GOOD OL’ DON. He’s the bloke who bought my rare-in-Oz 1976 VW 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 VWs 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 VW-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 gaskets on 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 VWs over the years so, yeah, I know what’s what with these happy, funny little air-cooled classics.

To cut a long story 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!

WHAT DO YOU RECKON? What brain-strain dramas have crappy replacement parts caused you? LET US KNOW AT uniquecars@bauertrader.com.au