Bleeding a diesel engine

Got talking to a bloke today at Tesco's while getting diesel. Long story short, I mentioned that I was running on fumes and glad that I did not have to bleed the engine if I had run out of diesel. He told me modern diesels don't need bled as the are self bleeding. When I got home, curiosity got the better of me, so checked the engine for a lift pump but could not find one. Is he correct? My thinking is that since there is an electric fuel pump in the tank, I would still have to bleed each injector as normal. What's your verdicts?

Billy

I seem to recall modern diesels are self bleeding but I wait for more opinions.

Musicmaker said:

Got talking to a bloke today at Tesco's while getting diesel. Long story short, I mentioned that I was running on fumes and glad that I did not have to bleed the engine if I had run out of diesel. He told me modern diesels don't need bled as the are self bleeding. When I got home, curiosity got the better of me, so checked the engine for a lift pump but could not find one. Is he correct? My thinking is that since there is an electric fuel pump in the tank, I would still have to bleed each injector as normal. What's your verdicts?

Billy

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Supposedly self bleeding but if there is enough air in the lines it's necessary to crack the feed line to the FIP and bleed the air out of the line and sometimes it's also necessary to crack the injector unions.

i once ran a hire car diesel out, all i did was fill it up from a jerry can and it worked again. I didnt know at the time that running diesels out could be a problem. Now i try to not go below 1/4 tank just to be safe - i do a lot of long commutes and dont want to get stuck in traffic and run out again (as happened in the hire car)

Most new diesels are meant to be self bleed as per datatek but most will need help bleeding as when cracking engine to purge system of air it can do twol things:
1 - flatten the battery
2 - overheat the starter motor
And still not start and can in some circumstances bring on the eml with a host of fault codes.

My old 03 vectra 2.2 diesel was a right royal bitch when it ran out took nearly 2hours of almosr constant cranking (on jump leads) before it started dont know if there was a fault somewere but i msde sure it never ran out again

Common rail diesels (M57) do not need bleeding as far as I know, indeed I don't think there is an easy way to manualy bleed them apart from the pressure check point on the common rail.

Also even if it does start again once ran dry expect it to start leaking fuel as the seals don't like being dry!

Unless the engine is cold pre 99 models will struggle to self bleed in the event of running out of fuel. Because the fuel lift pump does not run on cranking. That is when you will find out just how good your battery is. Post 99 should not be a problem. The injection pump will always self bleed providing the lift pump is running. The high pressure pump in the injection pump will blow any air out through the tank return. However if the injection pipes are empty as in the case of removing and replacing them, they will NOT self bleed unless they are cracked at the injectors. Pipes should be full if you run out of fuel so that should not be a problem. But best advice would be, DON'T run out of fuel.

Doesn't running out of fuel cause problems with drawing up all the rubbish from the bottom of the fuel tank? Or is that only with old engines?

gfromleeds said:

My old 03 vectra 2.2 diesel was a right royal bitch when it ran out took nearly 2hours of almosr constant cranking (on jump leads) before it started dont know if there was a fault somewere but i msde sure it never ran out again

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Vauxhall's don't have a in tank fuel prime pump so if you run out you need to hand prime fuel to high pressure pump to get it running, they can be hard to get going again

TCubed said:

Doesn't running out of fuel cause problems with drawing up all the rubbish from the bottom of the fuel tank? Or is that only with old engines?

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Fallacy. The fuel is always drawn from the bottom of the tank so any **** in there will be drawn out, old, new, full or empty.

Mine was a bitch to bleed. I would have said a good 15 mins of cranking

Primed to FIP connection by powering lift pump.

I eventually removed glow plugs and span it over with injectors loose until they leaked then tightened down. I had manifold off and it engine spins over better

glow plugs back in and freshly charged battery then it started.

Mamasbigtruck said:

Mine was a bitch to bleed. I would have said a good 15 mins of cranking

Primed to FIP connection by powering lift pump.

I eventually removed glow plugs and span it over with injectors loose until they leaked then tightened down. I had manifold off and it engine spins over better

glow plugs back in and freshly charged battery then it started.

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loosen the fuel line nut going to injectors. have some turn it over when fuel comes up tighten them one at a time. it will start to run on 2 in a few seconds all will fire. Had a farm tractor and when we ran out of fuel a 5 minute job to get it running again.