fuel line vibration

[deepminer]

Just purchased an 2005 Interstate with 65k mile and had all the fluids changed,motor oil & filter, transmission fluid & filter, and engine air, and fuel filter. Since changing the fuel filter there has been a noticable sound due to the fuel line vibrating. I took it to the Mercedes dealer and they said it was due to the way the line was mounted to the vehicle frame and were not overly concerned, my question is this normal or is this due to fuel filter or fuel pump problems?
Thanks
Coal Miner

[73shark]

Welcome to the forum.

Not sure if it's normal but personally I'd want to do something to dampen the vibration. Vibration = movement = stress = breaking.

[Protagonist]

Originally Posted by deepminer

Just purchased an 2005 Interstate with 65k mile and had all the fluids changed,motor oil & filter, transmission fluid & filter, and engine air, and fuel filter. Since changing the fuel filter there has been a noticable sound due to the fuel line vibrating. I took it to the Mercedes dealer and they said it was due to the way the line was mounted to the vehicle frame and were not overly concerned, my question is this normal or is this due to fuel filter or fuel pump problems?
Thanks
Coal Miner

It is not normal. If it vibrates now, and didn't vibrate before, then something changed.

Vibration— by itself— is ineascapable, as long as the fuel line is connected to the engine. The fuel line should be flexible enough to account for that movement. It's only when the vibration results in contact where contact isn't supposed to happen and the line is chafing that it's a problem.

Knowing exactly where the noise is coming from is the first step to fixing it. With the engine running, visually trace the fuel line from the tank to the engine. In order for the vibration to make a noise that you can notice over the sound of the engine, the fuel line has to be in "loose" contact with another part, probably the chassis. Find that point, and you can pad the fuel line with foam insulation taped in place over the line, or retighten a loose fuel line bracket, or whatever fix seems best to you.

[73shark]

Not sure what it takes to replace fuel filter but if it requires removing some attachment points then maybe they forgot to re-fasten one or more of them.

[deepminer]

Thanks for the advice,I'll try to tighten or insulate the fuel line clamps and let you know what happens, the vibration can be heard over the engine and will continue when the engine is turn off till the fuel pressure kicks of the pump which I assume is electric and in the tank.
Coal Miner

[Protagonist]

Originally Posted by deepminer

Thanks for the advice,I'll try to tighten or insulate the fuel line clamps and let you know what happens, the vibration can be heard over the engine and will continue when the engine is turn off till the fuel pressure kicks of the pump which I assume is electric and in the tank.
Coal Miner

Come to think of it, there's another possibility. When you open up the system to replace the fuel filter, you let air into the fuel lines. Did you bleed the diesel lines after changing the fuel filter, to get the air back out? If not, you may have air trapped in the system, causing the diesel-fuel equivalent of "water hammer". Before you ask, I have no clue how you would bleed the air out of a fuel line in a Sprinter.

This possibility occurred to me when you said the vibration is keyed to whether the pump is running, not keyed to whether the engine is running.

You probably have two fuel pumps, a low-pressure pump to get fuel from the tank to the engine, and a high-pressure pump for the fuel injection. If you have a "common rail" fuel injection (BlueTec) engine then you certainly have two separate fuel pumps. The low-pressure pump is most likely the one that would be causing the problem in that case.

[wayneskid]

Originally Posted by Protagonist

.....If you have a "common rail" fuel injection (BlueTec) engine .....

To avoid possible confusion, common rail does not necessarily = BlueTEC. My 2010 Interstate on a 2008 FL Sprinter has the OM642 common rail diesel 3.0L V6 (there is even a CRD abdge on the rear door) but is NOT BlueTEC, for which I am very thankful.

[Protagonist]

Originally Posted by wayneskid

To avoid possible confusion, common rail does not necessarily = BlueTEC. My 2010 Interstate on a 2008 FL Sprinter has the OM642 common rail diesel 3.0L V6 (there is even a CRD abdge on the rear door) but is NOT BlueTEC, for which I am very thankful.

You are of course correct. BlueTec is common rail, but not all common rail is BlueTec.

[deepminer]

the engine is the 2.7 5 cyl. inline and I,m sure it has rail injection but its not the newer bluetec rail that the v6,s have, dont know a lot about the rail injection system,but I have an ideal that I need to learn

[wayneskid]

Deepminer,

Depeding on the model year of your Sprinter (which probably has a different MY than Airstream gave the Interstate), you could have either the OM612 engine (MY 2000-2003), or the OM647 engine (MY 2004-2006). Both are 2.7L, inline 5 cyl. Common Rail Diesels. The HP and torque specs are the same for both. If you have them side by side, the most visible difference is the intake manifold. I don't know what the internal differences are.

If you really want to understand what your vehicle (the Sprinter) has, the options it was built with, etc. I suggest you subscribe to EPCnet where you can see the same parts information that MB uses specific to your vehicle VIN. The cost is $12/yr. Or, send me a PM with your Sprinter VIN (not the Airstream serial number) and I'll run a data card for you that will show the exact MB factory build options in detail. They you would have a very small sample of what you can get from EPCnet. You can subscribe to EPCnet at EPC-net Online

Remember, knowledge is power.

Good luck,
Wayne

[deepminer]

Thanks Wayne thats great info,I,ll take your advice and join and by the way my engine is in an 04 chassis,and 05 airstream build

[wayneskid]

Originally Posted by deepminer

Thanks Wayne thats great info,I,ll take your advice and join and by the way my engine is in an 04 chassis,and 05 airstream build

According to what I'm seeing that means you have the OM647 engine. Good luck with EPCnet. It isn't particularly intuitive but there is a LOT of information there. If you haven't already been there, Sprinter - Sprinter-Forum is a great resource for Sprinter help and information.

Wayne

[deepminer]

I think the problem is cured,changed the rubber hoses on the fuel filter and the vibration is gone, just hear the sound of the electric fuel pump running

[73shark]

That's good news. Were the old hoses hard?

[deepminer]

yes and diesel fuel was seeping out at the clamps

[vswingfield]

Originally Posted by deepminer

yes and diesel fuel was seeping out at the clamps

And your dealer thought this was normal?

I don't know how your fuel filter is mounted, but most inline replacement filters come with new hoses. When you change the filter, you replace the old hose.

I realize that this doesn't apply to the more elaborate filter systems that commercial diesels use.

Still, I think I would be evaluating where this service was done.

[deepminer]

non oem filter, non mercedes dealer, sometimes you learn the hard way,but once you do it sticks with you.