Ok no one is responding and I don't know sh-- about a/c systems...but have you ruled out the clutch making the noise?

 

Ok no one is responding and I don't know sh-- about a/c systems...but have you ruled out the clutch making the noise?

Not really, but would think if clutch is the problem it would do it all the time.

 

clutch bearing going out , mine did this before locking up , mine was a sanden unit . when the unit is disengaged it makes a makes a light metal grinding noise at the plates .

 

You mention that everything was replaced back in 2007? Does that include the condenser as well? Reason why I ask is because metal fragments from a previously bad compressor could be in the system and effecting the new compressor. Secondly, who made the compressor that you installed? I have found out through experience that good ac parts are very hard to find and try to stick to oe as much as possible. As I type, I'm taking a break from installing a new compressor in my 96 mercury. It went after 150K. Since I'm supplying the labor, everything in the system is being replaced with OE equipment. It might cost more but I know its an exact fit and a quality part. FOUR SEASONS petrifies me.

 

You mention that everything was replaced back in 2007? Does that include the condenser as well? Reason why I ask is because metal fragments from a previously bad compressor could be in the system and effecting the new compressor. Secondly, who made the compressor that you installed? I have found out through experience that good ac parts are very hard to find and try to stick to oe as much as possible. As I type, I'm taking a break from installing a new compressor in my 96 mercury. It went after 150K. Since I'm supplying the labor, everything in the system is being replaced with OE equipment. It might cost more but I know its an exact fit and a quality part. FOUR SEASONS petrifies me.

The only thing that wasn't replaced was the evaporator, I flushed it very will. The original compressor did not go bad, just replacing everything with new. Old compressor had 157000 miles on it. The new compressor was bought at Autozone, it was the best one they offered.

 

Stiil, I think your compressor might be starting up. We did a compressor one time on a '78 Chevy and it was shot within a year. What brand did you buy at Autozone.

 

A couple of thoughts. I would not add any more r134a as your pressure is already getting high and you can easily add too much r134a. If it cools then leave it as is. Secondly, does it make this noise with the compressor off? If it does then if you can isolate to the compressor (which is not easy) then the clutch bearing is probably bad or warped clutch. I have seen this many times. If it only makes this noise with clutch engaged then the compressor is most likely at fault. It could have bad compressor bearing and/or an issue with the compressor valves. Assuming that you did a long vacuum pull down (at least 1 hour) to remove moisture. Also, assuming you put oil back into the system. Many compressors come with oil but many times not enough for the entire system.

 

12oz of oil was probably a little too much, 45L/300H is probably a little too much refrigerant. 35L/225~250H are the magic numbers for me. You do know that when changing over an R12 system to R134a, you should use about 20% less refrigerant? Was the compressor a reman or new? I will NOT use a reman unless there is no other choice. I'd almost prefer a "known good" used OEM one to a reman. What I would do if I were you is suck it back down, replace the orifice tube with a VOV, (variable orifice valve), or "SMART" orifice, and recharge with the proper amount of Freon. The VOVs help the system cool better, and make compressors live longer as well. Is this in your S-10? Hot-rod motor? Sometimes more radical cams and the natural pulsing of the A/C system are a little out of sync, and can cause some belt noise that sounds kinda like a rumbling, the fact that it goes away at a slightly higher idle tends to indicate that that may be the problem. Let me know if I can help,

 

Thanks guys, I think it's something with the compressor too. The clutch is good. It only does it at extremely low RPMs, like in gear, AC on, stopped. I need to put a fast idle solenoid on it to keep the idle up with the AC on.

When it does this, which is anytime the above conditions exist, it almost sounds like noise is coming from the alternator. Lots of vibration at the alt.

Then yeah, just raise the RPM just 100 RPM and it's all smooth as , well, normal.

Yes it's on my S10. Next spring, I will pump it down and install a VOV and a solenoid. Can't hurt.

BTW, I put a Blue orifice in it at the advice of the guy I bought all my parts from. I wonder if that was a good idea now?? He advised against a VOV????

 

If you bought a rebuilt from Autozone, there is a good possibility it is junk. Bring it back an get another. Dont add anymore refrigerant as your pressures are already too high. We seldome use rebuilts, I would rather get one from the bone yard. If we do use rebuilts we use SPI.

 

Blue is the wrong orifice. I maintain a taxi fleet, and I've put VOVs in ALL of them, THEY WORK, :thumbup:

 

You mention that everything was replaced back in 2007? Does that include the condenser as well? Reason why I ask is because metal fragments from a previously bad compressor could be in the system and effecting the new compressor. Secondly, who made the compressor that you installed? I have found out through experience that good ac parts are very hard to find and try to stick to oe as much as possible. As I type, I'm taking a break from installing a new compressor in my 96 mercury. It went after 150K. Since I'm supplying the labor, everything in the system is being replaced with OE equipment. It might cost more but I know its an exact fit and a quality part. FOUR SEASONS petrifies me.

So you mean the condenser might be the source of the problem? I am on the same situation and planning to buy 4 season's condenser. Thanks for this tip. By the way do you mind to share some good compressor?. :welcome:

 

Like I said, metal fragments from a fried compressor are known to linger in the condensor. I've removed condensers and actually have seen the stuff come flying out when we pressurized it. You can tell a lot bu how much crap is sitting in a condensor or an evaporator.

AsIsaidbefore, try to stay with original equipment when purchasing parts. I've had terrible luck with aftermarket stuff.

BTW - the AC in my 1996 Mercury isstill coming out ice cold. That job was done in August.

 

So you mean the condenser might be the source of the problem? I am on the same situation and planning to buy 4 seasons condenser. Thanks for this tip. By the way do you mind to share some good compressor?. :welcome:

I just have my new condenser, my father gave it to me as a gift earlier. Thanks coodeville for the tips about condenser. Big help.

 

My AC compressor makes a fairly loud rumble noise at idle speed in gear. I checked the pressures and it had 25PSI low, 250 high side. Cools very well and is smooth as silk above idle 1200+RPM. Idle speed is about 1100. With AC on and in gear, it's about 950-1000RPM. The whole front of the engine makes this grinding noise like it's got a bad bearing somewhere.

It has a serpentine belt.

I added 12oz. of 134A and brought the pressures to 35 low and 300 high. The noise is better (different), not as loud and seems more of a fast vibration.

Still cools well. Does anyone think I'm still a little low on gas? The system was completely rebuilt in the early summer of 2007. Everything new except the evaporator.

Given the ambient temp in illinois lately I would say you put in 12 ounces too much r 134. The pressures were even a little high on the high side for the ambient temp, whch leads me to think you have the wrong orifice tube as the high side should be a lower especially at 25 degrees outside.
The noise is a rattly reed plate in the compressor. It may have been heated up or hydrolocked when last charged and that can take some of the flex out of them so they rattle,So can the effect of age.
rev the motor for a minute or so to get good pressure going.Then let the engine idle and watch the low side gauge it should stay pretty low close to where it was. If the low side climbs more than Say about 20 percent then either the compressor is weak or the reed plate is not too healthy.Which means you need a compressor.
Some of the guys like to use a variable orifice tube in there ccot systems, I have seen them but cant say I have seen good results, only because i dont use them. They are about 20 bucks or so.
If you have added any oil it to the system you should realize that too much oil raises the pressure in the system as it takes up space designated by design for the freon, and oil doesnt cool you of, freon does.A brand new empty system only uses about 6-7 ounces maybe a little more for a large car for the ntire system. so if you dump in a six ounce can on a used system without changing any aprts you have an overfull system and it wont cool in an extreme temp situation.

 

Given the ambient temp in illinois lately I would say you put in 12 ounces too much r 134. The pressures were even a little high on the high side for the ambient temp, whch leads me to think you have the wrong orifice tube as the high side should be a lower especially at 25 degrees outside.
The noise is a rattly reed plate in the compressor. It may have been heated up or hydrolocked when last charged and that can take some of the flex out of them so they rattle,So can the effect of age.
rev the motor for a minute or so to get good pressure going.Then let the engine idle and watch the low side gauge it should stay pretty low close to where it was. If the low side climbs more than Say about 20 percent then either the compressor is weak or the reed plate is not too healthy.Which means you need a compressor.
Some of the guys like to use a variable orifice tube in there ccot systems, I have seen them but cant say I have seen good results, only because i dont use them. They are about 20 bucks or so.
If you have added any oil it to the system you should realize that too much oil raises the pressure in the system as it takes up space designated by design for the freon, and oil doesnt cool you of, freon does.A brand new empty system only uses about 6-7 ounces maybe a little more for a large car for the ntire system. so if you dump in a six ounce can on a used system without changing any aprts you have an overfull system and it wont cool in an extreme temp situation.

This coming spring I will address the AC system again. I plan to remove the blue orifice tube and go to the proper tube which I think is white, don't remember for sure. Several people have suggested a VOV and I've had as many like you that don't like or recommend them.

I put the system in service and I know there is the correct amount of oil in it as everything was new except for the evaporator and I flushed it thoroughly.

It cools very well but make the growling noise at very low idle. I also plan to install a throttle solenoid to maintain a faster idle with the AC on. Thanks for the advice.