the vent fan doesnt work on my rusty beater 83.it is venting hot air out the vents.i have all the forward vents closed and it is venting hot air out the top.it is making me want to puke as it smells and it is 90 some degrees out side.i believe the heater valve is open ...is thier a link or a way to bypass the heater core or turn the valve closed or bypass the valve?i see three places where the engine coolant lines are going into the firewall.wich is the in and the out????

thanks

The heater core is supplied from the driver's side; near the oil filter. The return is up on the firewall on the passenger's side

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Probably a bad monovalve. Cheap and easy to fix with a new insert.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

my climate control doesnt work if at all.can i just bypass the monovalve.or maybe just unplug it.this is the device that is heating the coolant it up right?

^^Your CCU may have failed, a common occurrence. I understand bypassing the mono valve will result in constant heat.

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83 SD

84 CD

Simple fix is to bypass the heater core altogether. Replace the two coolant hoses from the cylinder head with a "U" hose.

Of course then you won't get any heat, ever.

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'98 E300 turbodiesel

i bypassed the heater core and didnt have to buy anything.dont plan on keeping this car tomuch longer.hoping to get rid of by christmas.looking at getting the wife a really nice bodied merc i hope.thinking 123 diesel 4,seems like there are 10 turbo diesel to every 1 4 cyl diesel 123 body that has handcranks and auto(if i got that i would put a manual trans in there later and have cruise control.)the way feul prices are staying low i may consider a 190 4cyl.probally not.since i live in oh man i want to rip my skin off it is so humid/hot for 8 months of the year floriduh i dont give @#$% about the heater in my beater.