THSCC Forums

The A/C on our 97 Mustang with 100K miles quit yesterday. Initial impression is that the high pressure cutout may be activating which I understand would be due to low refrigerant (134).

The system has NEVER been serviced. It may have been "acting up" in recent weeks.

Is there any point in adding refrigerant using one of the available kits which include gauges? Or would we be better off getting it serviced "properly"?

My concern is that even if the problem is a sloooow leak, is there likelihood of moisture in the system that should be removed?

We intend to keep the car a lot longer so we don't want to do something temporarily that may actually contribute to higher repair bills in the future.

Thanks!

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Dick Rasmussen

FS 50 2018 Mustang GT

I'm not an expert, but I have diagnosed and repairs on several car ACs.

In my opinion, every home wrencher needs one of these:

http://www.harborfreight.com/cpi/ctaf/d ... mber=92649

I check my cars once in a while just to make sure they are close to operating correctly. Many of my older cars lose a little bit of R134a over time.

If your car is a little low but still holding some pressure, no need to worry about moisture. Use the gauges, add R134a to get it up to spec, then see how long it takes to leak out and stop working again. If it lasts another 9 years, all is well

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Mike,

Your idea of "not an expert" is my idea of "might as well be an expert"

With the gauges, do you use the factory shop manual to find the correct specs or are there "generic" pressures to look for? I have the manual for the Mustang(s) but our Dodge van has been converted to R134a and I don't have specs for the conversion in the old shop manual.

Thanks!

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Dick Rasmussen

FS 50 2018 Mustang GT

You can use the FSM, but if you don't have that, usually you can use find the pressure from a model specific forum. I did that with my Volvo and it did the trick. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Mike, your idea of "older" must be different than mine

Converted cars aside, wasn't R134a standard in new cars starting in ~1994??

Bret.

Yup. My 1994 Volvo was 134a from the factory. So was my '95 Protege. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Thanks for the info guys. I won't get a chance to use it this time since Kelly took the car to a local shop we have had good luck with in the past and is sitting in their waiting room while they work on the car. Something about it being too hot to wait any longer before getting A/C again.

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Dick Rasmussen

FS 50 2018 Mustang GT

UPDATE:

Problem was a worn out low pressure (cycling) switch so the system had to be evacuated and recharged. Unfortunately after getting it home and looking under the hood to look at the work I heard a HISS. The o-ring on the pressure switch was either cut or defective so they get to do the work again . . . under warranty of course.

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Dick Rasmussen

FS 50 2018 Mustang GT