Clear line to OM606 IP popping off
 

So here's a fun problem. The plastic fuel line fitting (603 owners, I envy your banjo bolts) on the clear line to my IP keeps popping off.
The first time I put it back on, I noticed that the elaborately designed clip, which works something like a V-clamp for intake/exhaust fittings, was bent from the fitting being pushed out of the corresponding socket in the IP.
I bent the two arms that engage with the flange on the IP back into position, re-installed the fitting. No more than 200 miles later, it's already being pushed out and bending the clip again!
What gives? My fuel economy is in the toilet right now and I am not a happy dieseler!

The replacement part for that line actually has a banjo fitting. If you (or your dealer) look it up in the EPC you'll see the bolt and washers which have to be ordered separately.

I'd be a bit suspicious of it popping off in the first place though. What are the chances your relief valve is stuck and it is building too much pressure in the system? The valve is a spring and ball in the banjo bolt for the return line on the other side of the pump. If you pull the crossover pipe and use a ratcheting box end wrench you can get to it but only one click at a time. I've never heard of one sticking closed and usually the problem is that the spring gets weak and the pressure it too low. Have you put a new o-ring on the fitting? If so, what are the chances it was a bit too thin and is not sealing well enough?

This thread has the info on the updated line with the banjo fitting. After replacing all the o-rings on mine I'm leak free with the original fittings :)

http://www.peachparts.com/shopforum/diesel-discussion/238415-i-found-my-fuel-leak-om606-190-a.html

I haven't done anything to the fuel system besides replace filters and injector return lines, so it shouldn't be a leaky O-ring. The fact that they updated this part with a banjo bolt and fitting makes me think that this was a known issue. I'll order the parts from the stealership tomorrow and see if installing the new line fixes the leak (and associated poor fuel economy).