[W126 Coupe] Nippondenso Compressor

[Dick Spellman]

Hi Dan,

Chet's instructions and 'various pictures' will prove useful.  If you go 
to the last image on the right and look closely you will see the four 
hex bolts that hold the top cover on the compressor in place.  Under 
this cover are either 4 o-rings or a rubber molded maze that holds all 4 
o-rings together so it is a one piece replacement of all the rubber o-rings.

I have never done the detail of work Chet shows but thanks Chet, that's 
a keeper for somewhere down the road.  I did follow a set of 
instructions from Mike Ramay 7-8 years ago and replaced the  o-rings 
under that top cover using a kit labeled 'Asian Compressor Seals' and a 
small bottle of NYLOG o-ring sealant.  I went directly to MB dealer for 
the (2) manifold seals where the hoses are fitted.  The Nylog goo will 
help to hold the rings in place at the hose manifold.

I did replace the receiver/dryer and expansion valve (this valve is a 
PIA).  I added 2.5 ounces of PAG46 directly to the compressor on 
re-assembly of the top cover and 1.5 ounces into the low pressure hose 
valve immediately after vacuuming the system down.   When I vac'd the 
system down, I let it sit overnight with gauges to see if there were any 
leaks.  With none found, recharged with R-134a.  I set the low side 
pressures at 80F to the high side of the scale.  Don't have my notes on 
this handy but, think low pressure 45 or so.

This system I still have running is a Nipponsenso 10P17?? and  blows 40F 
at the center vents on MAX with fresh air door RECIRC (if so equipped) 
flap closed.  I also did all vacuum elements at the same time.  All but 
one vac element rubber diaphragm had failed after so many years.  Even a 
small crack in a diaphragm will prevent proper pull of the flap 
linkages. I do believe a number of warm air complaints can be attributed 
to the fresh air door vac elements (2) leaking and/or the center 
vent/defrost vac element leaking.  So, if you are going to do the 
compressor, plan on doing the vac elements for good measure so hopefully 
you get another 10 years without a problem.  I will mention, I pretty 
much looked to zero clock the ACC systems on these rebuilds and 
tested/replaced the ACC pushbutton unit, heater solenoid valve, aux heat 
coolant pump.  In every case, I have replaced the ACC push button and 
mono-valve.  Only one aux heat pump showed bad and needed replacing.

If you do choose to rebuild the compressor, I used Arizona Air for the 
Asian 'gasket' kit and Nylog <http://www.ackits.com/>.   Vac elements 
were Performance Analysis Co. </GEORGE MURPHY/. (865) 482-9175 (Voice or 
Fax) M-F 9am to 5pm ET  george_murphy at compuserve.com.>

The only other caution worth mentioning is that on occasion the 
compressor clutch will fail (chatter is typically heard) and rebuilding 
this may be necessary.  I'd guess doing it all at once makes good sense.

Rebuilt compressors with new clutch can be found here in the US for 
<than $400 too.

Good luck,
Dick
in Boston, MA USA where it's gonna snow and snow some more



On 1/11/2011 1:42 AM, Dan Gardner wrote:

> Hi Folks

>    Going back a couple of years,I had a R134a conversion by a mobile 

> "German Factory Trained"mechanic who turned out to be illegal, 

> unregistered and let the R12 into the atmosphere(I could have done 

> that and saved a huge amount of money but trying to be a "Greenie"I 

> got this clown!!).It didnt last long as a hose had swelled up.So I 

> replaced the hoses with the correct ones for R134A and fitted new "O" 

> rings which were also compatable.Had it pressure tested and regassed 

> once again it didnt last long as now it has compressor seal leak.The 

> A/C shop is quoting me $1200 to replace the Compressor(Non Genuine) 

> with a new one,claiming rebuilt ones dont last.

>

>    So I have a few choices

>

>    1/Replace the seals on the comp(shaft wear may be an issue) myself 

> refit and then get regassed

>    2/Buy a new aftermarket  comp

>    3/Buy a new Nippondenso comp

>

>    I don't use this car a lot,mainly for car club use and the 

> occasional weekend so the A/C seal may be prone to drying out.Any 

> advise welcome

>

>

>                                                                             

>                    Kind Regards Dan Gardner 1986  560SEC  Euro (220kw)

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.


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