First oil change —> overfilled?
#11
Re: First oil change —> overfilled?
SOMEWHERE there IS documentation – will check on insightcentral, cleanmpg, etc. when i have time – that even slight overfills cause significantly worse fuel economy. I am sure that I didn't dream this up.
#12
Re: First oil change —> overfilled?
When our dealership was doing the oil changes, and routinely dumping in 4.0 liters, the dipstick would show 1/4" to 3/8" over the full mark, that's facing the back of a garage with a slab that's canting slight down at the entrance. Dead level check would likely reveal it even a bit higher.
After one 4.0 liter (dealership) oil change I finally woke up: jacked up the front end myself, loosened the drain bolt, then gently allowed 0.8 liter to seep out. The metric spec. for oil change with filter change is 3.2 liter. I have a glass pint jar (held pickles or jam or something) with both metric and imperial gradations, accurate enough for this sort of thing. I re-torgue the drain bolt, lowered it back down and checked: oil level was spot-on the dipstick top mark.
Anyway, for the next few days I tried to pay attention to the car's behavior. My take: it seemed a little more willing to roll-on, kind of like putting on lower rolling resistance tires. Basically a lower oil level means the cranshaft has to do less sloshing through the oil at the bottom of the crank case.
For what it's worth: the sweet-spot is not even at the full line. The ideal is mid-way between the two marks, like any tolerance. You have a range, somewhere comfortably between the two extremes is the place to be. That said, one practicality: any engine tends to consume a little oil between changes. Considering this, I would move that initial sweet-spot to the 3/4 mark, to give a little cushion. Really: anywhere between half and full is good.
Finally, it's easily appreciated: the volumes we're discussing are pretty small. Anywhere up to a quart overfill, spread over the surface area of the crankshaft, doesn't the raise the oil level a lot. But the manufacturer designed the engine for a range of oil levels, why not exercise some care in staying within that range?
After one 4.0 liter (dealership) oil change I finally woke up: jacked up the front end myself, loosened the drain bolt, then gently allowed 0.8 liter to seep out. The metric spec. for oil change with filter change is 3.2 liter. I have a glass pint jar (held pickles or jam or something) with both metric and imperial gradations, accurate enough for this sort of thing. I re-torgue the drain bolt, lowered it back down and checked: oil level was spot-on the dipstick top mark.
Anyway, for the next few days I tried to pay attention to the car's behavior. My take: it seemed a little more willing to roll-on, kind of like putting on lower rolling resistance tires. Basically a lower oil level means the cranshaft has to do less sloshing through the oil at the bottom of the crank case.
For what it's worth: the sweet-spot is not even at the full line. The ideal is mid-way between the two marks, like any tolerance. You have a range, somewhere comfortably between the two extremes is the place to be. That said, one practicality: any engine tends to consume a little oil between changes. Considering this, I would move that initial sweet-spot to the 3/4 mark, to give a little cushion. Really: anywhere between half and full is good.
Finally, it's easily appreciated: the volumes we're discussing are pretty small. Anywhere up to a quart overfill, spread over the surface area of the crankshaft, doesn't the raise the oil level a lot. But the manufacturer designed the engine for a range of oil levels, why not exercise some care in staying within that range?
Last edited by Mendel Leisk; 06-27-2010 at 09:23 AM.
#13
Re: First oil change —> overfilled?
To be fair to the dealership:
I just did an oil & filter change (maintenance minder came on with wrench symbol), the first I've done with US quarts (Penzoil Platinum 0W20). I put in 3 quarts, then an extra 8 oz (1 cup). After running the engine a minute, shutting down, letting it settle, and then checking the oil level, it was slightly closer to the bottom mark than top. I added another 4 oz and re-checked, it's now at around 2/3 the way up from the bottom mark to top mark. Another 4~8 oz would put it at the top mark, but I left it as-is, would rather have it a little lower than top mark.
Bottom line, if they let the fluids drain very thoroughly, I don't think you would be much overfilled with 4 US quarts.
I just did an oil & filter change (maintenance minder came on with wrench symbol), the first I've done with US quarts (Penzoil Platinum 0W20). I put in 3 quarts, then an extra 8 oz (1 cup). After running the engine a minute, shutting down, letting it settle, and then checking the oil level, it was slightly closer to the bottom mark than top. I added another 4 oz and re-checked, it's now at around 2/3 the way up from the bottom mark to top mark. Another 4~8 oz would put it at the top mark, but I left it as-is, would rather have it a little lower than top mark.
Bottom line, if they let the fluids drain very thoroughly, I don't think you would be much overfilled with 4 US quarts.
#14
Re: First oil change —> overfilled?
Data since my first synthetic oil (over)fill: My fuel economy plummeted to a worst-ever 37.0 MPG, based on 470 miles of mostly-freeway driving. My lifetime average is over 42 MPG, so my MPGs significantly dropped following the oil change. Today I went back to the dealer and they drained oil from the drain plug. Now it is at the mid-point of the hi/low dipstick marks, instead of at the high-point. I'll give another report soon – so far, based on the 10 hilly miles from the dealership to my house, the results seem better, and encouraging.
#15
Re: First oil change —> overfilled?
Took my HCH back to the Honda dealer. They drained the excess oil, and gave me a free quart of Honda-brand synthetic 0W-20 oil as a souvenir. Result: First tank since adjusted, based on 322 miles, returned 45.62 MPG – nearly nine MPG better compared with the MPG achieved with similar driving when overfilled. Lesson learned.
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