Self-bleeding function
 

'82 240D, 190k, manual trans.: Had a fuel problem in January. Tank cleaned, strainer replaced, system fully flushed. Very clean fuel now, after two cycles of filters in 1000 miles.

After the last filter change, I bled the engine at the discharge banjo nut on the secondary filter, and it started immediately. However after three days of running errands and then sitting a day, it needs bleeding again.

The book speaks of the engine bleeding itself when running. I presume that's a function of the injector pump. I wonder if a piece of that crud that was in the fuel system got in there and is keeping it from evacuating air from the system.

Any thoughts on this? Can I fix this problem?

John Bonds
Charleston SC

Did you replace the crush washer on the filter bolt?

bops,

Air in the fuel system is bled thru the top of the fuel filter not the IP. This air is returned to the fuel tank along with the overflow fuel from the injectors.

Any air that gets into the pumping elements of the IP is pumped thru the injectors along with the fuel into the pre chamber.

P E H

Thanks!
 

1. No, there wasn't a crush washer in either filter box, so I didn't replace it. I'll get one today!

2. Roger on air in the IP, and the education on how it self-bleeds while running. I shoulda realized that.

I appreciate the help, guys.

bops

Some people swear that you need to crack that screw on top of the spin-on when bleeding the system, but it just is not necessary. The engineers took care of it.