Expansion block

88 Wagonman

New member
I know I know, you guys are as tired of A\C questions as much as lift\tire questions, but here we go. In an effort to find out why the A\C in my 88 does not work as well as my 91 I have been comparing the two to see what differences there are. Both have been converted to r134, Both read about the same pressures, blend door, blower, all that stuff is fine, e-fan, clean condensor, etc. The only difference I could find (other than the obvious differences from renix to HO) is that the expansion block on the 88 is rotated 180 degrees from the way the 91 is. I have had the block off 3 years ago to do the heater core and I wonder if it is possible that I may have switched them around? I have an old evaperator lying around and it looks like the fittings are the same. Obviously the high and low pressure hoses will only fit one way due to the different fittings, but would this cause any reduction in efficiency?

91



88
 

88 Wagonman

New member
I was only able to check my low side today, I need a new o-ring for my high side fitting. At idle it was about 35 and at 1500 rpm about 26. Same for both jeeps. At the beginning of the summer I pulled a vac, added oil, and added the proper amount of r134 as per the chrysler TSB on conversions.
 

Saudade

NAXJA Member
NAXJA Member
What's the temp there today? Checking the weather site, says it's almost 100 there today.

Can you see any bubbles in the sight glass?
 

88 Wagonman

New member
Sorry, forgot about the ambient. At the time it was about 85. I thought that the sight glass became useless after converting the system? To be honest I have never even looked at it.
 

Saudade

NAXJA Member
NAXJA Member
Ah... You may be right about that. Only way to tell for sure is to check the high side pressure.

Can you use a thermometer to check the outlet temp?
 

88 Wagonman

New member
I will get a thermometer tomorrow and check. Another thing I thought about is the fan speed. In the 91 it is still the stock speed (fairly slow even on high) and on the 88 I have wired in a relay on the high speed circuit to give 12 volts to the blower, thus making it move a lot more air. Could I be blowing too much air and my A\C can't keep up?
 

Saudade

NAXJA Member
NAXJA Member
Hard to say. Certainly possible. But if it's on MAX, then you're recirculating the cooled air inside so it may take a while to fully cool down.

I know mine is a bit low but I have about 45-46 deg at idle (once everything has cooled off) and around 38-40 deg (hard to read those small dials) at 2000rpm. That's at high fan, on MAX, windows up. It's just over 80 here today.

It certainly doesn't feel that cold inside. I have no tint on the windows and it's bright and sunny out. The inside temp was over 110 when I got in it earlier.
 

88 Wagonman

New member
Hard to say. Certainly possible. But if it's on MAX, then you're recirculating the cooled air inside so it may take a while to fully cool down.

I know mine is a bit low but I have about 45-46 deg at idle (once everything has cooled off) and around 38-40 deg (hard to read those small dials) at 2000rpm. That's at high fan, on MAX, windows up. It's just over 80 here today.

It certainly doesn't feel that cold inside. I have no tint on the windows and it's bright and sunny out. The inside temp was over 110 when I got in it earlier.
I measured the temps today on my 88:
Ambient about 95*F
Vent temp at idle fan speed on high: 52*
Vent temp at idle fan speed on 3: 48*
Vent temp at 2000 RPM fan speed on high: 50*
Vent temp at 2000 RPM fan speed on 3: 45*

Today it felt like it was working ok, mainly due to the cloudy sky hiding the sun. I'll try to get the temps from the 91 another day.
 
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