Engine oil-leaks

From: Nigel A. Skeet

As you have probably already discovered, being a classicist isn’t an ideal preparation, for 1968~79 VW Type 2 ownership, or indeed any car ownership!

I think most people associate the early Greek and Roman civilisations, as being the basis for the study of Classics, but there were several others in Asia, Africa, the Middle East, plus Central & South America. What aspects (e.g. languages, culture, architecture, music, sciences & mathematics, etc) of Classics are you involved?


A member had written in:

I hope you don’t mind me contacting you like this – I’m a member of the T2 owners’ club and drive a 1974 Westfalia, which I’ve had since 1998. I’m afraid I’m not sure which of the club’s officers gives technical advice – please say if you’re too busy or I should ask someone else – but I’ve seen your articles in the T2 magazine (which I’ve not now got with me – so I’m also not able to access the member’s area of the website), and wondered if I could get some advice.

The VWT2OC technical advisory panel (of which I have never been a member), seems to have dwindled in number, during the past few years. Mike Tout (Tel. 01 884 – 841 598), Bruce Hodson (Tel. 01 263 – 734 444) and Peter Good (Tel. 01 552 – 751 941) are the official technical advisors, but I am often contacted by members about a whole range of topics, owing to my high-profile presence in the magazine and on the website, plus various Internet VW forums.

For the past 1¼ years or so, I seem to have been writing most of Transporter Talk single handed, but that cannot continue for much longer. There is an URGENT need for VW Transporter related material, from a greater number of members.

The 1974 VW 16/1800 Type 2 Westfalia Continental campervan, seems to have been made in relatively small numbers and I have yet to see one “in the flesh” or featured in any VW magazines, such as VWC&C – Volkswagen Camper & Commercial, which has been published since 2000 (82 issues to date; initially quarterly, then bi-monthly and now monthly). The layout is somewhat different from that of 1972/73 VW 16/1700 Type 2 Westfalia Contintental campervans. I know for a fact, that David Eccles, editor of VWC&C, would be interested in featuring a 1974 VW 16/1800 Type 2 Westfalia Continental and its history (e.g. previous owners, acquisition, general use, travel, tales of woe).


A few years ago I had the engine rebuilt  – it was a Vege engine which the previous owner had had installed in around 1997. I also had the cylinders re-bored to a larger capacity – something I’ve subsequently regretted, as it took a few years, and a couple more complete rebuilds – to stop the engine from breaking down. The recurrent problem, as i understand it, was that the rebuilds didn’t include reinforced push-rods; since these have been installed, the engine has basically been running fine, and I’ve not had any problems. But I was so scarred by the catastrophic breakdowns (in several cases ruining family holidays), that I’ve not really dared to drive the van much.

You didn’t mention whether you have a 1974 VW 1600 Type 2 (VW Type 1 style engine) or a 1974 VW 1800 Type 2 (VW Type 4 style engine), which have different designs of flat-four air-cooled engine!?! From our telephone conversation during the weekend, I deduce that you have a VW Type 1 style engine, whose circular oil-strainer plate, is held in place by six 10 mm AF, M6 acorn-nuts.

Unless your rebuilt engine included an after-market high-lift camshaft and/or high-ratio rocker arms, opening the cylinder-head valves, ordinary factory-standard push-rods, should be quite adequate.

So far as you are aware, what is the displacement, stroke, cylinder bore and compression ratio of your current non-standard engine?

The factory-standard VW 1600 Type 2 engine (i.e. VW Type 1 Beetle style engine), has 1584 cm³ displacement, 69 mm stroke and 85.5 mm bore. After-market substitute cylinder barrels & pistons for this engine, typically have a “bore” of 87 mm, 88 mm,  90.5 mm, 92 mm or 94 mm, giving displacements of 1641 cm³, 1679 cm³, 1775 cm³, 1835 cm³ and 1915 cm³ respectively, when used in conjunction with the 69 mm stroke crankshaft. Unless the piston crowns are dished and/or the cylinder-head combustion-chamber volumes are enlarged, the compression ratio will have increased above the factory-standard 7.5 : 1.

The three largest bore sizes, require machining of the crankcase (and cylinder heads I think) to accommodate them, and should be avoided in my opinion. For a VW Type 1 style engine, 88 mm “bore” cylinder barrels & pistons, combined with a 76 mm stroke crankshaft, to give a 1849 cm³ displacement, is probably the most reliable way, to achieve an increase in power & torque.

Given that increased power, results in there being increased heat to be dissipated by the cooling system, I would recommend the substitution of the VW Type 4 style engine’s 7-row oil cooler, in place of the standard 5-row cooler (increasing oil-cooling capacity by about 40%), if this has not already been done. This would necessitate modifying the cooling-fan-housing’s oil-cooler “dog house” enclosure.

As a general rule, power & torque are increased by substituting a free-flowing extractor exhaust system and twin carburettors with separate inlet manifolds. The single-carburettor inlet manifold, severely restricts air flow, limiting the mass of air which can be inducted into the engine, which limits the available power.


Although i took the van to my local mechanic for a health check before setting out, I do seem to be getting through the engine oil at quite a fast rate – I had only got from Glasgow to Kendal (admittedly driving without stopping) before the oil light came on. 


The advice I’m seeking really concerns the oil level. Over the years I’ve constantly tried to get oil leaks minimized – and when they’ve been serious, regarded them as a sign that something is very wrong with the engine. I’ve never really managed to get clear advice from any of the people who have worked on the van as to whether this is correct or not.

Over the 600 or so miles I’ve done over the last few days (I made some detours), I’ve topped up about 1.5 litres of oil. The engine, as I say, seems to be running fine. But in the past, I’ve found having to check the oil before every long journey (and usually having to add some more) rather a worrying sign. it would be reassuring to know that if is just a fact of life!

Your VW air-cooled engine, should NOT be leaking and/or burning so much oil!

The Volkswagen factory,  regarded an oil-consumption rate (i.e. oil burned along with the petrol) of 1 litre per 1,000 km, as being “acceptable”, but this would be for a well-worn engine in my opinion.

If you are burning significant quantities of oil, the spark-plug electrodes and insulator noses inside the cylinder heads, are likely to be oily and exhaust smoke is likely to be black or blue in colour, especially when suddenly revving the engine and then quickly backing-off the throttle. It might be useful to undertake a compression test and/or leakdown test, to determine how well the valves and piston rings are sealing. A compression test can easily be done using a simple DIY compression tester but leak-down testing requires more specialised equipment.

Connecting a vacuum-pressure gauge to the inlet manifold, will also allow one to undertake some useful diagnostic checks, which helps to highlight worn valve guides, leaking valves, worn piston rings and other faults, as outlined in one of my recent articles in Transporter Talk, about supplementary instrumentation. Sadly, the illustration (63 mm x 42 mm) on Page 40 is far too small to be useful; having been originally of A4 size (298 mm x 210 mm), which should have been reduced to no smaller than A6 size (149 mm x 105 mm), but preferably A5 size (210 mm x 149 mm), if it was to provide any useful information.


Nigel A. Skeet, “Air-Cooled & Water-Cooled Volkswagens: The Case For Supplementary Instrumentation – Part 2”, Transporter Talk, Issue 125, November & December 2013 – Engine Inlet-Manifold Vacuum Pressure, Pages 40~42

Leakage via various paths, is yet another problem, which can be exacerbated if the crankcase is being pressurised, owing to worn cylinder-head valve guides or worn cylinder-barrel bores and/or piston rings. Excessive oil pressure owing to substitution of an “uprated” oil pump or incorrect oil-pressure relief or control valve springs, will tend to increase leakage rates.

Typical oil-leakage paths are:

(a) push-rod tubes & seals;

(b) cylinder-head rocker-cover gaskets;

(c) oil-strainer cover gaskets;

(d) oil seal at flywheel end of crankshaft – leaked oil drips from clutch housing;

(e) oil seal or oil-return screw & flinger-disc at pulley end of crankshaft;

(f) top of dipstick tube – associated with crankcase pressurisation;

(g) crankcase breather tube to air filter – associated with crankcase pressurisation;

(h) base of cylinder barrels close to crankcase – damaged crankcase, cylinder barrels or gasket rings;

(i) crankcase parting line owing to damaged  or contaminated crankcase abutting faces.

If your engine is leaking oil at an alarming rate, it needs to be properly investigated; preferably by first thoroughly cleaning the engine exterior and then observing all suspect areas of the engine whilst the engine is running; preferably with the vehicle elevated on ramps or a vehicle hoist. It might take a while for oil drips to form or oil mist to spray out from the disconnected crankcase breather, but this is the only reliable way of identifying leakage sources.

When my 1973 VW 1600 Type 2’s AD-series engine had worn valve guides, but minimal oil leakage, it burned about 1.0 litre of conventional multi-grade mineral oil per 1,000 miles or 1,600 km; which I considered excessive. When in circa 1986, I substituted Mobil 1 fully-synthetic 5W/50, API SF oil (has lower volatility and is more tolerant of elevated temperatures), the oil consumption rate decreased to circa 1.0 litre per 3,500 ± 500 miles.

However, after a couple of non-eventful summers, that’s changing; I am planning to go to Normandy in a couple of weeks time, and have just driven the van down from Glasgow to London. I broke the journey up, but did most of it on the motorways, going around 55-60 mph (though i think my speedometer could do with recalibrating – it’s always somewhat lower than the satnav, esp. at the higher end).

Owing to the legally acceptable speedometer-calibration tolerances, being plus 10% to minus 0% of the true value, vehicle speedometers typically read about 5% high, even when the correctly-sized tyres (i.e. 185 R14C or 185/80 R14C) are fitted to the factory-standard 14 x 5½J inch steel wheels. What wheel and tyre sizes do you have on the front and rear?

A speedometer reading which is lower than the true value, is illegal. If non-standard tyres have been fitted, it’s likely that both speedometer calibration and effective engine gearing will have changed. If you have after-market alloy wheels, there’s a high probability that both the wheels and tyres are of an inadequate load rating, for a heavily-laden campervan and the tyres which are typically fitted, result in a higher speedometer reading, than one would observe with the correctly-sized tyres.

A speed of 60 mph, is probably the absolute maximum which can reasonably be sustained by a VW 1600 Type 2 engine, but during hot summer weather like we’ve had recently, 50 mph might be more appropriate, if one wishes to avoid engine overheating and high oil-consumption rates, owing to increased oil volatility at elevated temperatures. What supplementary gauges do you have, if any, to monitor engine-oil temperature & pressure, plus cylinder-head temperature?

If you are travelling to France, make sure you have the necessary headlamp beam converters,  spare-bulbs kit, safety equipment kit (at least one approved-pattern warning triangle but preferably two, plus reflective waiscoats for driver and all passengers), tow rope, temporary emergency windscreen (if you have a zone-toughened windscreen) and alcohol breath-test kit. Exceeding speed limits by even 1 km/h, could result in hefty on-the-spot fines! Excessive speeding, can result in one’s vehicle being confiscated and auctioned-off to the highest bidder, so beware!!!

I trust you have invested in some good road maps (scale = 1 : 200,000 or 1 cm => 2 km) of Normandy, rather than relying upon a satellite navigation system.

Nigel A. Skeet, B.Sc., P.G.C.E., M.Sc., Pg.Dip., B.A.