Since developing an oil leak on my '87 240 a couple months ago, I have been reading BrickBoard about excess internal engine pressure. The leak is from the front onto the plastic shroud. Neither the valve cover nor pan show sings of significant leakage. I cleaned both hoses from flame trap to ntake manifold (both small hose and manifold nipple were plugged). I cleaned flame trap which was somewhat restricted. I can readily blow my breath through oil separator box with a hose attached to flame trap (as long as oil filler cap is removed). The oil leak has not subsided and the filler cap still "jiggles" during the "cap test". Is there anything else I can do to reduce internal pressure. Once front seals start leaking due to internal pressure, do they continue to leak even if pressure is reduced? Its time for me to replace the timing belt during which I will replace these seals, but I'd like to wait until this coming Spring. I am monitoring the oil to make sure it doesn't fall too low. Would switching to 20W50 oil for a few months make any difference?