Automotive Air Conditioning Information Forum (Archives)

CFSpit on Tue August 03, 2010 6:44 PM

Year: 1997
Make: Dodge
Model: Grand Caravan
Engine Size: 3.3
Refrigerant Type: r-134
Ambient Temp: 80
Pressure Low: 40
Pressure High: 250
Country of Origin: United States

I just completed replacing parts in my mini-van Including the front evaporator, both condensers the filter drier and the front expansion valve and 48 oz. of new R-134. I have a vac pump...pumped down 3 times and it held vacuum over night..

I have had leaks in the evaporator for a long time, and I ran Sure Seal though the system which I thnk caused other compontents to fail. I have replaced the compressor on several occasions and replaced the main condenser once before after black death on the 1st compressor. I was afraid to pull the dash and get to the evap....finally did it. Took a day and a half... that's a 12 hour day and 6 hours the 2nd day.

Any way it doesn;t seem to me like the air temp at the vents is low enough. The compressor seems to be able to drive up enough pressure. Fans are kicking on @ 250 Psi on the high side.

After fixing it, I took it for a drive, unit set for recirculate..and when it was 76 degrees outside I was getting 38 degree air out of the front vents. Is that good enough?

I was hoping to get even colder air. I think that with everything with the exception of the rear evap and expansion valve being new it would do better? It always seemed like in the past that the rear air performed better than the front.

Could I have a problem with the new expansion valve? Is the expansion valve body supposed to be in solid/direct contact with the plate that loops around the in and out tubes of the evaporator..seems like I have some gap there. Is there anyway to test the expansion valve?

Any comments welcome

CFSpit

TRB on Tue August 03, 2010 7:08 PM

Quote
Originally posted by: CFSpit
I was getting 38 degree air out of the front vents. Is that good enough? CFSpit

Water freezes at 32 degrees. So yes this would be a very good outlet temp.



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jglanham on Wed August 04, 2010 5:03 PM

If your vehicle has a manual system, the temperature probe in the evaporator tells the compressor clutch to switch off at 34 degs., and on at 37 degs. If you have the ATC system, the settings are variable. This keeps the evaporator from icing up. The TXV block mounts to the evaporator with a metal gasket. This is why you are seeing a slight gap. It's normal. A TXV can fail in three different positions - open, closed or restricted. Open will result in a noisy compressor or no cooling. Closed will will result in low suction pressure and no cooling. Restricted will result in low suction pressure and no or poor cooling.

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johnl