Fuel Filter - Volvo Penta MD2040

[landonshaw]

I currently have a Volvo Penta MD2040. This weekend I drained water and dirt from the fuel pre-filter. Some dirt was present but did not notice any water. Prior to starting the engine I had a conversation with a friend that suggested I fill the system with fuel and get rid of any air prior to attempting to start the engine. He said that if air got into the injectors I would have another project on my hands. I did as he said and the engine runs well.

Having read the instruction manual, it says nothing about bleeding the system. Is this something that has to be done after cleaning this filter? Next week I am changing the fuel filter. Will I have the same situation?

[markpj23]

The Volvo DIY Manual has a section on changing fuel filters and bleeding the system afterwards.

To paraphrase:
- the manual does not say to fill the new filter before putting it on
- it DOES say that you must open the air bleed port on top of the filter, then use the hand pump to force air out of the system - as evidenced by fuel eventually coming out of the air bleed port.

It will save you a LOT of time if you fill the new filter with fuel before installation. Then you will have much less air to purge from the system. This is good practice for all filters engine or genset.

Alternatively, if you have an electric fuel pump in-line, you can just spin on the new filter and run the pump for a while until the air is purged via the tank return line.

I have the Volvo DIY manual in .PDF form (3 files) if you want it. Send me an email / PM and I'll get it to you.

[AndyDG]

"It will save you a LOT of time if you fill the new filter with fuel before installation. Then you will have much less air to purge from the system. This is good practice for all filters engine or genset."

Actually...NO..this is extremely BAD practice for any filter!

By filling the filter manually before refitting is quite dangerous, especially for second stage / fine fuel filters, as you effectively introducing raw, unfiltered fluid into the system. You are actually just putting fuel (or oil) into the outlet of the filter, and so bypassing the filter altogether.

The fluid enters the filter under pressure through the holes on the perimeter of the base plate.

The "dirty" fluid then passes through the filter media where it is "cleaned". It then flows to the central tube and back into the engine through the usually threaded hollow centre mounting stud.

Whilst it may save you time when bleeding the system, it may cause a whole lot of pain if you then get blocked fuel injectors. There is no substitute, I'm afraid, for just doing the job properly!


Hope this helps!

Andy

[seacap]

I second what AndyDG just said.

I am experiencing a clogged injector right now. The injector is frozen in the head and will probably cost me about 1500 to repair (long story).

Had an experienced friend tell me most clogged injectors happen right after a change of the primary fuel filter (the one on the engine). Crap gets in it when you install the new one. A fleck of paint, piece of dust etc. Thats all it takes for a clog. my friend recommended nothing less than a surgical environment for a primary filter change.

My clog happened right after the primary filter change. I didn't fill the filter, just pumped fuel through.

[landonshaw]

Thank you for the informaiton. When I changed the filter, I took the long way. just put it in and hand pumped out the air. Thanks for correcting the thread! dave

[senormechanico]

Good advice.

I could tell you a story about resurfacing a watermaker pump at anchor in Mexico because of ONE grain of sand getting past the filter during changes.