Have spent many days over the past several months doing seaches on noise and A/C. Nothing fit the bizzare noise associated with my A/C. So I figure it might be helpful if I shared what I learned in case someone comes up against the same problem.

Preamble: I put in an untested junk yard A/C compressor for a '90 vert that had 65K on the odometer. Brought it to Mazda to have it pressure checked and charged with R12.

About one week later it began making a very weird deep metalic like trombone sounding vibrations on the passenger side. It resonated equally loud both inside and outside the car. For the life of me I could not isolate it. Returned to Mazda.. not a clue. Brought to a A/C specialty shop.. not a clue. The sight window on the top of the reciever showed full fluid and no apparent air bubbles during several compressor cycles.

It generaly only happend with the compressor clutch engaged and when slowing to a stop or at idle. But damn was it loud! Since I had also just tested by BAC and it is out of spec I thought it might have something to with it since the BAC had to kick in as it should at low RPM with the A/C on. But for the life of me could not figured a direct cause and effect.

Today I had a discussion at my house with a guy I had just met who is now a Kia mechanic. Grad of a college based 2 year program. Started the car and he was also mystified at the origin since it seemed to go from the reciever thro all the alum tubing back inside the car. Sight glass still full and no air.

We take a stab in the dark and begin to carefully and slowly bleed the reciever using the 8 mm bolt on the top. After doing so intermittently for about 5 minutes, holly crap the noise stopped and is apparently fixed. Seems there may have been many many tiny air bubbles introduced in the filling and the Mazda folks did not carefully bleed the system after the fill.

I quess my lesson is to use the reciever glass with a grain if salt. I regret the long post but I had not been able to find this problem described on this or any other RX7 forum and hope it helps those like me who are really marginal on A/C problems.

 

Have spent many days over the past several months doing searches on noise and A/C. Nothing fit the bizarre noise associated with my A/C. So I figure it might be helpful if I shared what I learned in case someone comes up against the same problem.

Preamble: I put in an untested junk yard A/C compressor for a '90 vert that had 65K on the odometer. Brought it to Mazda to have it pressure checked and charged with R12.

About one week later it began making a very weird deep metallic like loud trombone sounding vibrations on the passenger side. It resonated equally loud both inside and outside the car. For the life of me I could not isolate it. Returned to Mazda.. not a clue. Brought to a A/C specialty shop.. not a clue. The sight window on the top of the receiver showed full fluid and no apparent air bubbles during several compressor cycles.

It only happened with the compressor clutch engaged and when slowing to a stop or at idle. But damn was it loud! Since I had also just tested by BAC and it is out of spec I thought it might have something to with it since the BAC had to kick in as it should at low RPM with the A/C on. But for the life of me could not figure a direct cause and effect.

Today I had a discussion at my house with a guy I had just met who is now a Kia mechanic. Grad of a college based 2 year program. Started the car and he was also mystified at the origin since it seemed to go from the receiver thro all the alum tubing back inside the car. Sight glass still full and no air.

We take a stab in the dark and begin to carefully and slowly bleed the receiver using the 8 mm bolt on the top. After doing so intermittently for about 5 minutes, holly crap the noise stopped and is apparently fixed. Seems there may have been many, many tiny air bubbles introduced in the filling and the Mazda folks did not carefully bleed the system after the fill.

I guess my lesson is to use the receiver glass with a grain if salt. I regret the long post but I had not been able to find this problem described on this or any other RX7 forum and hope it helps those like me who are really marginal on A/C problems.

 

 

Venting that air condition stuff in our air huh tough guy!! HEHE

 

I honestly had the same concern. However, there was very little vapor and as I indicated it was carefully and slowly vented. Not much choice since two trips to shops which should have been competent could not diagnose the problem.

I hereby pledge to make amends for the freon dump by reducing my contribution to atmospheric CO and methane by smoking one les cig. a day and absorbing rather than releasing one flatus burst a week.

 

Classic

 

Wow, the Mazda dealer had actual R12?
I'm suprised it's still available.

I'm curious - what's todays price for R12?

 

Total cost for test and fill was $157.00. The freon was $80.00 of that total.

 

why don u just take out ur ac its pointless if u want a modded car

 

Because not everyone wants to sacrifice comfort and convenience to shave a 100th of a second off their quarter mile for the whopping 30 pounds of weight saving.

You wanna save weight? Get on the treadmill. There's nothing uglier than a street driven car with an interior that the owner butchered, and converted everything to manual

See how cool you are when your girl's mascara is running down her face cuz you wanted to shave a couple pounds of A/C weight hahah

 

I'm with Fingers on that.

I'm removing my A/C just because I don't use it. Not to gain any speed. It's actually to save room so I can access my spark plugs better.

The weight you lose from removing it is gained back by that cheeseburger and crazyfries you shouldn't have ate.

 

Yeah that's acceptable... but i'm sure my city's not alone with 800 civic drivers with competely stripped interiors, owners sitting on plywood, just to conserve weight lol

 

I am in the upper 3% in the age poll. Have drained my gene pool, sun roof ain't working and sweat glands are hyper active. Since this old fart has no desire to street or legal race, I am keeping my beauty pristine, original, and cool in the summer.