Expansion Valve Residue?? A/C Issues

Buffjamr · 01-09-2006, 09:42 AM

Is this what a normal expansion valve is supposed to look like?

I'm having some A/C issues and this doesn't look normal to me.

'89 Carrera 3.2 Factory A/C

Recharged 1yr/900 miles ago. Just started blowing warm air. It was blowing cold 3 weeks ago.

I think it's in there somewhere.

cmonref · 01-09-2006, 10:06 AM

Nothiing unusual there. That black "residue" is applied for insulation of the parts that measure and compare temperatures and pressures, thereby controlling the valve.

Brian

Seeeu911 · Seeeu911's Garage

It looks normal from the outside. They do stick but you will need some testing to tell, strange pressure and temp differentials in the system are a symptom.
The gunky stuff is normal, its an insulating tape to shield the valve from enviromentals.
If your system was working I would first check fuses to check that the ac compressor is running when switched on. You can have the deck lid open with ac off then have a helper turn on the ac switch to see if the compressor clutch activates, starts spinning when the switch is on. It is an electro magnetic clutch.

You could also have a refrigerant leak best diagnosed by an ac shop. If you are ready for fun challenge there are many many threads here on DIY AC work. Be very careful as there are significant pressures in the system that can maim or cause real hurt.

Buffjamr · 01-09-2006, 01:46 PM

I was mainly concerned about the black stuff. I guess I'll take it in and have it checked. HVAC is not my strong suit as far as DIY.

Thanks for the help.

Kemo · 01-09-2006, 02:14 PM

since you are so close... check out www.Rennaire.com . The shop is located in Canyon Lake about 35 miles north of San Antonio.

Seeeu911 · Seeeu911's Garage

Quote:

Originally posted by Kemo
since you are so close... check out www.Rennaire.com . The shop is located in Canyon Lake about 35 miles north of San Antonio.

Ron at Rennaire is a Porsche AC guru and a standup guy. You are in most excellent hands with him.

Buffjamr · 01-09-2006, 03:52 PM

Did not know that. I will definitely have them check it out. Thanks for the tip. A good excuse to drive up to Canyon Lake anyway.

griffithstech · 01-09-2006, 06:22 PM

buff,

actually the black insulation tape as you see it is a little overkill.

what needs to be "insulated" is the capillary tube pigtail secured to the top of the oulet of the evaporator (larger tube toward the bottom with the hex nut fitting on it).

if you were to remove all the black insulation tape, except for the portion covering the "pigtail" clipped to the top of the evaporator, the expansion valve would function just the same.

there portions in the evaporator box, such as where the evaporator outlet tube exits the box and where the expansion valve header tube exits (what the valve is attached to) which could allow outside air to enter the box, typically these are plugged with the black tape material.

many 911's have the overkill as pictured and it does not make a difference except to be an annoyance when you need to check for leaks, verify temperatures at the outlet for superheat calculations or replace the valve, should you need to do any of these procedures simply discard the excess tape except where as mentioned above.

otherwise don't worry about, you don't need ac in San Antonio; just drive faster with the top down