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Discussion Starter #1
Where is the air conditioning expansion valve on the 1982 300SD? The dealer schematic shows it near the evaporator under the dash. I would hope for easier access than that. Are there old forem posts that would have more detail?

A mechanic friend says some of the older MB's have it mounted on the firewall inside the engine compartment. I do not see one there.

Any information helpful.

Thanks
 

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the expansion valve is located at he left rear of engine compartment next to the brake servo unit and yes it is located in the firewall. to have access on it you have to remove the wiper and its base. why replace it? does the aac doesn't get cold? goodluck
 

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Expansion valve

The answer to your response is in two parts.

No, the ac does not blow cold. If fact it does not work at all. The hoses from the compressor are leaking. Easy enough to replace. As long as the system is open I will replace all the seals and dryer as well. I have never been pleased with the performance of this ac unit since the car was new. Would not surprise me one bit if the expansion valve was bad, partially clogged or just defective from the factory. Only one way to find out.

I know several MB owners in the 80-82 range that had poor systems as well. They solved their problems by replacing all the above. Their systems now blow colder than when their cars were new.

I take it the expansion valve is on the engine side of the firewall. I cannot see it and the hoses to the evaporator appear to go thru the firewall.

Thanks for your help.
 

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have you checked the evaporator too? try removing the paneling side under the dash of passenger area. it leaks too most of the time. i have experienced even the early 2000 models is notorious on aac malfunction, replacing the expansion valve works most of the time not unless leaks is present.
 
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