AC expansion valve in a B4

OK, I've searched and tried to find this, but where, physically, on the car is the expansion valve (capillary valve) on the AC on a 1996 B4? I have a system where the compressor is engaging, definitely has pressure in the lines, and the compressor is working, but produces no cold air nor any temp differential on the high/low tubes under the hood.

From longtime past experience, I am immediately suspicious of a clogged expansion valve.

Problem is, without lighting up the virtual machine so I can load my Windows-98-only Bentley CD, I can't find the thing. Where should I be looking? On my classic Saab 900s, it was under the hood. On my 240 Volvos, it was above the passenger's feet in the cabin.

Suggestions for hunting it down would be welcome. Yes, I have the 134a fittings and a lab-grade vacuum pump. Just need to find the spritz valve.

The high and low side ports are on the lines, near where the duck under the cowling, heading towards the right side firewall. There, just before the lines pass thru the firewall is a black plastic rectangle. The black plastic rectangle is an insulation cover for the TXV.

Tony

Sounds like the control valve in the compressor. Need to put some gauges on it.

Control valve?

klxd said:

sounds like the control valve in the compressor. Need to put some gauges on it.

Click to expand...

so how can one tell the difference between a bad txV and control valve problems??

Bad control valve can cause little or no pressure increase by the pump.

A plugged expansion valve will cause the high side to be too high and the low to be too low.

So, you need gauges to diagnose.

If you're in the system, go ahead and replace the compressor,exp valve and dryer. It will cost you a little more for the dryer and valve. If I recall, they're under 100 bucks-the compressor is the only big ticket but in the long run,if you plan on keeping it,money well spent. Make sure you replace all the orings too. They come with the components. I don't recommend trying to isolate one component because you're wasting expensive freon to fill and check. The old dryer is probably full of crud anyhow. When you do get the components on,make sure you vacuum the system down prior to filling. Of course you need gages and a vacuum pump to do all this. You'll have to partially remove the plastic inner fender on the right side to access.

Thanks

I appreciate your input , freon is $8 a can at big lot for whatever it is worth. I'll try once to evacuate and re-fill , if no result i'll do the wholesale swap.

Thanks again for the help
update: no need for re fill , the compressor imploded , i'll go for the package .
any good ideas for the flushing process??

Cheapest parts first

chrisvb said:

so how can one tell the difference between a bad txV and control valve problems??

Click to expand...

I tend to look at the cheapest part that's easiest to replace first. Then again, a set of gauges would be a useful thing to have around.

Thanks for the input, everybody on the location of the valve, I'll slurp the system down and see if it's plugged.

At this point, even a little cold would be extremely helpful. I have another compressor I can swap in, but it's a PITA usually.

chrisvb said:

I appreciate your input , freon is $8 a can at big lot for whatever it is worth. I'll try once to evacuate and re-fill , if no result i'll do the wholesale swap.

Thanks again for the help
update: no need for re fill , the compressor imploded , i'll go for the package .
any good ideas for the flushing process??

Click to expand...

For how many ounces? The B4's capacity is about 41-41.5 oz iirc...

i understand the mk3 takes 1100 grams or about 3 cans

Spec on my core support sticker: 1150grams +/- 50grams

Tony

chrisvb said:

I appreciate your input , freon is $8 a can at big lot for whatever it is worth. I'll try once to evacuate and re-fill , if no result i'll do the wholesale swap.

Thanks again for the help
update: no need for re fill , the compressor imploded , i'll go for the package .
any good ideas for the flushing process??

Click to expand...

I didn't flush mine. Normally if you're replacing the whole lot, it's not necessary. A new dryer will catch any particles trapped and they are usually trapped in the old dryer and compressor too. That's why the compressor mfrs won't warrant a new compressor without replacing the dryer too.