blow by/ vacuum at oil filler cap

Mitsubishi Delica L400 production commenced in 1994 -- After much anticipation, the L400 arrived on Canadian Soil in 2009!
sfd_656
Posts: 90
Joined: Mon Oct 24, 2011 12:33 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: l400
Location: kamloops

blow by/ vacuum at oil filler cap

Postby sfd_656 » Fri Nov 10, 2017 5:34 pm

I am shopping for a full sized pick up to put a camper on. The Delica is just too small for a family of 4 too sleep in and carry gear, it will remain as our daily driver and we still love it after 7yr and 150000km. In my research I've read about checking for blow by on the diesel trucks as a possible indication of excessive engine wear. I figured I would check if the delica had "excessive" blow-by as at 250k km shes probably got some wear and tear. not much blow by ver small puff of smoke when i removed the filler cap but i did notice a light vacuum on the cap when I pulled it off with the motor running. Anyone care to enlighten me on what causes the vacuum? is it normal? any other insights?

Thanks

sfd_656
Posts: 90
Joined: Mon Oct 24, 2011 12:33 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: l400
Location: kamloops

blow by/ vacuum at oil filler cap

Postby sfd_656 » Fri Nov 10, 2017 5:35 pm

p.s. shopping for a NA market vehicle has me feeling all warm and fuzzy again about our van, these things really are that good.

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Growlerbearnz
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Vehicle: Delica P25W
Location: New Zealand

blow by/ vacuum at oil filler cap

Postby Growlerbearnz » Fri Nov 10, 2017 6:11 pm

The vacuum is normal. The engine breather is connected to the intake pipe before the turbo, which creates a slight vacuum in the engine, preventing the engine from becoming pressurised and pushing oil past the seals.

That's how it works in theory, at least ;-).
Nothing says "poor workmanship" more than wrinkles in the duct tape.


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