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I once read that to check whether ur engine has gone past its half way mark you should lift the dipstick while its ideling and see if theres any air preasure there and if there is its past its half way mark. I just wanted know A. is this true and B Why is this true.
I've never heard that before, but I have a guess as to why that might be said. I have no idea if it's actually true though.
If the piston rings are leaking, the gases will pass into the crankcase, creating higher pressure. I think the PCV system is there to recirculate this gas into the intake, but I suppose it's possible you might also feel this pressure in the dipstick tube.
sounds like a bunch of hokey pokey BS to me. there is air in your crankcase anyhow. the heat from friction from the rotating assembly will cause the air to expand, thus creating pressure. not to mention the heat from the oil will also up the pressure, as will heat radiating past the pistons from combustion. if you pull the dipstick out, the increased pressure inside the crankcase is going to find the fastest, easiest way out that it can. and that would be through the dipstick. while i have never heard of this 'procedure' before, im willing to bet that you would get the same result from a brand new car as you would a 20 yeard old car once its up to operating pressure.
and redaztec, i think that you might be on to something with the worn rings. worn rings = lower compression because the rings leak. while this doesnt increase the pressure in the crankcase, a piston with good rings that is on its compression or exhause stroke will actually lower crankcase pressure. if air is leaking past the rings, the pressure might be more noticable than if the rings were good. its an interesting idea, possibly more research on this could be done. its lots of math, thats fa sho.
On my BMW I had an air suction sound that was pretty loud when I pulled the dipstick but it wasn't because of the engine being halfway dead, it was because the oil seperator valve died. Replaced it and voila, no suction.
I never heard of that, if air is coming out the dipstick tube, your pvc system clogged or not working right. There might be a slight pulse of air, but shouldn't be a lot out the dipstick tube. Most causes of serious crankcase air pressure is from the rings loosing air past them. A compression test & leak down test will confirm how far this 'halfway' mark is more than any other tests.
I know this is an old thread, but I just thought I'd test this theory. The amount of air coming out of the dipstick tube on my pampered RSX with 14K miles and my Accord (which was abused by the previous owner) with 221K is about the same (which isn't too terribly much in either case).
So, my thought is that this theory is false.
i've never heard that exact thing as being an engines half life. but indeed the presence of air comming from the dip stick hole would indicate that there is blow by caused by worn piston rings. but i'd say keep clean oil in there and you should be fine as long as you dont forget to change it fairly often. another trick is to lay a piece of paper over the dip stick hole while the engine is running. if it moves because of air pushing it off, there is excess amounts of blow by and worn rings. compression and leak down tests will determine the quality of sealing by the piston rings though and over all ability to ignite the fuel.
