The Type 2 Bus cooling system is a tricky topic, and depends on how you choose to use bus. I have used a lot of different designs and here are my observations, so far…
Quick answer:
- Front mount cools best but is difficult to install, expensive, and ruins the aesthetic.
- Engine bay provides best protection and easiest to install but least capacity to cool.
- Belly mount is a compromise between the above. Better airflow/more fluid than engine bay and easier to install than Front Mount but is susceptible to road debris and damage and still need to pay attention to temps in hot climates.
If cooling is the highest concern:
If you plan to rack up a lot of miles on the interstate, or tow in an extremely hot climate then there is no better cooling setup than the factory VW Front Mount radiator system. These systems were used on the water-cooled bus manufactured in Mexico until recently. If done right, this system doesn’t look too awful but I’ve seen radiators just bolted onto the front (Function over form was definitely the priority of that persons install). I have also seen radiators that look like spare tires that mount to the front and don’t look too bad. If you have a clean bus and you don’t want to ruin the classic aesthetic, read on…
If protection is the highest concern :
For my personal bus I used Engine Bay radiators since I backpack a lot and travel mostly on dirt roads and backroad highways - I needed protection more than anything (I have a front and rear mounted winch on my bus… that just shows you the crazy “roads” I go on). Of course you can travel on interstate in this setup, but with stock transmission gearing and a bus that’s fully loaded, you’ll have to pay closer attention to temps. Engine Bay Rad setup has the least fluid capacity and can have the least airflow but I personally value this style most for my needs. You can see a bit of a cooling system walkthrough here: "Street Fighter" Tour - 1973 VW Bus with Subaru Drivetrain
The Belly Mount is a compromise but works best for most:
I see most folks going with a Belly Mount setup as you don’t need to think about temperature as much (Desert climates still need to be conscious of temp as asphalt gets hot!!). Most folks go with a Belly Mount as the Front Mount is expensive, hard to get the factory VW parts, and requires cutting up the front of the bus. The Belly Mount is a compromise between the Front Mount and the Engine Bay setup - It’s easy to install and gets better cooling than Engine Bay due to more coolant and better airflow. The downside is that you have to be very conscious about road debris and high-center clearance if going on backcountry roads. This system doesn’t work for me, but it works for most other highway drivers. You can see one variety of Belly Mount Radiator system here: 73 Busaru With Belly Radiator and here's another: 1976 VW Bus Subaru 2.5L JDM engine conversion
Hopefully this is a helpful writeup for folks weighing the options for their conversions. In summary, there is no PERFECT setup, but between these three you’ll likely find what works best for you and just deal with the downsides.
Here are the funny names I ascribe to the common radiator setups: Belly-Scratcher (aka belly mount), Hot-Heads (aka engine bay), Pig-nose (front mount).