View Full Version : fuel filter/water separator

14-11-03, 18:44
Probably a stupid question, but do you have to bleed the whole fuel system after draining the water from the filter? So far I've avoided it for fear of having to bleed the whole lot, which IMHO is somewhat of a chore. The Volvo Penta booklet is a bit vague on this point (MD21A). I've come across a lot of posts regarding the filter, but I missed the bit about bleeding. Anyone?

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14-11-03, 19:24
No. When you drain water down from the filter, it is replaced by fuel from the tank. Provided that no air gets into the filter, which it shouldn't, no need to bleed at all.

On most modern engines there is no need to bleed air anyway, it will return to the tank without causing any problems. Bleeding may be advisable if the engine won't start, to avoid considerable cranking, but otherwise it should cope.

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14-11-03, 21:17
It depends where the filter is fitted in relation to the tank, if below the fuel level, no, but if the tanks are in the bilge & the filter is above the tank top, say by the engine, removing the water will let air in, probably needing a blead through.

Some racor units have a non return valve, so the lid can be removed & the housing topped up with fuel , so a bleed is not required.

Hope that helps.

<hr width=100% size=1>David
<A target="_blank" HREF=http://www.euroboating.net>http://www.euroboating.net</A>

15-11-03, 09:20
Thanks. My engine is from 1977, and the filter is placed well above fuel level, the tank being in the bilge. Will try and see what happens, next time I detect any water. By the way, my tank has also got a sump to remove any condensation water, but I gets stuck every year. Any ideas on that?

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15-11-03, 22:01
Might be teaching grandmothers but dont forget to open the fuel cock when you are draining the water otherwise the fuel cannot get in to replace what you are taking out! My primary filter is also well above fuel level and I can drain water and change the element without bleeding.

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