02-07-2015, 03:45 PM
Everything was degreased but I didn't silicone the top. That could be a good shout. Thinking about the thermostat part; as the engine heats up the diesel switches to bypass so effectively gets colder and thicker so any air ingress would get worse. Will put inline filter in to confirm problem and then penny mod and silicone everything else as the standard filter is much bigger.