20 hours later and the pressure is still at 15psi.

I will remove the thermostat and test before I order a head gasket. I still think it is a pressure problem not a heat problem. Any pressure caused by heat would have gone away when the engine cooled. By my observation, expansion due to heat accounted for no more than 5psi of the 20+ that developed on the last run.

I have a recipe for crow. I would love nothing more than to be having that for lunch today. To go, of course. Eating it while driving down the highway at 75 with all the coolant staying in it's proper containers.

__________________
Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO