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Education - What is a waterboxer engine found in 80's to 90's Vanagon
The early 80's vanagon's were air cooled. Between 83 and 84 model years the engines were converted to water-cooled. The uniqueness of this engine was it's low profile box shape, it didn't need to go in a deep engine compartment. Another feature thought to be good was "vibration cancellation". Since the cylinders are opposite each other, the forces of combustion cancel each other. BMW motorcycles employ these engines claiming that it causes a very smooth, "vibration free" ride. In VW's, the 1.9L water boxer with Digijet fuel-injection can be identified by engine code "DH" and is rated at 80 BHP. The 2.1L water boxer with Digifant fuel-injection can be identified by the engine code "MV" and is rated at 90 BHP
image courtesy of http://www.howstuffworks.com/
|Also, Subaru and
Porsche have been using them successfully for years. The boxer engine is a
decent design. Its major flaw in the Vanagon was the cooling system and
cooling leaks of the cylinder heads. In fact, if you look at the engine,
some of the parts are borrowed off the venerable old Type one beetle. The
valve rockers arms, valve covers and oil pump come off a 1600 bug motor.
The crank shaft has the same stroke as the type one and even the rod
bearings are from a beetle. You remember how reliable the old bug was?
There are many theories floating around as to why the heads fail. The most common is air getting into the system. The theory goes, because the engine uses different materials in its construction, the metals expands and contracts at different rates when heated and cooled. During this time, when at operating temperature, coolant is under pressure and then a vacuum created when it cools. During this time a small amount of air gets trapped under the head gasket. (which is basically an o-ring around the outside of the head) If you look at the engine the black rubber gasket between the engine block and the head is the gasket that holds in the coolant. So over time, the air interacts with the moister under the gasket and corrodes the cylinder head, leading to coolant leaks. If you get this type of coolant leak, its not a stop driving event. You can try some stop gap measures to stem the flow, Bars Leak and that type of engine stop leak will slow it down for a time. You can continue to drive the bus, its more of an environmental issue than anything. The damage is done. I drove my old Turtle Van for about 15K miles with a coolant leak. I would have to put about a 1/2 gallon of coolant in a week. But it was cheaper than replacing the heads. Eventually, I rebuilt the engine because it had 179K miles on it. Its my opinion that, because of its limited production numbers, VW never put the resources into finding a permanent solution to this problem. I was told they experimented with different RVT gasket material but never had any real long term solutions. In my travels, even regular maintenance doesn't prevent coolant leaks. I've seen people flush the system religiously and the engine started leaking at 60K miles. Then I've seen people don't do anything and they go 150K miles on the same coolant it left Germany with. If you have a solution, besides replacing the engine with one of those South African Jetta motors, lets hear from you. Good luck. -Jim
A little history and evolution of VW Bus and Van engines
1980-1983 Vanagons were available with an air-cooled 2.0 Liter
4-cylinder gasoline engine or a 1.6 Liter in-line 4 cylinder diesel.
Sources used for the above information are:
Volkswagen Model Documentation by Joachim Kuch; http://www.bentleypublishers.com/product.htm?code=gvm1
Volkswagen Station Wagon/Bus Official Service Manual: 1968-1979 by Bentley Publishers; http://www.bentleypublishers.com/product.htm?code=v279
Volkswagen Vanagon Official Factory Repair Manual: 1980-1991 by Bentley Publishers; http://www.bentleypublishers.com/product.htm?code=vv91