anghrist

Hey folks. I was wondering if it is normal for there to be air bubbles going from the feed pump to the fuel filter on my '99 Turbodiesel. I was talking to myself in another thread, but this time I'm requesting help. I took my car to the dealership to have the problem analyzed. They changed filters (I could have done that myself) and charger me $150 and said that would fix the problem. The air bubbles are still there. I called the service dept. and told them that the bubbles are still in the lines. They replied that the bubbles are a characteristic thing for that car and that as long as they are not going from the filter to the IP that everything is fine.

Now I'm no MB tech, but I would think that the fuel system is a closed system on anything that involves injection. My girlfriend's '77 240D doesn't have air in the fuel lines and it's thirty years old.

My question is... Is the dealership steering me straight here or are they feeding me a load of hooey??

Thanks in advance for any help.

Iain

Have you changed the o rings on the fuel lines themselves? For a few dollars at the parts dept. why not diy!

harkgar

I think I replied to you a while back. I can only speak with my experience with a 1999 VW TDi. That car had a lot of bubbles in the fuel tube (transparent plastic thing) and had no other untoward symptom at all. If it is the same for you why should you worry?

anghrist

Well, If it weren't stumbling and stuttering then it wouldn't really concern me. I did take the time and money to R&R the old lines, shut-off valve, and seals on the fuel system. Made a huge difference. I did find some residue under the shut-off valve and on the front of the lift pump. I think it had a minor seepage there, but it was sucking in air in this area in a big way. Every morning it was *start* *stutter* *stumble* and then once it warmed up it would only stumble on the highway once every 10 seconds or so. Nothing major, just a little jerk in the frame like the fuel was suddenly cut off.

Fixed now. ONLY bubbles that appear are before the prefilter when the engine is shut off. This goes away when the engine is started and run for about 1 minute. So as far as I'm concerned the problem is fixed.

I also took the opportunity to change out the idler pulley and dampner, viscous fan clutch. Now I have the change flex disks, oil & filter and find a way to stop this infernal seat frame from popping.

harkgar

Anghrist,

Have you tried posting on the tdiclub site? Lots of technical postings there and they know all about diesel engines.

anghrist

I didn't try that yet, but the problem has been fixed for the moment or 100k miles whichever comes first.