r134a retrofit q's

[paanta]

Sorry if this was covered in an FAQ somewhere, but I didn't see much on specific parts required...

My A/C is blowing air hotter than normal outside vent air, so I suppose it's time to recharge/convert the system... BavAuto has an r134a retrofit kit that sells for $180(!!!). It says it includes a receiver dryer, wiring, and new service ports....looks like "wiring" really means a new pressure switch: http://www.bavauto.com/assets/imglib500/82319067396.jpg

$180?! A new receiver dryer costs $37 here: http://www.germanautoparts.com/BMW/1...2/7529/2454440

They've got two pressure switches: http://www.germanautoparts.com/BMW/1...2/7536/2430925
One is $40 and one is $8? Do I need the $40 for the later style receiver dryer? Or can I just reuse my old pressure switch?

I also assume any R134a kit will come with the correct fittings? Is there anything weird about the stock E34 fittings? Anything else I need?

[Blitzkrieg Bob]

$180...wow that's kinda hi for just a dryer, ports and switches.

You could do it for a lot less, especially if you are also trying to diagnose a leak.

To do it right, you’d wanna flush the system, change to compressor oil and put in a new dryer and pressure switch.


If you have a leaky system and need to diagnose the leaks, I’d just convert the ports, evac and recharge with a shot of UV dye to spot the leaks and prepare to replace a bunch of stuff.

[paanta]

I don't know if there's a leak. It's still R-12 (unless the ports weren't converted) and still had lotsa pressure when I depressed the plunger on the schrader valve. I'm not sure why there's no cold air. The compressor seems to kick on properly, but the air gets warmer when I turn on the A/C. Is there something that could cause that other than a lack of refrigerant?

My plan was to
1) "dispose" of the R-12 the cheapest way my liberal college town conscience can deal with, bearing in mind that my 2 yo son will inherit this earth, then
2) use a compressor scavenged from a mini-fridge to evacuate the system,
3) see how she holds a vacuum, then
4) remove the compressor and pour out the old oil
5) swap in a new dryer + whatever and charge 'er up.

So...questions:
1) Is there a dye kit/UV light that's reasonably price? That just seems like such pro-shop sort of equipment. :)
2) What switch do I use? Can I reuse my switch? I posted a link to two switches...one was $8 and the other $40?

I appreciate the help. Air conditioning is such a miserable black box to me, in spite of all those thermodynamics classes back in college. :)

[Scott C]

Have you ruled out that the heater core is NOT putting out heat with AC on?

Scott

[paanta]

It's not putting heat out when the dual zone things are set to full cold...I just get nice cold vent air. When I turn on the A/C the temperature goes up. I assume that means the valves are working?

[Blitzkrieg Bob]

It's not putting heat out when the dual zone things are set to full cold...I just get nice cold vent air. When I turn on the A/C the temperature goes up. I assume that means the valves are working?

You might want to check to make sure you expansion valve is operating.

do you have a gauge set and manifold for A/C?

Check down below the glovebox and try to feel the exchanger to see if it is actually cooling.

[paanta]

You might want to check to make sure you expansion valve is operating.

do you have a gauge set and manifold for A/C?

Check down below the glovebox and try to feel the exchanger to see if it is actually cooling.

How do you check to see if the expansion valve is operating? Or should I just read the damn Bentley. :)

[whiskychaser]

You might find this of interest:
http://gator482.hostgator.com/~bruno/Wiki/tiki-index.php?page=AC+upgrade
Pretty sure you need a different pressure switch and the article mentions it. If you find a source for the kit thats nice and cheap be sure to post it. I should have done this ages ago:D The BMW retrofit kit was about £120 last time I asked but like I said that was some while ago