She puked!

[cphilip]

her AC that is. Very hot here in the SE (over 95 F today) and after a couple days of running my nicely cold AC the last couple days pretty regular.

Today, she decided to puke some fluid/oil out of, what looks like, around that switch that is located right near the Accumulator (not too good on AC parts names so might have that wrong but the canister looking one with the sight glass just near the front bumper on passengers side). Does that itself switch leak sometimes? There is nothing on the lines coming to and from it. All on the switch and some on the accumulator and then the spillage down below it and off onto the ground. Perhaps maybe 10-20cc's of greenish oily fluid (not coolant as too thick and wrong color and smell). Probably has leak test die in it. We charged it a few months back as it was low and we wondered why it was low. Now... I think we know. But it appears sporadic too.


I imagine the system will have to be drained to replace it ether way. Will have it looked at tomorrow anyway and not use it in the mean time in case its lost a significant amount but it was cooling still very well when I parked the car. And I always turn the system off and let the car run a few minutes to cool down the turbo anyway so did the same thing this time. I almost suspect it leaked AFTER I shut off the motor but can't swear to it.

So whats your thoughts? Can that switch itself leak? The switch with two wires running to it. Whats that called? Thought I saw bubbling out of it. Will probably evacuate it and replace and then leak test is probably best plan.

[krwsenior]

Mine did the exact same thing a few days ago. I ordered a new Low Pressure switch from ******** of Arizona. When it arrives, I will replace, evacuate and recharge.

I noticed mine bubbling a while back too. I knew it was coming soon. krw

[dieseldiehard]

Is the system original, that is running on R12? if so leave it that way when you have the switch replaced, do not succumb to any pressure to go to R134A

[cphilip]

Oh sorry about that. Dang me... I meant to add a disclaimer and forgot

The PO changed it to 134a so I am sort of stuck with it. But... it has been running really well for 134a I must say.

[Matt L]

Was the pressure switch replaced for that conversion? If not, it should have been. The stock switch is a low-pressure cutout only, the replace is a binary switch.

[krwsenior]

Originally Posted by Matt L

Was the pressure switch replaced for that conversion? If not, it should have been. The stock switch is a low-pressure cutout only, the replace is a binary switch.

What is a binary switch? There were no options on the website when I ordered a new switch. My car has also already been converted. krw

[cphilip]

You got me Matt... I do not know. He changed many things as they appear new. Particularly hoses and fittings. The Accumulator appears older though . The switch does not really appear that old but I cannot be sure. He had it done. But he had no real records of exactly what was changed and what wasn't changed. When I got the car it was working but just weak. So we charged it (suspecting a leak but never saw one) and it worked without fail from then on but I haven't really used it too much either. But this is the first evidence of any leakage. Fairly suddenly and probably when parked it today I would say.

Added on edit: looking at the online catalog here I see that the Low pressure only switch is more of a metalic Brass colored body and this one on my car appears more Black Plastic so I am going to guess it is a High/low set up like it has been replaced at some time.

I found this parts description on a High/Low switch online just now...

1977-1993 Mercedes Benz 300D - ACM A/C Pressure Switch Part Number: W0133-162826
Description:
2 bar low pressure and 30 bar high pressure binary switch. This switch is designed to be compatible with R-12 and R134a refrigerants. Located on reciever-drier with 2 spade terminals. Used for compressor cut-out..

[Matt L]

Originally Posted by krwsenior

What is a binary switch? There were no options on the website when I ordered a new switch. My car has also already been converted. krw

Cphillip describes the binary switch above.

I would replace the receiver/dryer and that switch. You can simply drill a hole in the bottom of the old dryer to measure the oil, and put that much new oil in the new dryer. Do you know what oil was used for the conversion? The conversion sticker should say.

[cphilip]

Ok, I take part of that back... the Switch I see in mine has black plastic but it has a Silver nut area. Not Brass though... but not all Black either. Hard to say...

From catalog here...

Uniary 2 bar

Binary 2 bar/ 30 bar


Mine looks like neither....

[cphilip]

Originally Posted by Matt L

I would replace the receiver/dryer and that switch. You can simply drill a hole in the bottom of the old dryer to measure the oil, and put that much new oil in the new dryer. Do you know what oil was used for the conversion? The conversion sticker should say.

That sounds like good advice. So Dryer and Switch both and new oil. Sounds like a plan.

[sixto]

Does this model have a second pressure switch for the aux fan?

Sixto
87 300D

[cphilip]

Not certain... Tell me where to look and what it looks like and I will see if I can verify or not... AC's are somewhat foreign to me. But I am enjoying learning so far.

The closest thing near that area attached appears sort of like this one in this picture (labeled AC temp. switch)

[sixto]

That thing in my car taps into the refrigerant.

Sixto
87 300D

[cphilip]

Yea but not sure what it does from there...

[krwsenior]

This is the switch I ordered. Maybe I screwed up.
[IMG]https://www.***************/secure/PartImages/64531370463.jpg[/IMG]

I guess I should have ordered this part....
[IMG]https://www.***************/secure/PartImages/1248208310.jpg[/IMG]