Kestas
Staff member
Thanks bruce, I'll take my superhero cape off now and relax.
Oil climbing dipstick
- Thread starter UncleRunkle
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If the oil is foaming, you might hear more valve train noise if your car has hydraulic lifters or lash adjusters. Those devices rely on the oil being incompressible, and foamy oil isn't. If your valve train is quieter, you probably don't have foam. It's probably quieter from the higher oil viscosity, rather than from any special properties of the additives.
Every car/motorcycle/truck/lawnmower engine I've ever had does this. I don't make a habit to "blend" oils or use additives (although I've just bought some LC to begin using). It's not true capillary action, as that needs...well...a capillary! It is a result of adhesion of the molecules to the surface of the dipstick. Water does this with the edge of a glass, as long as the glass is clean, because of the affinity of the water molecules to the glass. If you have a surfactant (surfactants reduce surface tension) on the glass, the water level will rise even higher on the edges, because the affinity of the water molecules to one another is not as strong as the affinity of the water molecules to the glass surface.
So, oils with good surfactant levels will creep up the stick. It's not cooling of the oil dipstick tube changing pressure enough to "suck" the oil up the dipstick.
edited for a typo
So, oils with good surfactant levels will creep up the stick. It's not cooling of the oil dipstick tube changing pressure enough to "suck" the oil up the dipstick.
edited for a typo
I am using 0W-30 Mobil 1 (just to get rid of the thick stuff) in my Toro mower. It has a straight 4 or 5 inch vertical tube and dip stick. You cannot just pull it out if left overnight and get a reading as it is always and inch or so up the stick. It definitely creeps up by capillary action.
This never happened with the Expedition running plain Pennzoil.
It could not be tested this way in the sports cars as the oils have to be tested hot. The sticks are wet and need to be wiped first.
This is an interesting feature and needs to be tested further.
aehaas
This never happened with the Expedition running plain Pennzoil.
It could not be tested this way in the sports cars as the oils have to be tested hot. The sticks are wet and need to be wiped first.
This is an interesting feature and needs to be tested further.
aehaas
Kestas
Staff member
If "creeping" is the mechanism we experience, then why does this happen only on certain makes and models? I use the same oil on all my cars, and all of them have flat-blade dipsticks. Why does the oil only creep up on some of the dipsticks? And if creeping TRULY was the mechanism, we should have collectively noticed this over the 100 years of car ownership, and this would be true across the board for every vehicle ever made.
I'll admit that oil does creep along surfaces, but not to the point that it leaves a sharp oil level indication higher up on the dipstick. I still say the air in the dipstick tube, contracts pulling the oil up.
[ April 15, 2006, 11:31 AM: Message edited by: Kestas ]
I'll admit that oil does creep along surfaces, but not to the point that it leaves a sharp oil level indication higher up on the dipstick. I still say the air in the dipstick tube, contracts pulling the oil up.
[ April 15, 2006, 11:31 AM: Message edited by: Kestas ]
Kestas, I see what you are saying...if the dipstick tube is submerged in oil so that the dipstick isn't hanging freely in the sump, and if the dipstick is sealed at the top. Easy enough to test: next time, pull your dipstick out just enough that it doesn't seal at the top. Next morning, pull it out and mark the level. Wipe it clean, and reinsert it to the same NOT SEALED position. I'll bet you it will be lower. It creeps up at night, sort of like the Indians in the old western movies!
Oh, forgot...the reason capillary action is so much greater than this creeping, is because to have true capillary action, the fluid needs to be surrounded more closely. This attraction of the fluid to the surroundings is magnified when the surroundings are so close.
The opposite of this fluid-to-surface attraction is easily observed with water on a waxed car. Surface tension is so high, water beads. Decrease the surface tension with a surfactant (soap), and the water flows along the surface, i.e., the bead of water breaks up.
If that doesn't make sense, Molakule could explain it to everyone's satisfaction, I'm certain. It's no big mystery....
The opposite of this fluid-to-surface attraction is easily observed with water on a waxed car. Surface tension is so high, water beads. Decrease the surface tension with a surfactant (soap), and the water flows along the surface, i.e., the bead of water breaks up.
If that doesn't make sense, Molakule could explain it to everyone's satisfaction, I'm certain. It's no big mystery....
My Bigblock Mopar engine manifold bolts go thru the intake manifold and screw into the head intake side. Oil is splashing all over the valve train area. The big block has a metal splash cover that fits below the manifold. However, if you don't put sealant on the bolt near the top 1 inch of the bolt....oil will climb out onto the outside of the manifold. Learned this the hard way.
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