A/C problem
 

I live in Abilene and i drive home every weekend to sort out a few things.

This past monday i had my mom take my FD to one of the only a/c shops that still work with R12 systems, as my FD is a 93.

They found that there was only 4oz of R12 remaining, they pulled a vacuum, found no leaks and filled with proper amount of R12.

As my mom drove it home she called me on my lunch break and had said the a/c is working perfectly, ice cold.

She parked the car for the rest of the week until friday where she was taking it to the body shop to get a cost estimate of the damage that was left by a drunk driver last weekend. (Dont worry, no dents oddly enough, just a lot of paint transfer, deep scratches and a broken driver side mirror)

She calls me on her way to drop the car off and says that the a/c is not blowing cold at all.

Any thoughts as to what it could be?


She is taking it back to the shop where they worked on it, but wondering what you guys who fixed your FD's a/c system have to say

Is the compressor cycling at all?

saying there are no leaks under vacuum is kind of pointless. the system sees 30-275 psi, so checking it under vacuum (~15psi)...

if it was low on refrigerent it has a leak period

You mean is the clutch engaging and disengaging? If thats what you mean then no, the compressor is constantly engaged

You let your mom drive your FD? Lol, my mom can barely get in to and out of my car.

so when you turn the a/c switch off its still engaged?
try turning your a/c off then turning on your car...then if its still engaged your switch or somewhere in the wiring is jacked up. or your thermostat(climate control) could be jacked up

No no no.

The compressor is not engaged when the a/c is switched off, it free wheels as its supposed to.

Im saying is that when its switched on the compressor is engaged all the time.

But either way i'll try that.

As for the climate control, when i switch it from max cold to max hot, the temp changes as supposed to..... gets blazing hot. When switching back from max hot to max cold and turning a/c switch on, i can hear and see the compressor kick on, yet the temp doesnt change much, just gets a few degrees cooler than max hot.


Either way, the car is going back to the shop as its under warranty. If its not fixed then its going to Auto Specialists out in Round Rock or Georgetown. My buddy Oun told me TexasRX's club have their FD's worked on there for maintenance and road race setup so i'll give them a shot.

You are going the right road by having the shop have another look at it. I fought a similar thing on my B2000 years ago, leak-down tests and vacuum tests kept showing the system was 'fine', yet it would lose its refrigerant in a matter of days.
FINALLY did the ultraviolet test using dye and a black light to find there was one little friggin' O-ring leaking by a connection to the condenser. Fixed that and have been happy ever since.

An electronic leak sniffer should be able to find a leak that big. Also, it would be a good idea to have them replace the drier while they have the system apart. You can get driers for the Nippondenso system for $15 or so.

My mom called and updated me.

They ran the electronic sniffer test.

Theres a hole in one of the lines, and a leak from the compressor.

Looks like i'll be searching the forums for a good used a/c system.

Check around and see if you can find somebody to patch up the line. They need to have experience fixing aluminum A/C lines.

I, personally, would not get a used compressor. You're just BEGGING for trouble. If it fails, it will spew a bunch of metal debris into the condenser, and then you'll need a new condenser....the parallel flow condensers that these cars use are VERY difficult to get clean after they're contaminated.

Did they say where the compressor is leaking? Mine had a shaft seal leak from long periods of inactivity, and I put some extra oil in the system, replaced the drier and recharged it, and that appears to have re-lubed the seal and stopped leaking. If my car is still leaking, the leak is now dramatically smaller.

The leak is big enough on both the line and compressor that only about 8oz is left.


I dont know which compressor the FD takes, what should i look for to find out if i have the MANA or Nippondenso?

The FD uses what's known as a Nippondenso TV14C compressor. As far as I can tell, the same compressor is used for both the MANA and Nippondenso cars even though Mazda lists two different part numbers. It is a rather odd little critter that wasn't used in too many cars.

To determine which system you have, look at the reciever/drier & sightglass:

If the sightglass is in the block fitting bolted directly to the top of the drier, then you have a Nippondenso system. Also, the drier body itself should be silver in color, and flat on top, but the color is not a hard and fast rule.

If the sightglass is in a little cube in a line attached to, but not directly on top of the drier, then you have a MANA system. The drier body is typically black in color, but the only aftermarket replacements available now are silver.

It depends (I think) on whether you have the touring model or any other model. Call Ray Crowe at Malloy Mazda. If parts are available, he will find them -- and charge much less than any other Mazda dealer.

Touring = Nippondenso appears to be true for 1993 MY cars, but after that there seems to be no rhyme or reason.

If you have a hole and you drove with the hole and system ON, you must assume contamination, and a loss of oil as well as refrigerant.

Get a new hose. Replace both HIGH and LOW valves (go to NAPA for the proper valves). FLUSH SYSTEM and purge with nitrogen.

Install a new receiver/dryer along with your new compressor. Make sure to add the proper amount and type of oil. Hopefully your new compressor has NO oil. Otherwise, find out what's in it. If you're running R12, it's mineral oil. Typically you add oil to both the compressor and receiver/dryer if they are new/not filled, and/or flushed. The service manual has the quantities.

If you can't afford R12, use Envirosafe IS-12, but add R134a adapter fittings to HIGH and LOW (still run mineral oil) to keep it legal, and document the system as such.

DO NOT RUN R134a, it just doesn't cool enough for a system designed for R12.

Do a seach here on Envirosafe for more info.

:-) neil
hot & humid Florida

Actually, it isn't. I know the shop manual says mineral oil, but all the TV series documentation from Nippondenso and Toyota and even the compressors themselves say otherwise. Nippondenso actually used some sort of synthetic known as ND-7 in R-12 applications, and ND-9 in R-134a applications. ND-6 is mineral oil.

My guess is that ND-7 and ND-9 are DEC PAGs in different viscosities. It doesn't smell like mineral oil, and it seems to decompose like a PAG/POE when exposed to moisture.

JM1, I would be surprised if its PAG/PAO as they are not compatible with Chlorinated refrigerants, i.e., CFC's such as R12.

What is compatible with both mineral & synthetic oils and is safe to use in either case is Ester oil; if in doubt as to what's in your system, just use ester.

I have added heavy mineral oil to these systems (sus525, iirc) and have not had any problems with it over the last 10 or years so (other than small compressor shaft seal leaks).

DEC PAGs are compatible with R-12.

http://www.pag-idemitsu-usa.com/pag_pr.htm