Hey guys,

I understand that overfilling the engine with oil will damage it. What I'm trying to figure out is just how much oil is too much. Let me explain...

I recently switched to Mobil 1 synthetic. (It's great oil, and is still crystal-clear after 1000 miles.) Just after I changed it, and checked it cold, the oil showed right at the top of the X's on the dipstick -- perfect. After about a month, though, the oil seems to be reading at just about the top of the H character itself -- i.e., overfull -- even when cold. I certainly haven't added oil, but somehow the oil level rose within a month. Of course, I check the oil everytime I refuel. The "process" is definitely a slow one, since I didn't realize the overage was real (i.e. wasn't just measurement error) until recently.

Now I'm pondering a) how this happened and b) if it's anything to worry about.

All I can figure for a) is that somehow my oil filter (K&N) has changed volume internally. As for b) I'm sure Honda has safety factors built into their dipstick, but I still don't know precisely how much is too much. It sure would seem weird to have to jack the car up to let a few ounces of oil drip out....

Any ideas?

- Warren

 

Warren,

Did you check the oil on both sides of the dipstick? It doesn't answer your question (only because I don't have an answer to it), but I've found that I have to look at both sides of the dipstick and take the "lesser" reading if I want accuracy.

Skip

 

if you have a little bit over, it should not do any damage.. if you have 2-3 qrts over, then HOUSTON WE HAVE A PROBLEM.. you might mess up your rings..

 

Testut,

Yup, both sides. Usually one side reads to the crossbar in the letter "H," and the other side reads to the top of the "H."

bayarea408,

I think I made it clear I was not 2-3 quarts over.

- Warren

 

I filled it, ran it for a few minutes, and checked it again -- and it was spot on.

Keep in mind this "oil raising process" took almost a month to get to the point where I even really noticed it! If I had overfilled it right from the beginning, logic would have me believe it would have always read high.

- Warren

 

The oil expansion phenomenon is usually due to what is known as "cavitation". Tiny air bubbles pool up in cavities, after the engine is turned off and oil cools, thus displacing small amounts of oil. The oil level appears to rise.....not to worry unless your 1/2 quart or more high. Over 1/2 quart or so will result in major cavitation.....air introduced in large volumes to the oil. This reduces the heat carrying capacity of the oil and thus premature break down of the lubricative properties of the oil occurs. The best example of cavitation I ever heard was: Remember when you were a kid playing in a pool? You drag your hand quickly under water and watch the bubbles rise.....this is cavitation in it's simplest form.

Utah

 

I've also heard if you don't drive a long distance the oil can collect enough junk (water, mostly) and the volume of the oil expands. A good drive of 20 miles or so will get things back to normal.

 

I don't believe the problem will be with the rings. Over filling an engine with oil will result in blown gaskets and seals. In other words, oil leaks will occur.

 

The oil expansion phenomenon is usually due to what is known as "cavitation". Tiny air bubbles pool up in cavities, after the engine is turned off and oil cools, thus displacing small amounts of oil. The oil level appears to rise.....not to worry unless your 1/2 quart or more high. Over 1/2 quart or so will result in major cavitation.....air introduced in large volumes to the oil. This reduces the heat carrying capacity of the oil and thus premature break down of the lubricative properties of the oil occurs. The best example of cavitation I ever heard was: Remember when you were a kid playing in a pool? You drag your hand quickly under water and watch the bubbles rise.....this is cavitation in it's simplest form.

If it is cavitation, wouldn't there be pitting in the engine? I suspect your car was not on an even surface when you changed your oil and therefore the reading was inaccurate.

Kaptain Insano

 

[QUOTE]Originally posted by chroot
[B]I filled it, ran it for a few minutes, and checked it again -- and it was spot on.

Keep in mind this "oil raising process" took almost a month to get to the point where I even really noticed it!