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Discussion Starter #1
Hi Guys

So i haven't been online for a while, due to work and arrangements for the upcoming wedding next year. here is an update to some of the problems i had. SO you might recall i had some issues with idling when the car got hot. Well i decided to pull the head off of my baby and guess what, the head gasket was gone between two pistons and a coolant port causing the car to build pressure in the radiator and when idling the pressure would run back to the pistons. Also had a crack in the intake manifold that i repaired along with a few vacuum hoses that where really brittle. her tranny has finally been rebuild and she was in a pretty bad shape indeed. so with all that said, it would appear that i might have over pampered her, as she will only blow hot air out the vents now... even with the AC set to the max. and this morning she has had intermittent idling problems which seems to be ignition related.

Any ideas what the AC issue could be i have checked the two valves and they are nice and loose inside there casing. i am getting power to the two valves so the wiring seems fine. Any ideas would be greatly appreciated.
 

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was going to say Duovalve, but it looks like you got that covered already.

Beats mine, My AC is ICE COLD, Unfortunately so is my HEAT! LOL
 

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Discussion Starter #4
Hey I am not the only one. :D

Thanks for the info, unfortunately my car is still old school so i got two dial's one that sets the fan speed and the other that selects the vents. Then i have two thumb wheels one for each side of the car. down the center of the control panel i have the normal Climate control switches Dry air, econ, Cycle, and rest. So i don't have a LCD display like that of the later models. I think those only came out in SA around 97 or 98.

Just as a matter of interest on my why home from work yesterday my car's idling issue became really bad, so i pulled over switched her off and disconnected the MAF. She started up first time and i was able to drive the full 30km home without a single issue. I drove back to work this morning with the MAF still disconnected and all is good, so at least i solved one of my issues. I will phone the dealership today and go get a new MAF (MB Sandton is only a 5 minute drive from my office).

Thanks for info regarding the codes.
 

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Hey umfetu, I just bought a C280 in SA and am moving to Pretoria next year. Mine is a '98 so I guess I won't have the simpler climate control, too bad.
 

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Hey I am not the only one. :D

Thanks for the info, unfortunately my car is still old school so i got two dial's one that sets the fan speed and the other that selects the vents. Then i have two thumb wheels one for each side of the car. down the center of the control panel i have the normal Climate control switches Dry air, econ, Cycle, and rest. So i don't have a LCD display like that of the later models. I think those only came out in SA around 97 or 98.

Just as a matter of interest on my why home from work yesterday my car's idling issue became really bad, so i pulled over switched her off and disconnected the MAF. She started up first time and i was able to drive the full 30km home without a single issue. I drove back to work this morning with the MAF still disconnected and all is good, so at least i solved one of my issues. I will phone the dealership today and go get a new MAF (MB Sandton is only a 5 minute drive from my office).

Thanks for info regarding the codes.
My guess, even though it is not sticking, that your duo-valve is not right. I am not sure how to test it electronically, but if you were to bypass/replace, my guess is that your HVAC system would stop blowing hot air.
 

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Sounds like pieces of that old head gasket may be keeping the dou-valve open. You could pull the connector off the dou and check the continuity (center post+right post, center post+left post) There are some previous posts about rebuilding these if need be and if you have the time, when I replaced mine I just purchased a new one. You could also disable the auxially pump and temporarily pinch the hose leading to the dou to narrow down the search. Was the a/c working fine before the major operation? If not the next step might be a sensor issue.
I would also check your freon levels at operating temp.

V12 Uber Alles, Rear AC System and Duovalve Diagnosis Rebuild in a W140 Mercedes Benz


http://www.benzworld.org/forums/w210-e-class/1350793-duovalve-removal-cleaning.html

Let us know what the outcome is...B
 

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Discussion Starter #8
Hey guys thanks for all the help, but i found the problem last night after fitting my brand spanking new, freaking expensive MAF sensor. I opened the DUOVALVE and found that the in the middle top of the metal pods, they have little rubber caps. (I would suppose that these would be the rubber seals that stops water flow when using the AC). The driver side pod is fine which is also the side that cools and heats, but the passenger side pod, the rubber is completly worked away, also the side that only blows hot air. So Duovalve replacement is the way to go... Question is this though. Only my fiance rides shot gun so do i keep it blowing hot?? "Yes baby it is hot in here... take of that top... OOPS Speed bump" :D
 

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Discussion Starter #9
Sounds like pieces of that old head gasket may be keeping the dou-valve open. You could pull the connector off the dou and check the continuity (center post+right post, center post+left post) There are some previous posts about rebuilding these if need be and if you have the time, when I replaced mine I just purchased a new one. You could also disable the auxially pump and temporarily pinch the hose leading to the dou to narrow down the search. Was the a/c working fine before the major operation? If not the next step might be a sensor issue.
I would also check your freon levels at operating temp.

V12 Uber Alles, Rear AC System and Duovalve Diagnosis Rebuild in a W140 Mercedes Benz





http://www.benzworld.org/forums/w210-e-class/1350793-duovalve-removal-cleaning.html

Let us know what the outcome is...B
:bowdown::bowdown::bowdown:

That is perfect thanks. I have tested the coils and they where good i think it might be an issue with the bottom end where they got the two tapered needles. i will have a look tonight and let you know.

:bowdown::bowdown::bowdown:
 

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We're all the same...

There's proof that Men are all the same around the World!:D

Keep it Hot Baby!;)

Good Luck!:thumbsup:

C as in 220
 
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