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R&D - Subaru Liberty/Outback Gen IV H6 3.0L EZ30 Aluminium Radiator

Updated: Dec 2, 2021

We all know how great the EZ30 engine is, but it doesn't come without (thanks Craig) some flaws. Mainly this is to do with overheating and cooling efficiently of the standard radiator. Because the actual depth of the engine, the distance between the engine and radiator/aircon assembly is quite tight. Therefore the thickness of the standard radiator is only 16mm. For the standard application, this is just adequate, once you add tune/exhaust/intake/turbo or supercharger and start leaning on the engine, the stock radiator is definitely out of its efficiency.

That is why we started to develop a performance replacement for this platform. Now as previously mentioned the room between engine and radiator assembly is very tight. In order to get the maximum efficiency and our research we decided that doubling the thickness to 32mm will still allow the great fitment without butchering the fans and overflow bottle, while still having great efficiency and get the best fitment. (See picture)

But isn't 40/50mm better than 32mm....????

Well, yes. Extra volume is always best. But the overall fitment and modification would be terrible and costly. Because of the increased thickness it would cause a high pressure zone behind the radiator, due to the distance between the engine and radiator/assembly is close. With such a high pressure zone there, the radiators efficiency to exchange heat would decrease because the air cannot escape. So increasing the thickness in this application would then decrease the performance of the radiator. That is why we choose to go with a 32mm. (See above picture)

Ok.....What about 1 row vs 2 row?

Well in order to use a 2 row core the minimum thickness is 38mm which as we spoke about probably wouldn't fit without major modification. Also the gains of volume a 32mm 1 row in compared to a 38mm 2 row is only marginally comparable, because there is a separation between the rows which means there would be the approximately the same amount of volume compared to these two core sizes. (See figure below). Much different if you were comparing a 32mm 1 row to a 44mm+ 2 row.

So over the next coming months we will be testing fitment as well as efficiency of the radiator. Check out our pictures:

Check website for more updates :)

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thomas ogden
thomas ogden
May 20

How does this oil cooler work? Is coolant supposed to go to a intercooler? Or is oil supposed to go to the radiator?

Jack M
Jack M
May 20
Replying to

The oil runs through the internal heat exchanger at the bottom with the brass fittings. If you’re using -AN fitting the thread and pitch is m14 1.5.

If you have the automatic transmission, the OEM hoses will fit straight into it.

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