Is the valve in the oil pump housing a check valve, or a pressure relief valve? Does it sit in the engine block right behind the check valve in the oil filter housing? (The mechanic who replaced the oil filter check valve on my car said he saw another one in the engine right behind the oil filter housing, after he removed the oil filter housing from the engine. It made me wonder if it was accessible from outside the engine block.)
How did it affect your oil pressure? Does your car idle with more pressure now when it's hot?
1995 E320 Wagon Moonstone Grey/Parchment 106K mi.
2007 E63 AMG Graphite/designo 75K mi