Freon Leak or new evaporator?

[majdoob]

Guys, I've searched the board and read the numerous threads on this topic, but can't seem to find the info that I need. Here is the issue with my 91 NSX...

A few weeks ago, my AC wasn't blowing cold (actually I had the same problem stated by someone in a previous thread where the left side of the center vent blew warmer than the right side of the center vent).

I took it by my local shop and they said I was low on Freon so they added some to the system. This procedure brought my A/C to about 90% of normal.

I let the car sit for about two weeks (only drove it short trips and didn't use the A/C), but when I tried to use the A/C yesterday, it was not blowing cold again!

How would I know if this is because of the cursed problem with the 91-92 evaporator or if I have a leak somewhere in the system and just need to have that corrected, add more freon and then I'm good to go?

Also, if it is the evaporator that is the problem:

Is buying a used one (I saw one for sale from another 91 on this board) ok or do I need to buy a new one from Acura? In other words is the problem with the orginal 91 evaporator or is the problem with the set up of the 91-92 cars? I don't want to buy someone else's 91 evaporator if the problem is with the part itself...I like to gamble, but not on things like this.

I welcome your advice. Thanks in advance.

 

[Acura NsX Pilot]

I think that before you buy anything you should find the source of the problem. On your last visit when they added freon did they also add a dye into the system ? If yes then you need to find where the leak is and then proceed from there.

 

[Daedalus]

I haven't read an evap thread in a while, but I thought the cursed problem with the evaporator was with it leaking.
Assuming the evap is the problem...a new evaporator will probably last longer than a used one that has been in service, but unless it was redesigned, it will be just as prone to failure over time as the original. The '93 AC system was redesigned, primarily for the switch in refrigerants...the '93 has different part numbers for both expansion valve and evaporator. The '93 evap may still "bolt up" and work with the '91 system, but better to know for sure before spending the money.

 

[drew]

First you actually need to do some leak testing. The system will leak at many points and the NSX A/C system is very long.

The evaporator is kinda poorly designed and was probably poorly implemented. They may have fixed the implementation as there seems to be less problems, but the current design is still the same as it was in 1991.

A used evap is as good as scrap.

It takes ~16 hours to replace the evap, you don't want to do the job again for as long as possible. Add in evacuation and recharge and you have a 20 hour job.

The job IS a real pain, a lot of parts and is real easy half-ass it (for that reason alone I would not have anybody else do the work except myself)

 

[davidf]

You need to have some dye added if possible. This will also help locate the leak along with the sniffer. If you have accsess to R12 I would seriously consider not retrofitting. R12 cools better than 134 and at a lower pressure.

 

[drew]

I prefer to use the sniffer first....the modern ones work pretty darn good and you can use them "blind".

Dye gets everywhere after you work on the car making follow-up fairly difficult.

Considering the evap repair is some $3K...it is well worth to buy all the tools and do it yourself. Even expensive tools pay off on the first use on jobs like this.

 

[nsx20014me]

Drew,
do you have a source for a good sniffer. I have this same problem as the OP and I know the repairs can be $$$. My condensor and evap have been replace but I still have a leak somewhere. I would like to learn how to DIY AC evac and recharge and track down the leak. does anyone have a written guide on how to do this?

 

[KooLaid]

Yep, leak. It could be ANYWHERE in the system. That's alot to check. If you were closer I could use our electronic detector to sniff it out.

As a matter of fact, ANY A/C repair guy automotive or home, refridgerator and freezer repair guy should have one.

Common leak is in the soft hose running from the compressor to the hardlines. If the black soft hose is covered in oil/dirt it's probably there.

 

[wilsonp]

I saw a lot of quotes that repair is $3k - my dealer is charging $1350 to replace evaporator after confirming that was the leak (lost freon in 1.5 days). Also includes new expansion valve.

Has it gone down in price lately? Or is this just a great deal (seemed good to me when they quoted it!)

...
Considering the evap repair is some $3K...it is well worth to buy all the tools and do it yourself. Even expensive tools pay off on the first use on jobs like this.