Strange AC behavior: CCU? - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 06-24-2011, 12:12 PM

Quote:

Originally Posted by tangofox007

Just a quick touch on a Schraeder valve should tell you what you need to know.

I should do that... let me find it and report back.... Will all of them react to both R12 /R22( which it was bought for ) and R134a ?

tangofox007 · #17 06-24-2011, 12:14 PM

Quote:

Originally Posted by leathermang

I should do that... let me find it and report back.... Will all of them react to both R12 /R22( which it was bought for ) and R134a ?

Yes. Won't be nearly as sensitive for R-134a as R-12, but still plenty sensitive.

leathermang · #18 06-24-2011, 12:17 PM

Thanks... Now, what if I touch that valve and it sticks open and all my refrigerant spews out into the atmosphere ? EEEEKKKKK ...

tangofox007 · #19 06-24-2011, 12:20 PM

Quote:

Originally Posted by leathermang

Thanks... Now, what if I touch that valve and it sticks open and all my refrigerant spews out into the atmosphere ? EEEEKKKKK ...

I think that, if you buy some carbon credits from Al Gore, it will all be okay.

leathermang · #20 06-24-2011, 12:22 PM

Quote:

Originally Posted by tangofox007

I think that, if you buy some carbon credits from Al Gore, it will all be okay.

Can I use Paypal for that transaction ?

Goldenvoice · #21 06-24-2011, 03:44 PM

You guys are awesome

Well, here's where I'm at: The "good ole boy" tech will try again, investigating further, with out any added financial cost to me. So, with that in mind, I'll spend a few hours tomorrow (Saturday) with him, and see if 'we' can get the job done. He has several sniffers, and a unit with light and camera on the end of a wand...

Not saying it's the best way, but I'll give him another chance, for sure.
(and armed with a little peachpartsforumiteknowledge...)

So, charging the system with R22 (4oz) instead of R12? Is R22 a smaller molecule, or something? And the Nitrogen gas same?

leathermang · #22 06-24-2011, 03:57 PM

The use of 4 oz of R22 and nitrogen allows you to test under pressure...which is totally needed..nitrogen is a dry inert gas so it will not combine with the oil and produce any bad things...

AND

is EPA approved to be discharged into the atmosphere after you have found the leak... that is its advantage...and sniffers are sensitive to it..

They figure that is better than people charging up with R12 and then finding they have a leak....possibly slowly...... and losing that to the atmosphere...

whunter · #23 06-24-2011, 05:07 PM

Quote:

Originally Posted by Goldenvoice

82' 300TD - AC has not been functional for a couple years, and with summer lurking, I'm in the 'restore it' mode.

So I had a local AC/refridge repair guy dye the system yesterday, and he found the pump shaft seal to be bad. So he replaced the pump this morning, and recharged the system.

Bugger was: the clutch wouldn't engage... tested the voltage to the clutch, and it varied: sometimes 10v, sometimes more, but apparently inadequate amperage. A few tries had the clutch "trying" to engage, but not getting the job done (can you say clutch burn-out?) We double-checked the clutch with a set of jumpers direct from the battery - the clutch worked fine, and he charged the system using this method.

**I also noted the fuse currently installed is the next heavier than listed as correct (this by a previous owner), and the box at the upper end of the fuse has whitish 'flash' marks on it, where in the past the fuse has blown...

ALSO: I could not get ANY cold air out of the ducts in the cabin, even though the refrigerant part of the system works fine, (with the jumpers), [and the aux fan cycles]. This, we're pretty sure, is caused by a vacuum module not functioning (immediate cause unknown).

Do both or either of these issues point to the CCU? Possibly needing a re-solder? I know the CCU is tired, for starters as the center (floor?) button, and the 'economy' button do not trigger the fan, but the defrost and the 'up/down' button next to it run the fan fine...

Thoughts?

Possible issues:

* Defective device called "Temperature Switch" in EPC, and "Temp sensor or ETR anti-icing switch" in WIS.

* Defective CCU = Climate Control Repair on the 1983 300D Turbo (W123 Chassis).

* Defective mono valve diaphragm.

* Defective A/C Temperature Switch On Receiver Drier, (2 Spade Connectors) 6 mm Threaded Shaft MB# 000 820 80 10

* Defective A/C Pressure Switch On Receiver Drier, 9.5 mm Threaded Shaft (2 Spaded Connectors) (No Wire Lead) MB# 124 820 83 10

* Defective Receiver Drier MB# 123 830 06 83.

AC Question. Still HOT in Houston. Need expert opinion!
AC Question. Still HOT in Houston. Need expert opinion!

.

Yak · #24 06-24-2011, 06:04 PM

Quote:

Originally Posted by Goldenvoice

OK, the pollen from the grass field next door finally quit blowing for the day, and I was able to get out and play with this some more.

<>

Jumpered around the low-pressure cut-off switch on the dryer, and wha-la, the clutch snaps in and out with attitude

but... The best the system could muster in 15 min of running is the top tube on the condenser got just hot enough to make it hard to hold my finger against... ppppfffff

So I'm guessing I'm back at square one: a leaking system.

I just talked to the tech - we'll get back together tomorrow for a more thorough and more powerful black light inspection...

Drop the panel on the passenger side footwell so he can get the sensor in near the TXV and the lines to the evaporator. If the bulk of the leak checking was in the engine bay that may have been overlooked.

Check the high side port for a cap. It's on the bottom of the car, near the alternator.

Yak · #25 06-24-2011, 06:11 PM

Quote:

Originally Posted by Goldenvoice

82' 300TD - AC has not been functional for a couple years, and with summer lurking, I'm in the 'restore it' mode.

<>

Bugger was: the clutch wouldn't engage... tested the voltage to the clutch, and it varied: sometimes 10v, sometimes more, but apparently inadequate amperage. A few tries had the clutch "trying" to engage, but not getting the job done (can you say clutch burn-out?) We double-checked the clutch with a set of jumpers direct from the battery - the clutch worked fine, and he charged the system using this method.

**I also noted the fuse currently installed is the next heavier than listed as correct (this by a previous owner), and the box at the upper end of the fuse has whitish 'flash' marks on it, where in the past the fuse has blown...

ALSO: I could not get ANY cold air out of the ducts in the cabin, even though the refrigerant part of the system works fine, (with the jumpers), [and the aux fan cycles]. This, we're pretty sure, is caused by a vacuum module not functioning (immediate cause unknown).

Do both or either of these issues point to the CCU? Possibly needing a re-solder? I know the CCU is tired, for starters as the center (floor?) button, and the 'economy' button do not trigger the fan, but the defrost and the 'up/down' button next to it run the fan fine...

Thoughts?

Doublecheck the wires to the compressor clutch. The spade connector has a "spring clip" to grip the male spade on the clutch. If not re-installed correctly the plastic connector cover and the female spade end on the wires can be a "friction" fit between the cover and the connector instead of within the connector "spring" and be intermittent/loose.

By the "white flash" do you mean compressor fuse or blower fuse? There's a known problem for the blower (fuse 8, I think) that gets replaced by a strip fuse in the matchbox sized holder on the fender.

Goldenvoice · #26 06-25-2011, 12:39 PM

It did take me a couple times of fooling with the connector to the compressor before it 'clicked' solidly into place - strange little bugger.

Yes, it's the #8 fuse. So you're saying there's an aftermarket fix, with a 'slo-blo' or something? Or do I look into something factory on the fender well?

Yak · #27 06-25-2011, 04:42 PM

Quote:

Originally Posted by Goldenvoice

It did take me a couple times of fooling with the connector to the compressor before it 'clicked' solidly into place - strange little bugger.

Yes, it's the #8 fuse. So you're saying there's an aftermarket fix, with a 'slo-blo' or something? Or do I look into something factory on the fender well?

Post #4 in this thread links to other threads with pics, and a lot more links. w123 blower fuse?

The "fix" replaced the #8 fuse with a 30A fusible link/strip fuse in a little housing. (Pic in one of the links).

Goldenvoice · #28 06-26-2011, 11:26 AM

Saturday: back to Gypsy tech - he recovers refrigerant, then pulls out a big 2-stage commercial vacuum pump, and lets that baby suck on her for a while. Recharges the system, and this time we get cold air - 50 degrees at idle - parked. Ran for awhile, then shut her down, and found another leak with a sniffer. The 'plug' end of the expansion valve has a little leak, and dye is evident as well. So he tried tightening the plug (for *****s & giggles), said sometimes that works, and we pontificated on whether the 1/8" he turned it would change something in the balance of the system, and if so - what. Thats old-school tinkering for ya.

Town for groceries is 14 miles of open highway - she blew 80 degree air all the way there :/ - did some strange things in town between stores: start car, temp at nozzles dropped to 50, then slowly climbed back to 70 (ambient 75-80), with the compressor still running, but return trip of 14 miles, she blew air of 44 degrees...(?)

He rolled back under, and confirmed with sniffer and dye the expansion valve is still leaking, so I'll order one up on Monday.

Any thoughts on the "temp climbing with comp running" behavior?

ALSO: hi-lo (second button from left), and fan on high: seems to me the dash nozzles (and floor, for that matter) should be really blowing some air - I get air flow, but no real wind storm... sound normal?

leathermang · #29 06-26-2011, 11:49 AM

For standard comparison your blower needs to be on low... and the AC on max air... whatever dash buttons give you that for the pencil thermometer to give reading to compare with others...

It sounds like yall are trying to find leaks by vacuum...
not a good method...which it looks like you are slowly figuring out.... LOL

Have you cleaned the fins on the inside of your Evaporator ?
I assume this far along that the fins on condensor and radiator are cleaned AND straightened ?

Goldenvoice · #30 06-26-2011, 01:01 PM

It's not quite the blind leading the blind, but has had it's moments

Condenser and radiator are cleaned AND straightened.

How, pray tell, do I get into the evaporator?
And best method to clean?

I also plan to remove the ACC unit, and find those pesky little relays, and give their contacts a cleaning. Not sure I need to resolder the whole works, but will give it a thorough visual inspection.

Curious: at what point, or in what setting does the system go to 'recirculate' air?

And as far as the pencil thermometer and ACC settings, I roll the temp wheel to Min (clicks), but the fan is either on full, off, or auto (which steps up to high).

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