Should probably be in the Vintage section, but figured it would be good for all to read.

As long as I have owned the 4.5, every now and again I would get the distinct smell of raw gas. It would happened especially if one window was cracked and the fresh air vent open. Couldn't really tell where the small came from. Questions posted on the rec.alt.mercedes newsgroup (a long time ago) were answered pointing to the fuel vapor recovery tank.

The idea was that after 20-30 years or so the recovery tank has been saturated or had absorbed enough fuel vapor to emit the smell. I always just sort of lived with it.

Last week, driving along, again I got the smell. Having had a bad day at work, I pulled to the side of the road determined to locate the source. Engine running, I popped the hood and immediately saw the source of the smell. The cold start valve was wet from fuel seeping out from the joint of the injector to the flange.

It wasn't dripping, just damp. Closer inspection of the intake and the immediate area showed minor traces of pooled fuel, long evaporated. With the engine running I could try to move the fuel line, which would cause the seep to stop or increase flow.

Replaced the cold start valve today and no more gas smell. Went on a 20 mile run, could not detect the slightest aroma of raw fuel. Looking closely at the old valve, now removed, there is a measurable amount of movement between the injector and the flange, but not very much. My thinking is that over the years the seal has worn/deteriorated and the slight movement allowed it to leak/not leak depending of how it moved. The injector is simply crimped into the flange (at least on the style valve I have).

Decided it would be better to share with all as every MB has a cold start valve.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.