Hi everyone. I'm really hoping that you can help me with this one. I'm posting on behalf on my dad who isn't on-line.
He has a (self maintained) 1998 Merc C250TD (saloon). He has owned it for around ten years and he does the majority of the maiteneance himself without any issues. Believe it or not, this car has covered just 58k miles(!)
Following a routine diesel filter change, the car developed a starting problem. She'd need to be cranked over like an old 54 seater coach before she'd fire. I looked at the issue with dad and noticed straight away that there was a significant amount of air in the transparent diesel fuel lines that lead from the fuel filter housing to the fuel pump. And that the engine only fired once the lines had all re-filled with fuel again - which makes complete sense really.
On removing the 'banjo' bolt (?) that holds the filter in place - I noticed that the lower of the two rubber seals was missing. We got a replacement seal and fitted it. Cranked the car over and she eventually fired and ran perfectly.
This had been the case prior to replacing the lower rubber seal but the starting/air issue has then reappeared the following day - or after the car had been stood (on flat ground) for a number of hours.
My dad has just been in touch to say that the issue has returned. He can't see whether there's any air in the fuel lines - but I'm guessing that there is.
The only other point worthy of note is that the 'banjo' bolt took some force to get it to seat back in to place. I am wondering whether we have been supplied with the correct size seal as it did seem quite proud of the tread on the banjo bolt(?). I also had to tighten it up using the thread on the bolt (normal, I'm sure) but I'm now wondering if the seal moved under the force and migrated up the bolt and has caused the issue to return - if this is where the air is getting in(???).....
So, in summary;
the engine will not initially fire following being stood for more that 5-10 hours.
there's visible +++ air in the fuel lines.
she only fires once the air has dissipated.
the engines runs, drives and pulls perfectly once it's going but it takes loads of cranking.
the problem then returns after she's been stood over night.
this has only occurred since the fuel filter was last replaced and (on re-inspection) the lower of the two rubber seals was missing from the bolt that holds the filter in position.
I've replaced the missing seal but think it might have maybe 'rolled-up' the bolt on replacing it as there was a large resistance when I was tightening the bolt.
Is it possible that air might be getting in here (if the seal has been displaced) or are we looking in the wrong place?
Any help would be very much appreciated.
Many thanks,
Adrian.
He has a (self maintained) 1998 Merc C250TD (saloon). He has owned it for around ten years and he does the majority of the maiteneance himself without any issues. Believe it or not, this car has covered just 58k miles(!)
Following a routine diesel filter change, the car developed a starting problem. She'd need to be cranked over like an old 54 seater coach before she'd fire. I looked at the issue with dad and noticed straight away that there was a significant amount of air in the transparent diesel fuel lines that lead from the fuel filter housing to the fuel pump. And that the engine only fired once the lines had all re-filled with fuel again - which makes complete sense really.
On removing the 'banjo' bolt (?) that holds the filter in place - I noticed that the lower of the two rubber seals was missing. We got a replacement seal and fitted it. Cranked the car over and she eventually fired and ran perfectly.
This had been the case prior to replacing the lower rubber seal but the starting/air issue has then reappeared the following day - or after the car had been stood (on flat ground) for a number of hours.
My dad has just been in touch to say that the issue has returned. He can't see whether there's any air in the fuel lines - but I'm guessing that there is.
The only other point worthy of note is that the 'banjo' bolt took some force to get it to seat back in to place. I am wondering whether we have been supplied with the correct size seal as it did seem quite proud of the tread on the banjo bolt(?). I also had to tighten it up using the thread on the bolt (normal, I'm sure) but I'm now wondering if the seal moved under the force and migrated up the bolt and has caused the issue to return - if this is where the air is getting in(???).....
So, in summary;
the engine will not initially fire following being stood for more that 5-10 hours.
there's visible +++ air in the fuel lines.
she only fires once the air has dissipated.
the engines runs, drives and pulls perfectly once it's going but it takes loads of cranking.
the problem then returns after she's been stood over night.
this has only occurred since the fuel filter was last replaced and (on re-inspection) the lower of the two rubber seals was missing from the bolt that holds the filter in position.
I've replaced the missing seal but think it might have maybe 'rolled-up' the bolt on replacing it as there was a large resistance when I was tightening the bolt.
Is it possible that air might be getting in here (if the seal has been displaced) or are we looking in the wrong place?
Any help would be very much appreciated.
Many thanks,
Adrian.
