w126 heat exchanger-what is this?
 

Not sure if I'm posting this in the correct forum, or if maybe this is a second gen 126 thing and the 300SDLs have it... it being a mystery to us, thus i've come here. My friend Turbobenz pulled this out of a 420SEL. He found it wrapped in insulation in line with the compressor low side. He said it was full of fuel in the jacket. What is this doing to the fuel? or is the question what is this doing to the freon? Anyone know? has anyone seen this? It looks awesome polished!

http://i131.photobucket.com/albums/p...t/IMG_0976.jpg

Fuel cooler.

My 560 SEL has one also. It confused me at first sight also.

Why would the fuel need to be chilled? But only with AC? Or does this ad heat into the low side of the AC system to expand the gasses?

With the AC running, this line is chilled. Without, it still acts as a huge heat sink. But I am not sure how effective it really is on a return style system where fuel flows at a pretty good rate.

I scratched my head when I saw mine. Maybe it was designed to control vapor locking during hot summer AC use. Dunno.

It has the appearance of something used for distilling spirits.:rolleyes6:

Maybe you found another use for the Benz!:D

cool fuel is higher density, more power. hot fuel is lower density, perhaps it vaporizes too easily...
gassers... sheesh!

Not only is it a heat sink to cool the fuel on the return side but I imagine it also acts as a baffle to smooth out surges in the fuel supply.

The CIS system is a fairly primitive set-up. Effective yes but not exactly technologically advanced. 'Course, "if it ain't broke, don't fix it" is a pretty safe way to ensure reliability.

That's my guess as well

Why would adding heat to the low side prevent vapor locking in the AC? What is vapor locking? When it can't Compress the gas into a liquid on the high side?

You're looking through the wrong end of the telescope. The exchanger is removing the heat from the fuel not adding it to the freon. Well, actually it IS adding heat to the freon but the cooling system is designed to dissipate the heat whereas the fuel system is not.