Quick question re: bleeding the engine

[Steve_in_lex]

This is a basic question and I appreciate the help.  I'm a new owner and have a 2005 MK II with an M35 engine that I'm just starting to get to know.  I've read a lot in this forum about how to bleed the engine, but am unclear on the basics.  Given that the engine has a fuel pump, if I were to run out of fuel, would I still need to bleed it to get it going?  Thanks,

Steve

[Clay Greene]

I may be wrong but I thought the M35 is self-bleeding?  The engine bleeding discussion I have seen has focused on the M25XP engine.  But to answer your question, the air in the fuel line issue that requires bleeding is air between the fuel pump and the injectors, usually caused by replacing the spin-on fuel filter.  Running out of fuel would probably cause the same problem.  Others may have first-hand knowledge - fortunately, I do not. 

[travlinon]

claygr is correct the system is self bleeding. Turn the key and you should hear the fuel pump ticking over ( it is located at rear of motor just above heat exchanger). Leave on for a while then try starting in usual process (use glow plugs).
It is essential that pump is operating to get rid of air locks. I have previously had problems with air locks after changing fuel filter which  was because fuel pump was not working and no amount of manual pumping would clear it. If you have run out of fuel or changed the filter(s) it would be beneficial to remove as much air as possible before the above by filling the filter housings with clean diesel and doing a manual bleed using the bleed screw near the injector pump.The manual pump is situated in the primary filter.

Ken

[Stu Jackson]

Steve,

Yes, your engine is self bleeding, meaning you only need to get the fuel pump running to clear the air out of the lines.

However, on your engine, the only ways the fuel pump comes on is 1) by energzing the glow plugs when the engine isn't running; 2) when the engine starts the oil pressure switch re-energizes the fuel pump.

Be very careful, please about using the glow plugs to energize the fuel pump for the extended time you'd need to bleed. Maine Sail has warned against this, because extended run time on the plugs could burn them out.

The workaround is to install a simple toggle switch to energize the fuel pump without energizing the glow plugs for extended periods to bleed.

See page 3 of the Critical Upgrades topic, Bleeding M35 Engines.

[kwaltersmi]

For clarity sake, the M25XPB is also self-bleeding/priming, just like the M35.

Here's what the manual for each says about bleeding fuel:

"If it becomes necessary to bleed air from the on engine fuel
system, tum the panel key ON and impenitently (5- 10 seconds)
activate the pre-hear circuit. This activates the fuel pump which draws fuel into the on engine fuel system and drives air out via the fuel return.

If high pressure injector lines need to be bled, loosen the
injector line nut at each injector, open the throttle and crank
the engine over until fuel sports from between the nut and
line. the secure the nuts and start the engine as normal."

[Roc]

When changing the fuel filters (Racor and engine mounted), I fill them with diesel fuel when installing. This way, there is not much air in the system and letting the fuel pump run several seconds gets the engine to start right up.  I also have a little hand pump on top of the Racor filter if I need to purge any air out.

[Steve_in_lex]

Thanks all, this is really helpful.  Sounds like I shouldn't need to bleed the engine but should know how to do so, just in case.

Steve