Date registered: Aug 2009
Vehicle: '72 250C, '74 280C, '85 500SEL, '81 300CD.
Location: Tucson, Az.
Mentioned: 3 Post(s)
Quoted: 72 Post(s)
My '74 280C does the gas smell thing between 7/8's and 3/4 of a tank. Haven't figured it out yet. I've gone with checking the lines to the expansion tank, checking the diaphragms, changing the cap, replacing the sender gasket and haven't found the cause. Let me know when you find a cure.
I've been thinking about adding a secondary vapor canister where the vent line connects in the front fender well area.
I notice it the most driving with the DS window open so I'm pretty sure it is something to do with the stock vapors tank.
My suspicion is the oxygenated fuel we are getting now. It vaporizes and re-condenses in the vapor canister at a rate greater than the older fuel the cars were designed for and overloads the fume recovery system. This is why I am considering the second canister which hopefully will be enough vacuum load to pull off those fumes. It's worth a try.
Last edited by Mike D; 08-12-2013 at 11:57 AM.