Plurging air from a looped system may be more difficult then returning air to a tank....but running all the way back to the tank is a waste of hose,filters, and valves. My Toyota came from the factory with a looped system and it really just makes sense.

I'm sure others on the forum will disagree with this and call me a luddite, but I opted for 4 ball valves (2 for supply/2 return) instead of 2 three way valves in my Ford b/c I just hate electrical.

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1975 Mercedes 240d (Daily driver, town)
1980 Toyota HJ45 (diesel) (Daily Driver, Farm Implement)