all fuel return lines split

[Boyd's Auto]

I have a 2006 2500 sprinter, 95,000 miles, about a month ago just after filling up I drove home and then noticed a fair amount of fuel leaking from the overflow hose. I pull off the plastic engine cover and all of the return lines were split, the first return line was off. I just replace the return line in May (part from Europarts SD). It looks as if there is high pressure backing up the low pressure return line causing the line to split and for the first line to actually come off. Any idea what would cause this - or is there something else it could be? The vehicle runs fine, just leaks a great deal of fuel from the over flow line.

Mike

 

[autostaretx]

Sure sounds like blockage somewhere down the line (such as the feed to the heat exchanger coils back at the tank).

Did a rock fly up and pinch the metal line(s)?

--dick

 

[Midwestdrifter]

Check the return line and the thermostatic valve and cooler in the back of the fuel tank.

 

[Boyd's Auto]

thanks, when I look at the thermostatic valve and cooler what should I be looking for? I do a great deal of work on vehicles and motorcycles but not overly knowledgeable about diesels.


Mike

 

[Douglas Hicks]

Does your Sprinter have plastic fuel lines? Those lines have a flare at the ends. I have had all of the lines replaced on the 2003, and none on the 2005.

 

[Nautamaran]

Start at the beginning: can you inject fuel freely into the rear (#5) injector return hose? If fuel flows, check the new fittings for a blockage. If not, then work your way down stream...

The injector return line joins up with the HP rail relief solenoid, and with the HP pump’s return flow (lube bypass and LP relief valve flow), then fuel goes back to the fuel tank thermostat, with hot bypass via the cooling coils, before going back into the tank. The hot return fuel is mixed with cold fuel from the tank and warm fuel pumped out again by the electric LP fuel pump.

Work your way through the system until you clear the blockage.

-dave

 

[220629]

First, what others said.

I have a 2006 2500 sprinter, 95,000 miles, about a month ago just after filling up I drove home and then noticed a fair amount of fuel leaking from the overflow hose. I pull off the plastic engine cover and all of the return lines were split, the first return line was off. I just replace the return line in May (part from Europarts SD). It looks as if there is high pressure backing up the low pressure return line causing the line to split and for the first line to actually come off. Any idea what would cause this - or is there something else it could be? The vehicle runs fine, just leaks a great deal of fuel from the over flow line.

Mike

New fuel could be involved, but if contaminated fuel were involved I would think that the fuel filter would load up and not plug things like the fuel rail solenoid or high pressure pump control valve.

New parts.
Return line? Were all of the return hoses replaced as an assembly? Europarts SD supplies quality parts, but in these days of worldwide suppliers consistent quality is sometimes an issue.

If all were replaced, does the rubber seem hard/brittle or too soft? Any other quality clues? If all weren't replaced, were the failed parts new or were they those parts left in service. If it was the plastic return line to the tank... nevermind.

I believe the fuel return also goes to a diverter component near the fuel filter.

Given all of the possible faulty components it may be easier to install a pressure gauge and first establish what your return system pressure actually is.

vic

 

[Midwestdrifter]

On OM647 engines the diverter valve is on the cooling coils? the OM612 has the thermostat/diverter on the fuel filter. According to Dr. A, debris can build up in the diverter valve. In theory it could bet plugged up? There is also a few sections of rubber hose, all of which could get pinched.

 

[220629]

... There is also a few sections of rubber hose, all of which could get pinched.

The possibility of that might be increased if the fuel tank was dropped to change out a plastic return line. Otherwise, the hoses on the coils seem pretty stout and pretty short.

 

[Midwestdrifter]

I did see one van with the cooler coils half hanging loose due to broken clips, that could pinch one of the short lines. The return line under the floor near the drivers feet has some history of breaking free of its clips. Which could also possibly cause occlusion. Mostly on on gasoline engines, but fuel line can also degrade and plug up narrow fittings. The factory hose is good quality though, so it would have to be a badly abused hose section, or an aftermarket poor quality hose.

 

[Boyd's Auto]

Th e return lines were replaced as a set (from Europarts SD) back in May. The van ran fine, and still does except for the leakage through the drain hose. As for the return hose the outer casings are split where they attach to the top of the injectors. The hose on the most forward injector had split right through and detached from that injector. If I replace the return hose can I remove the end from the fuel rail and see if it flows then continue down stream?


Mike

 

[220629]

Not that you asked.

... As for the return hose the outer casings are split where they attach to the top of the injectors. ...


Mike

That sounds to me like the hose is defective. If the pressure was too high the hose would pop off with no damage, or bulge to split in the center, not crack at the stressed ends.

I would replace the hoses and give it a test run before mucking around too much.

vic

 

[Midwestdrifter]

Multiple splits would be a sign of hose failure, not pressure failure. Some rubber is not alcohol or bio compatible.

 

[Boyd's Auto]

Greetings, I may have figured it out, I added some anti-gel - replaced the return lines. Tested it pout and it seems ok. There is a small leak still happening from the top of the second injector, probably a bad seal on the return line junction. I have contacted Europarts SD about the faulty lines (bought in May) but have not heard back.


Mike

 

[Boyd's Auto]

Update, I sent photos to Europarts SD and they were very quick getting back to me indicating that they had changed suppliers of the return lines and sent me a new set (no charge). They arrived the other day and are similar to the OEM braided lines, unlike the previous faulty set. I have not changed them over yet as it is hovering around -30 these days, just a bit too cold, maybe in a week or so when it warms up.

Mike