is it unreasonable to ask for a specific test?

ACUser123 on Tue December 06, 2011 12:20 AM

Year: 1998
Make: toyota
Model: corolla
Engine Size: 1.8
Refrigerant Type: 134a

i'm looking for a service shop that will perform an evaporator vacuum test; i'm not sure if this request is unreasonable?

i've taken my vehicle to numerous shops; all of them say the whole system has to be replaced because they cannot find where the leak is. when the system is filled w/134a the ac will stay charged for about 5 days.

so yeah - is it sooo unreasonable? are there tools available that I can perform a vacuum test myself?

mk378 on Tue December 06, 2011 12:46 AM

A leak that large can be found. Some things leak only under pressure, so vacuum isn't the best way to find them. Have you been running UV dye in it? Look for dye at the drain tube. Also it may have a compressor relief valve, those can leak intermittently. If it's a steady leak, an electronic leak detector will pick it up. I think that car is still from the era of Japanese cars where (with the system empty) the evaporator box can be readily removed through the glove compartment without taking the whole dash apart. Do that and look for dye on the evaporator and other parts in the box.

Dougflas on Tue December 06, 2011 7:48 AM

Never had a vehicle that I couldn't find the leak. With due diligence, the different types of leak detectors will find it. Sometimes you'll need dye, electronic, ultrasonic, or refrigerent with N2 but they can be found. Did you try the shower cap over the compressor yet? If you must, remove the evap, seal one end with a blocking fitting, and fit a fitting on the other end. Pressurize it and place it in a large bucket. Look for bubbles after cleaning the evap with evap cleaner. As mentioned, dye will help but use a quality dye that will not easily wash off. Look at the drain tube area. Look for oily deposits. A warm engine compartment will help. Pulling a vacuum is not a very good way to find leaks as systems leak with refrigerent in them. If you do use a vacuum method, you'll surely need a micron guage to get an accurate indication. Some leaks are a bear to find and may take time. I had one that took a month to track down; was a compressor casting that was porus.

Cussboy on Thu December 08, 2011 2:05 PM

Quote
Originally posted by: Dougflas
Never had a vehicle that I couldn't find the leak. With due diligence, the different types of leak detectors will find it. Sometimes you'll need dye, electronic, ultrasonic, or refrigerent with N2 but they can be found.

Also: soap bubbles test.

HECAT on Thu December 08, 2011 2:38 PM

Quote "i'm looking for a service shop that will perform an evaporator vacuum test; i'm not sure if this request is unreasonable?"

It may be unreasonable as a reputable repair shop will want to do the entire job; i.e. find the leak, fix it, and guarantee their work. A positive verification of a leak or no leak in the evap may require much more than just the vacuum decay test; as the other answers have pointed out.

Quote "i've taken my vehicle to numerous shops; all of them say the whole system has to be replaced because they cannot find where the leak is. when the system is filled w/134a the ac will stay charged for about 5 days."

A reputable shop will guarantee their work; I don't think you have been to one of those yet.

Quote "so yeah - is it sooo unreasonable? are there tools available that I can perform a vacuum test myself?"

You would need a set of gauges, a vacuum pump, and something to connect to your evap like one of these.

Edit: Double http Karl.
Thanks

-------------------------

HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdfÃÂ

Edited: Thu December 08, 2011 at 4:04 PM by HECAT

NickD on Fri December 09, 2011 7:57 AM

Ha, my kid took his car to a dealer to get some suspension work done, said it was too stressful, but we got through it. Quote was over 900 bucks, we got the parts for under 200 bucks and did it ourselves in a couple of hours. Wasn't nearly as bad as the rears.

Same with AC, for around 600 bucks can replace everything with new depending on the vehicle of course. These older Corolla's are easy, see Tim for parts. Can't count the folks that came here spending over 2,000 bucks and their AC still doesn't work.

Oh, that era of Toyota was noted for evaporator leaks, all started when the Japanese devaluated the US buck and still tried to remain competitive.

Edited: Fri December 09, 2011 at 8:00 AM by NickD