand entirely... same problem...

tomorrow I will take off the belt and turn all the components by hand and feel the pulleys to make sure none are loose.

Is it possible that the added strain on the system by the compressor is causing another (like the PS pump,) to wobble or vibrate, or become highly resistive which makes the tensioner wack back and forth?

black89ws6

How is your belt tension? Serpentine belts stretch more than v-belts. If your belt is worn and stretched, even though there's a spring tensioner on your system, your belt tension will be reduced.

New compressors should feel much tighter than old ones, that much is normal. You should be able to turn it by hand, though. When you turn it by hand, pay less attention to the overall tension you feel in turning it, and pay more attention to looking for any spots where the compressor seems to lock up. If it drags quite a bit, at the same spot every time, you may have a problem.

If you try to turn it by hand, after it's installed and charged, expect it to be much harder to turn than out of the box, although if the ac system has been off for 10 minutes or so, it should still be possible to turn it by hand.

I don't think your problem is in any other accessory. Alternators and water pumps tend to either turn ok, or lockup entirely. I've never had a problem with a steering pump, so I can't say anything about that. As for the smog pump, I know they can lock up, but I've never seen one do it. If any of your accessories have a bearing going out, you should be able to feel it if you spin the pulley by hand.

ScrapMaker

you got me thinking, my belt is definitely worn out... if I replace it, maybe it will tighten up enough to help the situation...

it never vibrated with the old compressor, but that didn't 'compress' much, as it was broken....

ScrapMaker

well... interestingly enough, I fixed the problem. It WAS the tensioner making the noise, as I knew all along, but I couldn't figure out why exactly it would only make the noise when the A/C was on.

So I went to AutoZone to get another tensioner, and partially because of black89ws6's post, and partially because I knew I needed one anyways, I got a new belt, (the cheap version, I don't think there's much difference.)

I decided to put the new belt on before I pulled off the old tensioner, just for grins. The sound went away, but the tensioner was still moving violently. I looked closely at the tensioner, and the plastic seal in the middle was actually SPINNING for some reason!

When I pulled it off, the bearing was obviously shot, and I could wobble it around like crazy. After I replaced this, and the belt, my problems were over.

I am still a bit curious as to how my tensioner died in less than 3 weeks. Could the old A/C compressor have caused it, being so hard to turn?

Thanks for the ideas and help,

Steven

ScrapMaker

Just for comparison, with the old belt on the system, and the a wrench on the tensioner moving it as far as it can go, I could fit about 3 fingers between teh belt and the pulley on the alternator. Now I can hardly get the damn belt on the alternator!

Dizturbed One

isn't that you're third tensioner?

something is making you eat tensioner's, no way is it the tensioner if that's your third... I'm betting you'll get the same problem awhile down the road unless I read something wrong or took it the wrong way.

check the electrical connection that engages/disengages the clutch on top of your compressor, follow the wire back and see if it has been damaged during one of you're compressor installs.

mine started eating belts BADLY because of that

and about a month after I fixed it the tensioner went out after taking that kind of abuse.

ScrapMaker

well what I believed happened was that the last compressor I had in there, which was only in for one month, and I hardly used it, destroyed the tensioner some how... but also, like I said, the belt was literally an inch or two longer than it was supposed to be... there wasn't enough tension on the belt system, and when I had the A/C on while going slow and turning, I could feel a weird vibration from the the steering wheel, like the PS pump acting up... now that I have the new belt, it feels great.

I'll post in here again if it fails, but if it does, I can't see what would cause it... it would have to be the smog pump, although every component on my car spins freely, no problem.