Forward Expansion Valve

[joezek]

I have intermittent A/C in the front system and am thinking it's the expansion valve. I fixed the rear system months ago by replacing it's expansion valve. Maybe the front is also broken.

Has anyone messed with the front valve? If so, where is it located? Did you take it apart and clean it?

The rear one that I removed was easy to disassemble but I replaced it anyway since the new one was only $14 as a surplus ebay find.

 

[06EXP]

I thought mine was the expansion valve since mine was also intermittent and that seems to be a common problem. But mine turned out to be a pinhole leak in one of the lines that my mechanic found yesterday. New part was ordered and will be put in tomorrow, but until then we have a full charge on our ac and man is it good to have it back. Almost had icicles forming off my face driving it home from the shop yesterday!

 

[joezek]

Glad you got yours figured out. I ordered a new forward expansion valve from ebay, only $15 new. In the mean time I serviced it again, this time left a vacuum on it for 30 minutes like your supposed to before filling with freon.

Last time I was impatient and only applied vacuum for 10 minutes. Possibly there's moisture freezing up the expansion valve, we'll see.

It's like it gets cold slowly for about 3-5 minutes, then suddenly a burst of very cold air for about 1 minute, then suddenly just barely cool air for about 3-5 minutes. It repeats that cycle over and over.

It had plenty of freon, 3LB came out. So I topped it off once again with exactly 54 ounces.

Once I get the bugs worked out (already fixed rear exp valve and both rear motors) then I'm going to try using R409. I've got a big tank of it at work. R409 is a direct drop in for R12 and it's 20% colder than R12. My a/c guy swears by that stuff, says it's very cold. The only catch is that even though it's certified as a drop in for R12, it's only supposed to be used on appliances. Since I'm privately using it and not commercially filling up peoples cars, I don't care and I'll experiment on my own vehicle.

The R134a is great too, but to me the colder the better.

 

[Racenut]

Glad you got yours figured out. I ordered a new forward expansion valve from ebay, only $15 new. In the mean time I serviced it again, this time left a vacuum on it for 30 minutes like your supposed to before filling with freon.

Last time I was impatient and only applied vacuum for 10 minutes. Possibly there's moisture freezing up the expansion valve, we'll see.

It's like it gets cold slowly for about 3-5 minutes, then suddenly a burst of very cold air for about 1 minute, then suddenly just barely cool air for about 3-5 minutes. It repeats that cycle over and over.

It had plenty of freon, 3LB came out. So I topped it off once again with exactly 54 ounces.

Once I get the bugs worked out (already fixed rear exp valve and both rear motors) then I'm going to try using R409. I've got a big tank of it at work. R409 is a direct drop in for R12 and it's 20% colder than R12. My a/c guy swears by that stuff, says it's very cold. The only catch is that even though it's certified as a drop in for R12, it's only supposed to be used on appliances. Since I'm privately using it and not commercially filling up peoples cars, I don't care and I'll experiment on my own vehicle.

The R134a is great too, but to me the colder the better.

BEFORE you use the R409 you BETTER MAKE SURE THE OILS ARE COMPATIBLE WITH R134A. It is a direct drop in for R12 but R12 and R134A use two different oils that are NOT compatible with each other. You may cause your self problems in the long run. Just do your self a favor and make sure you check if those oils are compatible.

 

[joezek]

Well looks like it's cured and working normal now. I must have had some moisture inside the system and it was all removed during the 30 minute vacuum I had on it yesterday.

When I left work I turned the a/c on as usual, the entire ride home from work there was freezing cold air that only slightly got warmer for a minute, so I lowered the temp control to 60 and right away it was freezing cold again. The rear system stayed ice cold as well.

The other test was during the ride to work when the outside temp is about 15 degrees colder. Normally it froze up and quit working every couple minutes. Today it's fixed and blew ice cold air the whole trip.

It's so cold that I don't think I'll be messing with colder freons. During a 20 minute drive home in city traffic it got so cold that I either needed a jacket or turn down the fan. First time it's done that since I bought the truck.