By Lance Plahn
I believe we should fit an engine overheating warning device, in order to prevent such an occurrence to extend engine life. After all water cooled vehicles have either a light on the dash or a temperature gauge. So I fit an oil temperature gauge, because they are cheap and easy to install. This then creates problems, with owners requesting to know what is a safe temperature. (It then takes me 2 hours to explain) The gauge is fitted as a trend monitor, not a precision instrument for R&D. So forget the argument about gauge accuracy and best location and type. (The gauge does not even require numbers - some water-cooled temperature gauges don't have them) The next problem is people trying too hard to get oil temperatures down, i.e. oil cooler's, when they should be trying to get head temperatures down, i.e. fitting scoops, tuning etc which cools the engine and shows on the oil temperature gauge. After all 90% of engine work I have done are head related i.e. cracked heads, burnt valves, leaking heads. Very little engine work is done due to oil related problems, sure when bearing life is used up and you have little or no oil pressure there is problems, but after all the engine is usually due for an overhaul.
The type 4 engine is a great engine, more suited to work in a Kombi than say a 1600, but engine life does depend on three main things.
• How the engine is built.
• How the engine is serviced.
• How the vehicle is driven
Neglect in one area can result in premature engine life.
How the Engine is Built.
This is a book in its own right and indeed plenty have been written, but some main points
are.
• Use quality parts when overhauling heads i.e. genuine valves and springs. (cheap valves and second hand springs do not go the distance. That's why genuine are more expensive) Always check spring specification with factory recommendations.
• Do not increase compression ratio, always check when overhauling engines.
• All tin ware must be fitted and sitting and sealing correctly. (why do repairers leave it off - after all you would not intentionally leave a radiator cap off) If necessary fit new exhaust heat shields. (between muffler and tin ware below fan intake) As this piece of tinware does wear out.
• Correctly tune. When engine life is used up we often forget that the carburettors and distributor is also worn out. Many distributors over advance, requiring re-working to factory specifications as set out in shop manuals. (009's do not meet type 4 requirements) Correctly set up carburettors or injection systems, this will require a gas analyser. On carburetted engines ensure the throttle shafts bushes are not worn and it is obtaining full throttle. It is interesting to note that injected engines last longer, mainly due to their ability to offer the correct air fuel ratio all the way through the rev range.
How the Engine is Serviced.
Again, there are plenty of good book's covering this area but some points are often over
looked or forgotten. The four problem area's I see are when, what, how and oil.
How Often.
As per manufactures recommendations. But if non-genuine parts are used this could change
service intervals. I believe oil change, including filter and adjusting or checking valve
clearances every 3,000km.
When and What.
Adopt good workmanship procedures including safety. Before removing valve covers, clean
dirt from around this area to prevent entry into engine. Same with removing spark plugs.
Remember VW has an option on two different heat range spark plugs, depending on ambient
temperature. (Type 4 use a three quarter inch reach plug - all too often I remove half
inch reach plugs) On removal of air cleaners, cover up carbies. All too often you see an
air cleaner off and someone blowing off the brakes. Also ensure all air cleaner seals and
connections are in good order.
Oil.
Everyone has a favourite brand, for whatever reason, but with an oil temperature gauge
fitted you can try different brands while recording their temperature readings, as some
oils do run much cooler than others by as much as 10oc. VW does have
specifications on what oil should be used. A 20w50 oil is too thick to go though the oil
cooler, resulting in the oil increasing in temperature rather than realising temperature.
Cut an oil cooler in half and you will see what I mean. As a rule, oils suited for turbo's
are not suited to air-cooled VW's as the oil is designed to resist heat and cannot give
off heat at the oil cooler. In contradiction to what I just said, I use Castrol GTX2 oil
in my own Kombi, as I have found it to run the lowest temperature bar some really
expensive oils. Castrol GTX2 is friction modified (simply put, under a high powered
microscope oil looks like a circular saw blade, friction modified knocks of the tops and
fills in the valleys) which appears to help it through the oil cooler, though the oil runs
hot after approximately 3,000 Km necessitating changing. VW does not recommend engine oil
additives, but all additives I have used reduced oil temperature by 5-10oc.
How a Kombi is Driven.
A different technique must be adopted when driving an air-cooled Kombi, as opposed to the
technique used when driving a water-cooled vehicle. A water vehicle is prone to overheat
when used in stop start city driving, and extended periods of idling, as they require
large quantities of airflow through the radiator. A Kombi is well suited to stop start
conditions and idling, dare I say ideal for a city delivery van. However on the highway,
the further you put the accelerator down the bigger the fire in the combustion chamber,
requiring more air to cool it and driving faster is not the answer, backing off is.
When you come to a hill the natural instinct is to flatten the accelerator, but by the time you reach the top the oil temperature is through the roof and takes forever to come down. So when you see a hill, accelerate on the flat, hold the pedal steady and when speed drops off, back off on the throttle. Sure you will loose pace and probably have to down shift, but if done right the oil temperature will only slightly increase, and in turn you know the heads are not cooking.
How do you turn the engine off after it has reached operating temperature? If you just turn it off at operating temperature, the temperatures just increase. (all components) So I think about when I want to stop the engine, reducing speed some distance before hand, this reduces the oil temperature. When I pull in I allow the engine to idle and stabilise the temperatures, then shut the engine down. It helps if you have a slightly richer idle mixture. Sure the temperatures still go up but not through the roof.
In an attempt to improve engine life I regularly use an upper cylinder lubricant. VW did recommend it in the early days. Used regularly the upper cylinder lubricant (placed in the fuel) lubricates the valves and guides retarding wear, reducing the occurrence of worn guides, resulting in burnt valves. Regular use may carbon up the ports and chambers, but to-day there are plenty of products on the market to place in the fuel or trickle through the carburettor that solve this problem.
The Automotive after market is renowned for selling cures to problems, after all some business philosophy is to create a market, then fill their needs. I know many opinions do differ on automotive subjects, but that's why we have motor racing. As they say when the flag drops the lies stop.