oil leak

Post by **poppet** » Fri Sep 28, 2007 9:22 pm

HI
We're having an oil leak problem. One that's continuous and steady from her dip stick - any ideas?
Thanks
Steve and Liz

Post by **MoggyTech** » Fri Sep 28, 2007 9:29 pm

Check crankcase ventilation system isn't blocked. If that's ok it sounds like compression blow back past the pistons forcing oil up the dipstick tube. Do a compression test as well.

Post by **Willie** » Sat Sep 29, 2007 12:59 pm

You would appear to have a problem with your engine breathing system.
do you have the type which has a rubber tube from the rocker box to the Air Filter or a pipe which feeds into the actual CARB.? Or, worst of all, do you have a mushroom shaped assembly on the inlet manifold
with a spring clip on top?

Post by **bmcecosse** » Sat Sep 29, 2007 5:54 pm

Piston blow-bye is throwing the oil out past the dipstick - it should have a little seal on the stop washer ? When engine is hot and idling - take the oil filler cap off. If there is an obvious plume of fume - then there's the problem. As a temporary 'fix' it is possible to connect a breather diectly to the inlet manifold via a 1/8" diameter restrictor so the engine breathes it's own fumes - but the real answer is to either overhaul that engine - or swap it for a good one!

Post by **poppet** » Tue Oct 02, 2007 7:56 pm

Hi
Thanks for the responses - we're still investigating all possibilities.
Just a question:
If there was a 'blow-bye' could this occur without the plug(s) being fouled?
All the plugs remain in good condition and the right colour.
Thanks
Steve and Liz

Post by **bmcecosse** » Tue Oct 02, 2007 10:49 pm

Yes - could be - just pressure in the crankcase with fumes going past the piston rings.

Post by **poppet** » Wed Oct 03, 2007 7:57 am

Hi
Excuse our ignorance but where would the pressure in the crankcase come from?

Post by **alex_holden** » Wed Oct 03, 2007 8:13 am

From pressure in the cylinders leaking past the piston rings.

Post by **bmcecosse** » Wed Oct 03, 2007 9:55 am

Yep - gases can blown down past the rings if they are 'stuck' or worn. This causes oil to leak from just about everywhere on the engine - but usually also forces oil back up the bores leading to a v smokey engine. Simple test - hot engine at idle - take off oil filler cap. Plume of fume/smoke reveals all.

Post by **poppet** » Wed Oct 03, 2007 6:50 pm

mmmm... no plume or smoke

Post by **bmcecosse** » Wed Oct 03, 2007 7:20 pm

Excellent -your engine is in fair health. Check the little felt waher is on the dipstick.