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Posted by: VaccaRabite Aug 8 2021, 06:38 PM

So some of you may remember my thread a couple weeks back that the oil filler cap disappeared during a spirited drive a while back. I have 2 other caps, but they are the wrong size (grrrr).

I drove a couple times and not much oil came out, but a little did. So I figured some aluminum foil where the filler cap should be would keep the small amount of oil the comes out from happening.

So after applying some heavy duty foil, I fired her up and went for a drive for about an hour. Came back and the FOIL WAS NOW GONE! There was foil around the lip of the filler, but the foil the covered the opening has either been blown off, or sucked into the crank case.

So... yeahhhhhhhhhh.

Engine ran great. No changes to oil pressure or oil temps. Clearly I need to drain the oil out and also pull the tuna can off and look around.

So. How boned am I?

Zach

Posted by: BeatNavy Aug 8 2021, 06:44 PM

Zach, pretty sure intake is going to have vacuum (runners, manifold, throttle body, cylinders, etc.). The oil filler is part of the crank case. There you will have pressure from whatever blow-by you get. But hopefully not too much (or you'll have oil leaks everywhere).

Edit: point being, it most likely got blown off.

Posted by: wonkipop Aug 8 2021, 06:52 PM

most likely.

there is vacuum but its at the valve, hose to air cleaner inlet plenum to help draw the vapours into the induction side of engine.

better get yourself a new filler cap mate.

Posted by: Spoke Aug 8 2021, 06:54 PM

I would think the crankcase would be under pressure unless you have vacuum from the intake connected to the PCV. If you have a catch tank and filter, the crankcase would be under pressure at all times.

For the tinfoil cap, if it blew off I would think it would be jammed in the fan and likely squished together along some of the vanes as centrifugal force would flatten the foil against the vanes.

Posted by: SirAndy Aug 8 2021, 07:00 PM

Both, depending on the rpm ...

Posted by: VaccaRabite Aug 8 2021, 08:01 PM

I've got 3, but they are all the wrong size. I think (as in I saw it recently) I have a whole other filler neck I can put on that uses the size cap that I have a surplus of. I just need to find it and swap it over.

I'm still going to drain the oil and pull the tuna can just to inspect everything. But I tend to agree its probably sucked into the fan and blown over under the tins somewhere...

Zach

Posted by: SirAndy Aug 8 2021, 08:55 PM

To elaborate, on my 2056 i used to blow out the plugs for the head vents.

So i did some testing and at lower rpm <3k-ish the engine would suck in air through the head vents but above >3k-ish it would switch to blowing out air (and oil) from the same vents.

Posted by: Krieger Aug 8 2021, 11:26 PM

Cut your oil filter open and give a look.

Posted by: wonkipop Aug 9 2021, 04:46 AM

thats very useful empirical information.
nothing like facts.

i'm still laughing at the tin foil hat on the oil filler! sorry VaccaRabite - i do feel for you.
thats two things that have disappeared into the void. make sure its not three. its the third one you got to watch out for.