E320 Cdi Fuel filter replacement

[seabadger]

I notice that MB recommend the fuel filter is replaced every 50,000 miles. As far as I can see my W211 has never had one (now 85,000 miles).

Is this a straight forward job?

This is my first diesel motor so am a bit clueless especially about bleeding the system? Does it self prime? Also I've read about filling the new filter with fuel before fitting ????

Would be grateful for any helpful advice.

 

[type49]

Easy job. Remove the engine covers, held on by 7 (I think) torx bolts, I think they are t25 size. With the covers removed, you will clearly see the filter, slightly to the right & towards the back of the engine. Remove the 2 pipes ( minimal fuel drips & not under pressure), loosen the 5mm allen key bolt that clamps around the filter, it doesn't have to be removed ( a bit fiddly but worth the effort ) The filter may well be stuck around the clamp & may need a bit of muscle. With the new filter on just crank it. It will self bleed but dont expect it to start on the button. Switch off fan, radio, headlight delay etc to help battery. Job done - you've just saved youself about £60!

 

[Sprint'n'Go]

I can definitely recommend pre filling the filter with diesel. I never used to bother but the last one I did was a pig and ran 2 batteries flat trying to start. I then removed the filter and filled it before trying again and hey presto, 5-10 seconds of cranking and bingo.

 

[television]

Do not use a cheap filter, do keep everything clean.

Malcolm

 

[seabadger]

Thanks for the messages of encouragement - this sounds like a simple job.

I can see the filter is a fair size and imagine it takes some filling. Wondering where to get the clean diesel from? From the old filter? I will buy a new one and suss the job out.

Thanks folks.

PS Enjoy your new motor Malcolm - I don't think they fit diesel engines in the SL Class - a bit too agricultural I would say!

 

[John Kerr]

When you next fill up at a garage fill a 2ltr bottle up you will then have enough for the next time.

 

[television]

PS Enjoy your new motor Malcolm - I don't think they fit diesel engines in the SL Class - a bit too agricultural I would say!

I had a tuition course on common rail systems a couple of weeks back,the filter is an important bit, I am past the days of slipping engines in and out,so the SL can stay as it is

Malcolm

 

[Parrot of Doom]

Might be an idea to buy some diesel injector cleaner and fill the new filter up with that.

The engine will run like a dog for a few minutes, but it can't do any harm and its easier than messing around with fuel cans and garage forecourts.

 

[seabadger]

Thanks for the tips folks. I'm not an additive fan so I'll stick to clean diesel. (My blood pressure couldn't stand it if she runs badly after I've been playing with it.)

 

[Bonzo Bob]

I know this thread is quite old but which are the input/output ports on the filter? One pipe is larger than the other!

Bob

 

[mioba]

replace as they came off.
The pipes on the filter should also be different diam.

if in doubt follow the pipes!

 

[Bonzo Bob]

Thanks Mioba,

I have also just noticed arrows on the top of the filter showing direction of flow so the larger pipe is the input which you would expect. I do intend to prime the new filter with fuel before I secure the 2 pipes.

Bob

 

[M80]

You will find it easier to return the fuel in the old filter to the tank.
When you turn the ignition the lift pump in the tank will fill the filter in no time. It will run the lift pump for approx 15 seconds till the ECU shuts it down due to no pressure in the common rail.
Cycle it twice to be sure but if you were to disconnect the line from the tank to the filter you could fill a bucket in seconds.

 

[Bonzo Bob]

I have read on this forum to prime the filter manually by simply poring in fresh diesel then reconnecting both pipes or else the engine will not start for ages! Is this true?

 

[M80]

If you're talking of your W203 646 engine I wouldn't anticipate difficulty.
The 2.7 5cyl engine of the same era was a real bitch, no lift pump.

While you have the lines off the filter it is fairly easy to confirm.
If you place the line from the tank (arrow in on the filter) into a container, if another turns the ignition to 2 (not to turn the engine over) the container should fill at speed.

All connected the filter will fill and the excess is returned to tank via the return line, until the ECU shuts down the lift pump.

 

[mioba]

I have read on this forum to prime the filter manually by simply poring in fresh diesel then reconnecting both pipes or else the engine will not start for ages! Is this true?

On engines 15 years ago.

You can also use a belows pump in the outlet to pull fuel through.

 

[Bonzo Bob]

Just to clarify matters my Merc is a 2003 E320 CDI I6 W211 ...... so will I be OK not priming the new filter with fresh diesel?