How air cooling works on your air cooled Vanagon.

[mightyart]

The system for keeping your Vanagon engine running within the correct heat range is much more complex then most people realize. Learning how the system works will greatly increase your chances of getting as much life out the engine as possible. The engine itself is covered by steel "duct work" or "tin" which directs the flow of cooling air around the heads and cylinders and out the bottom of the engine.

Cool air enters the van through the big vents at the top, rear of the van.
Blue arrows are cool air, red arrows are hot air from engine exiting.

Cool air enters the air box from the sides, stays on top of the tin and then enters the fan.

The fan pushes the cool air into the ducts and over the flaps, and between the fins on the cylinders and heads.

As the cool air passes over and through the fins the heats is transferred to the air and the air is heated, the hot air then travels down and around to the bottom of the engine.

The heat is transfered from the engine to the air by the use of fins.

The hot air is then blown out the bottom of the engine, All the tin is important, the path that the air takes was designed for the best cooling.

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Nice pics. Very informative.

thanks!

[Volksaholic]

Very good writeup and pics! What a great service to all Aircooled Vanagon owners.

I don't have aircooled Vanagon experience, but the engine is basically the same as the '72 and up Bay Window busses. Based on my experience with those (and to a lesser degree with the old splitties) I have a couple things to add. After years of building and running Type 1 engines and then getting into Type 4 engines, I was very impressed with the redesign of the cooling air flow. The fan and fan housing are more efficient, all the cooling tin is tighter, and the airflow is very well regulated and well thought out.

Make sure you've got a good engine compartment seal. The Bays and I'm sure the Vanagons will run really hot if the seal is damaged... especially back by where the cooling fan will draw hot air directly off the muffler and recycle the heated cooling air. Keeping the rubber seals on the spark plug wires and such in good shape is a good idea. I was a stickler for spraying the oil and dirt off the bottom of the engine on my aircooled cars so the crankcase cooling fins can do their job. It also makes oil changes and other maintenance much more pleasant.

Lastly... see the little thermostat bellows in MightyArt's last pic? Make sure it's in good working order and the cable and flaps work smoothly... it's there for a reason. You want the engine to get up to temperature properly by blocking the airflow, but you want full airflow after that.

[bigdood]

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"We should all be having more fun. A lot more of the time. " -Randy in Maine

[mightyart]

Now it's fixed.

[Wildthings]

You mean that all those people who over the years have told me that VW's don't have cooling systems are wrong??? I thought all that tin was just to give the mice some privacy.

Nice write up, people need to understand how these things are supposed to work. IIHO the T4 cooling system works very well when its all there and well sealed.

[surfinwesty]

That example of air cooling on the VW bus is the best I have seen/heard from anyone...including all the mechanics I have talked too.

Bravo...Bravo
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Current Love:
"Adobe" 1984 VW Westy w/Subi

Retired:
"Swell Chaser #1" 1980 Westy (in VW Heaven)
"Swell Chaser #2" 1981 Westy (sold to loving family on TheSamba forum)

[AndyBees]

One thing I did with my 2.0 AC engine was use a slimmer and a little longer oil filter, Fram PH2870A. That filter fits the older Rabbit and Dasher gasser engines.

IMO the slimmer filter allowed more room for hot air to exit past it. Also, that filter is much easier to install and remove.

I agree with the engine seal.

Also, if your AC has A/C, most likely it's a dealer add-on and the tin re-work was not done properly, thus allowing hot air to enter the engine compartment from below. Make sure all those slits/cracks/holes/crevices are sealed (RTV high temp sealer works great).
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'84 Vanagon Tin-top, ALH TDI, two trips to Alaska, 2014 & 16. 1989 Tin-top unmolested.
1983 Air-cool, 225k miles, 180k miles mine, seven trips to Alaska from 1986 thru 2003. 1975 Bay hopeful.

[VanMan14]

I might be ending up with an engineless 1987 vanagon, would it be possible to put in an aircooled engine from a 80?

[surfinwesty]

I have an extra 2.1 water cooled engine that I can get rid of for cheap. I pulled it out of a van that is getting a new modified engine. I am also getting new head gaskets put on it so it will be good for at least for another 150k.

The mechanic I am using could probably do the install it with the engine cost for around $1500.
_________________
Current Love:
"Adobe" 1984 VW Westy w/Subi

Retired:
"Swell Chaser #1" 1980 Westy (in VW Heaven)
"Swell Chaser #2" 1981 Westy (sold to loving family on TheSamba forum)

[VanMan14]

I was thinking more along the lines of trying to install it as a project, i was more wondering if it would work and if there would be any issues
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1974 Super Beetle
1968 Magicwagen

[redtail]

Awesome write-up!

So the unobtanium alternator boot - what exactly does that do? I jury-rigged a dryer hose on there as my boot was torn to shreads. Is the boot only for passenger compartment heat or is that boot used for engine cooling as well?

[mightyart]