A/C blows cold up until it hits 80 degrees outside...

[dude8383]

My a/c unit blows cold at temperatures below 80 degrees F. Now once the temperature goes any higher, it just starts blowing warm air.

I have a feeling its the A/C Drier where the pressure switch is located.

Do you guys think its the pressure switch thats making my a/c run like crap??

Here are the parts that I'm talking about...

Drying Container - 64 53 8 391 025

Safety Pressure Switch - 64 53 8 390 971

Plug Terminal - 61 13 1 378 400

Any suggestions would be greatly appreciated!

[lordofthewaters]

Sounds like an expansion valve to me.

[dude8383]

Sounds like an expansion valve to me.

Is it the same thing as a pressure switch?

Or are these two completely different?

[lordofthewaters]

Completely different animals.

expansion valve in diagram

BMA has them for $18.18

[m42technic]

Is your system fully charged?

[dude8383]

Completely different animals.

expansion valve in diagram

BMA has them for $18.18

Hmm, that doesn't look like its going to be fun to replace.

I'm going to check if the system is fully charged before doing anything.

This will be my first place to look though!

Thanks

Is your system fully charged?

I'm going to be checking this at the end of the week.

:)

[lordofthewaters]

Well I was taking for granted that you'd already checked the refrigerant. 8)
So yeah, that's always the first thing you should check. If it's low check for breaks loose connections, and refill. Then move on. I've seen and heard of these exact symptoms being the expansion valve though, so that's the first thing that comes to my mind.........

[dude8383]

Well I was taking for granted that you'd already checked the refrigerant. 8)
So yeah, that's always the first thing you should check. If it's low check for breaks loose connections, and refill. Then move on. I've seen and heard of these exact symptoms being the expansion valve though, so that's the first thing that comes to my mind.........

Hehe, well I couldn't find my gauge to check the pressure. My friend has had it for the past couple of months so I completely forgot about it.

I gotta pick up the damn thing...

But thanks man, I'll keep the thread up to date.

[CorvallisBMW]

I had exactly the same probelm, here was the fix:
Low pressure caused by too little R-12 caused the low pressure switch on the reciever/drier to trip. For some reason, it only became a problem on days above 75 F or so. I filled it up with another 1.5 lbs of R-12 and boom! worked perfect. Even though the sticker on my car says 2.15 lbs of refrigerant, I had to put in about 2.75 lbs before it worked properly.

[dude8383]

I had exactly the same probelm, here was the fix:
Low pressure caused by too little R-12 caused the low pressure switch on the reciever/drier to trip. For some reason, it only became a problem on days above 75 F or so. I filled it up with another 1.5 lbs of R-12 and boom! worked perfect. Even though the sticker on my car says 2.15 lbs of refrigerant, I had to put in about 2.75 lbs before it worked properly.

Hmm interesting..

I'm going to have to add some more R134a then. I'll pick up my pressure gauge tonight.