A/C overcharged? high engine load, increased running temps, stalled...thx for input - Page 3 - PeachParts Mercedes-Benz Forum

leathermang · #31 04-02-2011, 08:14 PM

Ideally the test would involve a good squirrel cage fan directly blowing into the radiator..
Did not see that link....
Your service man should not have used the word Freon on that ticket...
he shows two bottles or cans... PLUS a conversion something..
can you get more info.. like the weight of those contents...
We need pictures of your service valves..
where he installed the refrigerant...
and any and ALL information stickers he installed on the car..
like " this car has been serviced with R134a refrigerant "... and take off the caps.. to see if he installed the proper fittings necessary by EPA rules for the R134a... good pics will allow us to determine that ....

leathermang · #32 04-02-2011, 08:24 PM

79 Mercy , thanks for the AC id...
I specialize in the type I system... can you tell me where the compressor cycling switch is located on his ?
I can get my books out... but you probably know offhand...

tangofox007 · #33 04-02-2011, 08:28 PM

Quote:

Originally Posted by 79Mercy

In much cooler weather the compressor will cycle as needed,

Because of the evaporator temp regulator preventing evaporator freeze-up. Not the same as a cycling system.

79Mercy · #34 04-02-2011, 08:32 PM

Leathermang, as tango stated it is not a "cycling switch", it is a switch that cuts the compressor off to prevent the evaporator from freezing up, which would only happen in cooler temps.... On the W123 evap boxes that switch is mounted behind the glove box with a temperature wire running into the evap case to sense temp. Im guessing its in the same spot on the W116 evap case.. ACCI has the same device.

leathermang · #35 04-02-2011, 08:34 PM

Quote:

Originally Posted by tangofox007

Because of the evaporator temp regulator preventing evaporator freeze-up. Not the same as a cycling system.

If it does not turn off the compressor.. how does it control it....to keep the evaporator from getting below 32 degrees.. thus freezing moisture content of the ambient air... on the outside of the evaporator.... causing the air to not be able to flow past the fins...
when it showed a TxValve..which is typically a combo block valve in our cars...
I assumed a cycling system ...
A non cycling system usually has an orifice instead of Txvalve....and an accumulator instead of reciver/dryer...

leathermang · #36 04-02-2011, 08:35 PM

Ok.. so it IS a cycling System...
but you do not want to call that particular switch a ' cycling switch' ? Ok with me...LOL

vstech · #37 04-02-2011, 08:37 PM

looks like the prices are pretty decent actually, I would have charged more.
I would NOT have installed 134 in that car though. the engine temps are high, do they drop if you shut off the a/c?
as long as the temps do not EXCEED the 212 mark much you are OK. (that 3/4 mark is 212F not 190...)
I'm worried that the evaporator is packed. no way 24 oz or even 32oz (depending on weather or not, he used 2 lbs or 2 cans of "freon"
is correct. the bill also doesn't state how much or what type of oil was used...
compressorworks is a great brand compressor. I'd have a 4th bolt installed in the lower bolt hole through the compressor to keep it from rupturing.

leathermang · #38 04-02-2011, 08:39 PM

Quote:

Originally Posted by 79Mercy

Leathermang, as tango stated it is not a "cycling switch", it is a switch that cuts the compressor off to prevent the evaporator from freezing up, which would only happen in cooler temps.... On the W123 evap boxes that switch is mounted behind the glove box with a temperature wire running into the evap case to sense temp. Im guessing its in the same spot on the W116 evap case.. ACCI has the same device.

Ok... so this switch is NOT integrated with the Txvalve ?
You are describing a normal thermosiphoning switch... which turns off the compressor on the low side temperatures....
but are saying something else controls the ' need more cooling ' turn on of the compressor ? Would you call THAT switch a ' cycling switch ' ? and where is IT ?

79Mercy · #39 04-02-2011, 08:43 PM

no this is not integrated with the Txvalve.

Let me look around and see if I can find you a picture of the switch we are talking about.

However after i post this pic i feel we need to get back on topic and help out the OP.

leathermang · #40 04-02-2011, 08:48 PM

Quote:

Originally Posted by 79Mercy

no this is not integrated with the Txvalve.

Let me look around and see if I can find you a picture of the switch we are talking about.

However after i post this pic i feel we need to get back on topic and help out the OP.

UH... I think knowing what system it is, how it functions, how to separate those functions and TEST them... and integrating that with his symptoms IS helping out the OP....

sshanky · #41 04-02-2011, 08:48 PM

I just shot a quick video of the compressor going on and off, but the engine was cold so it was hard to notice. This issue happened yesterday while it was hot out, and after a drive with the a/c on.

Here's a second video I shot, showing the engine starting and then turning it off, all while the compressor is switched on. notice the funny noise that you hear when the engine is shut off. this is heard only when the a/c is on.

http://www.youtube.com/watch?v=eKeQtQHSYh8

79Mercy · #42 04-02-2011, 08:50 PM

i drew an arrow to the switch which detects evap temperature and cuts the compressor to avoid freezing the evap.

sshanky · #43 04-02-2011, 08:51 PM

I will be leaving soon for the evening, in about an hour. I'll try to keep the A/C on, and then when I arrive, I'll shut it off, then turn it back on...would that help? tell me what to do , and I'll try to do a video of it.

thanks again everyone...this is fun, actually! am I the only one enjoying it?

leathermang · #44 04-02-2011, 08:52 PM

79Mercy, I do not think you pic posted correctly... and I could not put that into location box and go there either.. can you try again ? thanks,
Ok now I see the picture... I guess I will have to get the books out to deal with this... if the car has a txvalve.. that wouldl usually include the function you attribute to this switch...
So yall may have to finish with the puzzle....

79Mercy · #45 04-02-2011, 08:53 PM

Quote:

Originally Posted by leathermang

UH... I think knowing what system it is, how it functions, how to separate those functions and TEST them... and integrating that with his symptoms IS helping out the OP....

Yes, but the OP is having a problem with the compressor putting a excess load on the engine, not the evap freezing up.

EDIT: i fixed the picture