The lower temp thermostat has no effect on mixture. At around 120F the ECU should into closed loop operation and the O2 sensor system will take over mixture control. The point I was trying to make is that if the system can’t maintain control then opening the thermostat at a lower temperature will not help. Sort of like if the AC in a house can't cool down to the thermostat set point turning it down further will not make the house any cooler or make it cool any faster. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Ken
Sent: Monday, February 15, 2016 4:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Cooling system questions

Amen to that. Theoretically, the engine should run richer. Which dilutes cylinder lubrication. I wonder if mileage suffers noticeably?  

Again I say, a new radiator always worked miracles for me. I never had any luck flushing the system. In fact, it made matters worse. 

Ken L.

-----Original Message-----

Someday I'll figure out what folks think they are actually fixing by doing this. When the weather gets hot and the engine loading is up there the t-stat opening too early won’t help anything. 

Dennis