1. If memory serves, the intake is the grillwork between the back of the hood and the windscreen. 2. The blower uses a fair amount of power and could have hot spots, such bearings. 4. Holes in the firewall under the battery shelf are common.
I believe this ACC system has a temp switch on the engine that inhibits all heat functions (except defrost) until the coolant reaches about 100 degrees F, as I recall. I'm not sure what s sooty smell is. -----Original Message----- From: mercedes-boun...@okiebenz.com [mailto:mercedes-boun...@okiebenz.com] On Behalf Of andrew strasfogel Sent: Friday, April 20, 2012 4:44 PM To: Mercedes Discussion List Subject: [MBZ] W123 1985 300TD ACC (heating system) 101 So I am still stymied at the episodes of a sooty smell emanating from the air vents in my 1985 CA version 300TD wagon. I spent some time degreasing the engine and solving a minor antifreeze leak under the hood. Thee are still areas with encrusted oil - typical of so many W123 diesels -but when I pop the hood I cannot detect the same sooty smell that emanates from the air ducts. The first onset of the smell seems t start after the engine is warmed up to normal operating temperature but only after the heat engages (not when the blower first engages). The smell doesn't seem to linger all that long, and seems to stop (although air continues to come through the vents) when the ACC switches over to either outside air or recirculating air mode once cabin temperatures reach the temp indicated on ACC thermostat wheel. The smell may reappear later for no particular reason. My basic questions follow: 1) Where is the intake for the outside air? 2) Could smoky air smell be coming from some place other than the outside of the car? 3) Could oil somehow have been interspered inside the vent system, which might cause a burning smell to emanate when warm air passes through the interior duct work? If so, how could that be addressed? 4) Could there be a crack in the firewall that allows engine smells to pass inside the car (doubtful) As usual, thanks in advance for your thoughts, guidance,and sympathies (haha).. Andrew 1983 and 1985 300TD _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
