I recently studied up on A/C's and how they work and how to repair/charge them. I went and bought all the necessary equipment for the job. I successfully changed out the evaporator on my '06 BMW so I'm feeling somewhat confident and want to try it out on the suburban but I have a few questions I need answered:

1) On my suburban, the first thing I see after the compressor is the expansion valve. I know this because on one side it's hot and on the other it's cold. After that it goes to a large silver cylinder. Is this the dryer? I'm not sure what this is.

2) Are there any tricks to filling it up after a full vacuum? I ask this in the context of the rear A/C unit. I assume this has no bearing on filling the system, it's just open the can and fill it was the proper amount of coolant, correct?

3) Anybody on hear ever hear of a parallel flow condenser? Apparently it's much more efficient on a R134 system. Do they come with these from the factory or would it have to be retrofitted?

 

You really should have some one who knows exactly what they are doing do this job. The expansion valve is AFTER the Condenser. The Large cylinder is the accumulator/filter/dryer and the small silver device right before the compressor should be a muffler.

 

You're correct. I meant to say condensor.

 

I think that the capacities for the AC system are listed in the owners manual under the capacities...I don't have manual in front of me at the moment so I won't swear to it....

 

If the system was open to the atmosphere for any length of time, it will need to be evacuated for a very long time to dry out the dryer or the dryer will need to be replaced.

Capacities are usually listed on a decal under the hood.

 

It's never been opened up and there is technically nothing wrong with it besides the fact that it doesn't seem to be quite as cold as it should be sometimes. My wife says it seems to come and go a bit which make me lean toward the expansion valve.
I'm just trying to gain an understanding of the system on this as it has a rear air. What it looks like to me is that after the condenser, you have the expansion valve (I'm doing this from memory at the moment) and from there it feeds the dryer. The dryer splits off with one line going to the dash and the other to the rear air.
Do I have that correct?

 

The txv is for the rear only. The front set expansion point is all the front ac uses. If it comes and goes with temp, then you are low on R134A and have a leak.