I read a long time ago that downshifting is good for lubrication because the vacume pressure pulls oil into the upper end of the engine. Can anyone comment on this statement? Agree, disagree, is downshifting good or bad? Thanks, DH
quote:Amen-dear old dad told me that one time In a new vehicle I always try to get off of the gas periodically to get a little oil up into the ring area. And on long trips I do it periodically even on a broken in car. Probably a waste of time and effort.
Originally posted by TC: Trust the engineering that went into your engine's lubrication system to lube the valvetrain, as well as all other parts south of there. As far as slowing a car is concerned, one can either wear out $25 brake pads or a $3,000 clutch and transmission. I'll sacrifice the brake pads and spend the rest on beer!
quote:This part may be partially correct. The increased manifold vacuum with throttle closed will reverse load the piston rings - a good way to help seat the rings in a new or rebuilt engine. (That's why owners' manuals instruct not holding a steady speed during break-in.) But, going to the extreme of downshifts is unnecessary and could be harmful to both engine and clutch for the reasons listed previously. A drive thorugh hilly terrain, with the attendant frequent accelerator position changes, will accomplish the same thing without bugging the guy behind you on level freeway travel. As for manifold vacuum pulling "oil into the upper end of the engine", I'm not sure I'd agree with that. You have a full-pressure, pump-fed lubrication system that will supply ample oil volume to all moving parts of the engine.
Originally posted by DockHoliday: I read a long time ago that downshifting is good for lubrication because the vacume pressure pulls oil into the upper end of the engine.
quote:When I first got my licence in 1986, I read Robert Sikorsky's book "Break it in Right-Drive it Forever" and remember that trick on letting off the gas and coasting with new engines. I've done that quite a lot on every new car I've owned since then! And I've never had oil consumption issues on any car that I did that with.
Originally posted by Al: Amen-dear old dad told me that one time In a new vehicle I always try to get off of the gas periodically to get a little oil up into the ring area. And on long trips I do it periodically even on a broken in car. Probably a waste of time and effort.
quote:Yeah, we have a bunch of those around here too. It today's traffic, you seldom have an opportunity to leave it on cruise control for an hour. When you actually have the road to yourself, backing off on the gas about every hour may be a good idea.
Originally posted by DockHoliday: snip .... I take an off ramp which ends at a stop light that seems to always be red when I get there (I swear it sees me coming). snip ....