6.9 refrigerant charge and expansion valve

[masakrer]

Hi Guys

Would you know where the expansion valve is located in RHD euro vehicle with manual AC
I will have to get into that soon.

Also what is refrigerant charge weight for 6.9 ?

[wbrian63]

On a LHD car, it's up inside the dash at the upper left hand side of the console where the A/C lines enter the evaporator. You can see it wrapped in nasty sticky tape above the accelerator pedal almost to the top of the dash cover.

Many things on LHD vs RHD cars are just reversed side-to-side, but I'm not sure if this is one of them.

If it's reversed, or if it is not, it's still waaaay up inside the dash.

I don't know what's worse when it comes to servicing these devices - dealing with the nasty tape that they must be wrapped in to combat condensation, or trying to get two wrenches at a time up into the small space, along with two hands to manipulate said wrenches...

[gavin116]

On RHD cars it sits on the right.  To access the expansion valve, you will need to remove the knee-rolls, and also remove the instrument binnacle.  The good Dr Bill did an instrument panel removal 101 (click here: http://forum.w116.org/interiors-and-exteriors/instrument-cluster-removal-101/).  In this instance, I would probably remove the steering wheel to gain access (says he with five thumbs: my car is having this exact work being done at John Haynes as I write this response).  Take note of his cautions: do not lean on the empty dashboard or it will crack, and do not start the car without the oil pressure pipe re-connected!  You should be able to reach in and see via the removed instrument panel and knee rolls. 


Someone may have a picture of what you are looking for but you could always search the forum for some pictures of dismantled dashes.  I think Mforcer has some good pictures (trawl through the pictures here, perhaps they may enlighten you: http://forum.w116.org/interiors-and-exteriors/rust-repairs-restoration/). 


The expansion valves are no longer available from M-B.  Ebay is your friend here: part number 115 835 00 72 freely available from Germany or the States, not sure if it is the same part for a 6.9, but it is for a 450SE.


The charge should be imprinted on the red sticker on the front crossmember that accommodates the headlights.  You can use a drop in gas like R22.  A change to R134 will necessitate all sorts or new parts and flushing, and it will be unlikely to run as efficiently as R12 (R22).


Hope this helps,


Gavin


Edit:  This thread may be better for pictures, but it is a LHD car.  Perhaps some of our Australian 116'ers may have some better pictures.  http://forum.w116.org/mechanicals/acc-overhaul-heater-box-evaporator-removal/

[masakrer]

Thank you for help.

That is what I needed.
My red stickers is missing but it looks like I need 1,2 Kg of R12 right ?
I will try to convert to R134.
I have managed to removed the expansion valve it was exactly where you said it would be

My ac guy managed to get expansion valve from Germany.

[gavin116]

Hiya Masakrer


I would stick with the R12, or its drop in replacements R22 and R417A.  The expansion valve is calibrated for R12 or R134, and I am led to believe that they are not interchangeable, although R134 will apparently work at lower efficiency with an R12 expansion valve.  (Not an expert here, but that's what I have been told.)  R12 and its substitutes use mineral oil to lubricate the compressor, whereas R134 uses PAG-46.  These oils are not interchangeable, and also require renewal of all seals and a good flushing of the entire air-con system.


You must also change your drier irrespective.  Here, I think you have lucked out, if I recall correctly the 116 036 (aka 6.9) uses a LHD dryer, which is available very cheaply.  The LHD dryer cannot fit the smaller RHD V8's (3.5 or 4.5) since the openings and window are reversed, which means it would need to be installed upside-down and back-to-front.  I may stand to correction, but I think there is another component that looks similar to a dryer that may need attention in the 6.9.  You can look what a 116 032 K-Jet set up looks like below.  ¿The 6.9 has the dryer on the other side, and there is a longer cylinder where my dryer is?


You are spot on regards the sticker.  What you can see is 1,0 kg for types 107 and 116, what's not so clear is the next bit of text: 1,2 kg for types 123 and 116 036 (aka 6.9) and the last line, 1,8 kg for the type W100 (Großer).  Once again the weight of gas is not the same for R12 and R134.


Hope it all goes well.  I'll post some pictures of my new set-up some time in the near future together with my replacement A6 aluminium compressor, some 20 Lbs lighter than the original, and very shiny.  Made in China like most things these days, but distributed by a USA dealer (sounds like our beloved Apple® products...) so its highly experimental.  Will keep the old Delco unit just in case, can always have it re-furbished if needed.


Good luck,


Gavin

[masakrer]

So I have managed to change expansion valve.
The compressor is new ( reman in USA) filled with oil compatible iwth R134.
I have charged with R134 we put 1050 gram which is 87% of R12
For now AC works fine ,having said that is now cold in London so no way of testing properly.
Blows very cold ,compressor kicks in as it should .
AC electric fan works as well.
So finger crossed.
After testing properly I will report.

[gavin116]

Looks like you're all done!  Perhaps we'll be able to put our air-cons to the test next bank holiday weekend.  And what a good-looking engine bay: the 6.9 is always heavenly to see, and not only is it very clean, but full of passivated metalwork. 


I am surprised just how lefty 6.9's are, I didn't fully realise that it extends to the radiator as well.  I see your oil cooler is also on the left as opposed to our smaller engined RHD V8's being on the right.


Keep 116'ing,


Gavin 

[masakrer]

Yeah
Hopefully the summer is not over yet.
I decided to work on engine bay as much as possible however did not want to strip the car completely.
We had the engine removed for paint job so it was good opportunity to work on details.
Today we have removed more engine bay bits to have it re-plated at Jackson Plating in hounslow.
I f you are around feel free to pop in to have chat.
I am located in Brentford.

[daantjie]

I may stand to correction, but I think there is another component that looks similar to a dryer that may need attention in the 6.9.  You can look what a 116 032 K-Jet set up looks like below.  The 6.9 has the dryer on the other side, and there is a longer cylinder where my dryer is?

Hi guys

I see in this post "another component that looks similar to a dryer" is mentioned on the 6.9.  as you look at the engine. Standing in front of my car (LHD US spec 6.9), I see this component on mine as well, with valve attached.  The red sticker stating Mercedes-Benz R12, and volume to be filled is right above this canister on the rad cross member.

Am I correct to assume that you fill this canister with the gas directly until you have added the max?  I bought a RED TEK fill kit, which is supposed to be a top up for R12 systems here in Canada.  Hoping I can just plug into this valve and fill, or am I missing something here?

Cheers

[KenM]

Hey Daniel,
Don't worry about this other component, it's just a damper, smooths out the refrigerant flow to cut down noise and ensure an even refrigerant flow and to hopefully prevent vapour bubbles in the liquid. You

don't need to replace it, nothing serviceable in there.

Cheers,

[daantjie]

Great thanks Ken!

P.S. I like your Breaking Bad reference avatar