Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 11-16-2020, 08:54 AM
s2s s2s is offline
Registered User
Join Date: Jul 2020
Posts: 32
Pre Filter Air

1973 220d
Replaced the prefilter and there is an air bubble in it. Everything I have read on these forums say that is fine/normal and you can't get rid of it. But the car quit while driving and let me sit. Couldn't get the car restarted until I used a zip tie to pull the filter up so that the bubble went to the top/back and then rebleed the fuel system. See picture to see the bubble and the zip tie to my battery handle fix. Car runs great now and I guess I can just leave it zip tied to by battery permanently but just wondering why this happened, and what I did wrong, or why this caused me problems if it's normal. Did I not leave the line from the tank long enough and this caused the air bubble to float to the front of the filter?

Attached Thumbnails
Pre Filter Air-air-filter.jpg  
Reply With Quote
Old 11-16-2020, 09:24 AM
t walgamuth's Avatar
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 37,050
I think your starting problem was due to an air pocket elsewhere. I'd check all my fuel lines and look for an air leak on the suction line.
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
Reply With Quote
Old 11-16-2020, 06:47 PM
s2s s2s is offline
Registered User
Join Date: Jul 2020
Posts: 32
Hmm... maybe, but I changed all the fuel lines when I changed the prefilter, and put several miles and starts on it before it started to lose power and eventually stalled. Then all I did was the zip tie and bled the main filter screw followed by the injector lines and it has run perfectly ever since. Even if I did have a leak in one of the newly replaced lines it would have caused the issue again.
Reply With Quote
Old 11-17-2020, 12:47 AM
Registered User
Join Date: Aug 2010
Location: Sacramento, CA
Posts: 2,636
Perhaps an air bubble worked its way to an injector tube. Once there, it might keep the injector from popping, though likely will eventually get dissolved into the fuel to pass thru the injector. But, it would probably have to happen in 3 of the 4 injector lines to kill the engine. Anyway, your bleeding air out at the top of each injector fixed it.

I changed the pre-filter in my 1984 300D a few weeks ago since the hose was slightly kinked and I wanted to change to bio-fuel rated hose. Surprisingly, after using the hand pump to circulate fuel back to the tank, I wound up with no air bubble in the pre-filter. Seems like I always saw a bubble like your photo before. I didn't even bother cracking the banjo fitting at the main fuel filter while pumping, nor the injector tubes, and the engine fired right up and ran fine.

1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 01:29 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page