DUMPED SUMP SYNDROME
GOOD OL’ DON. He’s the bloke who bought my rare-in-Oz 1976 V W Beetle Karmann Cabriolet a few years ago. Don has had a run of bad luck lately. Can you believe the poor fella had not one, but TWO of his V Ws catch fire in the space of less than a year? His Kombi pop-top camper burnt to the ground but thankfully six months later the fire damage to his V W-based beach buggy wasn’t quite so bad – it was repaired.
Don’s bad luck hasn’t spared the gorgeous Cabrio, either: one day a stiff breeze yanked the driver’s door from Don’s grasp as he opened it... it was hit by a bus.
More recently, oil leaks have caused Don some grief. Due to their design and layout, there are at least two dozen seals, joins and gasket son a VW air-cooled engine that are a potential oil leak. The engine’s eight pipe-like push-rod tubes are particularly prone as each has a seal at both ends; they drain oil from the heads to the sump, and are easily damaged. Don had a stickybeak underneath and sort-of guessed the push rod tubes was where the oil was escaping.
So Don replaced the eight standard pushrod tubes with aftermarket two-piece items. Trouble is, he installed them arse-about which meant, due to the seal design, oil draining from the heads couldn’t cascade back to the sump without leaking… Fed-up, Don’s next step was to take it to a mechanic who correctly re-installed the tubes.
But the oil leak became worse.
Despondent, Don called me for advice. I’ve rebuilt, refreshed, restored, recommissioned, wrecked and raced plenty of V Ws over the years so, yeah, I know what’s what with these happy, funny little air-cooled classics.
To cut a long stor y short, when discussing the engine and the work he’d paid for since buying it from me, Don mentioned that the oil filler unit had been damaged and replaced with a new one. Knowing what I know about these engines, I knew that the oil filler unit was part of the crank case ventilation system. I also knew higherspeed freeway driving causes more crank-case pressure… I began putting clues together: could the new plastic oil filler/breather unit be – indirectly – causing the oil leak?
We took a look, gave it a big rev and voila… oil spurted from the dip-stick hole. I removed the crank-case breather hose and when blowing through it – like blowing up a balloon - there was obvious restriction. I unbolted the new oil filler and instead of an 8-10mm breather hole, we found one the size of a match-head…
I drilled the breather hole to a decent size and the problem was solved: my old Cabrio no longer dumps its sump!