Actually it’s 42.5 to 40.9.
OP’s earlier statement .
I doubt very much that you have any sludge build up on top of the head, it looks really clean for the age and miles. Now get a grip on the dipstick about an inch below the handle with one hand and the handle itself with the other and push together.
I see a hole in the plastic and I don’t see metal in that hole, and I think I should.
So you think he’s been putting in a pint too little all this time because the dipstick shifted? Maybe.
FYI
If a strong claim is going to be made about fuel economy, MPG is useless. Volume per distance is accurate - look up the MPG illusion.
… I dunno if this thread is ridiculous as sloepoke says - but I can’t look away!
Hello and thank you everyone, sorry for the delay in this response (1st week of school now over!). For those of you annoyed, I apologize. For those of you entertained, well … good.
@Tester: “I don’t know why you’re worried about plugged oil drain-back holes on the head? If that were the case, some of the oil would be trapped above the head and not drain back into the oil pan. That would cause the oil reading to be low and not high.”
Good point. I’ve never seen the inside of an engine up close and in person, but when I try to visualize it with this in mind, I realize you must be right. Maybe Keith is onto something with the dipstick …
@keith re: dipstick integrity - a false reading due to “dipstick failure” was an intriguing prospect, so I did as you suggested (firmly push metal into plastic handle) and found no play between metal and plastic whatsoever. BTW that hole in the plastic goes all the way through, dunno why, or why it’s even there. I suppose I could compare this dipstick with a new dipstick at a Honda parts dept. to be sure. Anyway, I’ve eliminated the dipstick option. I’m convinced it inserts the same distance as always.
Reviewing the responses here, that leaves 1) accidental use of filter smaller than OEM (thank you @NYBo; 2) oil pan dent (thank you @Tester); or 3) sludge layer in oil pan (thank you @insightful) . Since there is no obvious deformity of the oil pan, I’ll go with #1 until I can compare the current filter with a Honda filter, and if that’s not it, #3 until I can remove oil pan to verify.
New question: if there is a sludge layer, is there a way to 1) verify without removing the pan? 2) Remove the sludge without removing the pan?
Re: mileage and oil consumption - I offered that info because I didn’t know if it might be relevant to the overfill question.
I have reviewed my data re: oil consumption and discovered I am an unreliable narrator. I apologize. When I first noticed it in 2011 (first oil change after “overfill” started), my estimate was about 1/3 Qt per 10K miles . Detection of minor oil consumption started 10 months after the overfill issue began. My current estimate is about 1.5 Qt per 10K miles. That’s a big difference from what I originally stated, and clearly is significant of something. Again, I apologize for relaying inaccurate data.
Although I received a lot of good insight here (I will check compression and valve adjustment, and even though no code has been thrown, maybe even change the O2 sensors), I didn’t mean for fuel economy especially to become such a ridiculous distraction.
But since SOME readers were intrigued: There was no perceivable mileage drop correlating with the start of the overfill issue (Feb2011). There is a unequivocal mileage drop correlating exactly with buying new tires in July 2013.
2012: 42.8 m/g
Jan-June 2013: 42.7 m/g
July-Dec 2013: 40.6 m/g (tires: new set of 4 Michelin Defenders)
2014: 41.0 m/g
2015: 40.9 m/g
2016: 40.8 m/g (so far).
Maybe the tire thing is just an amazing coincidence. Those 90K mile tread tires now have 50K miles of wear. In 2013 Michelin Customer Service told me mileage would improve as the tires wore. The 2014 - Aug 2016 mileage numbers are pretty consistent, and not as good as the old tires.
I’d estimate that in terms of distance, my typical daily routine involves 30% city, 70% freeway. In terms of drive time, that probably converts to 65% city, 45% freeway.
So now you should all jump on me for providing wrong oil consumption numbers. Or ignore me. Either way, Thanks for all the insights and ideas.
Well, tires do have some effect on fuel economy, and based on the data you’ve given us, it appears you may have found the cause for that
The overwhelming majority of people would be thrilled to be getting your fuel economy, especially with a relatively old and high mileage vehicle
As I said earlier, the oil level on the dipstick always trumps the capacity listed in the owner’s manual. After draining the oil pan and replacing the filter, the actual amount required to bring the level on the stick up to max may be slightly less or more than what’s listed in the manual. I’ve seen this countless times, and there was nothing wrong with the vehicles
As I and others have already stated, I don’t think there’s a problem at all
The only thing I would recommend is getting the valve lash checked and adjusted, as the others have already stated
Continue to treat your car well, and it continue doing its job well, hopefully for some time to come
If I had to guess , my first guess would be difference in size of oil filters causing the discrepancy in the amount of oil a refill takes . At least one of my vehicles lists two different oil filters , the difference being the size of the filter . Either will work .
If you really wanted to know if there’s sludge in the oil pan , I would think you could drain the oil & use a bent piece of wire through the drain hole & dig around in there a little bit & see if you could drag some sludge to the hole or get sludge all over your wire .
@Sloepoke I was thinking the same thing. Wire, or a long, thin wooden dowel. Brand new and clean. Thanks.
Agree with a piece of wire to probe for sludge, but I’d be very surprised if you find any. You should not build up that much sludge in the span of one or two oil changes, that generally takes years of poor maintenance and I don’t think your maintenance program would cause that.
The OEM oil filter only held about a half quart of oil so an oil filter that holds 1/3 qt less would be about the size of a nickle so I doubt that is the issue. What ever happened is mechanical like a bump in the oil pan or something with the dipstick.
BTW, you are checking after starting the engine, right?
@Keith The process I use (I assume everyone uses, more or less) is this: run engine to operating temperature, shut off. Remove drain plug, drain oil, remove old filter. Wipe up the oil-on-block mess I just made removing the old filter, to minimize smoking. Install new filter to seal contact +3/4 turn. After dripping reaches reasonably slow rate (minimum 1/2 hour, sometimes longer), replace drain plug w/ new washer. Add 3 qts oil, idle engine for 5 minutes, shut off. Let sit for 5-10 minutes for drip-down, check dipstick. Until 2011 I could then add the last 0.7 qt and it would come up to Top/Full line. Now, it’s add 0.4-ish qt. I use individual quart bottles for the measuring scale on the side of the bottle. I assume those scales are accurate enough, but perhaps I have too much faith.
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I understood that this change was sudden, not a gradual change over the last 5 years. Could you clarify? Gradual could be sludge, sudden would be mechanical.
It doesn’t sound like you prime the filter before installing it
I suggest you start doing that
Some oil filters can’t be primed.
Because they’re installed horizontally, and not vertically.
Tester
I don’t understand the part about letting oil drip out for 30 minutes. Why that much time ?
30 minutes to let the oil drip out is pure insanity
No offense intended, but it IS insanity
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Allow me to indulge, I like this stuff:
“2012: 42.8 m/g
Jan-June 2013: 42.7 m/g
July-Dec 2013: 40.6 m/g (tires: new set of 4 Michelin Defenders)
2014: 41.0 m/g
2015: 40.9 m/g
2016: 40.8 m/g (so far).”
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42.7+40.6=41.65 for 2013
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What are the errors on the measurements? A 20% error for 2013 gives a spread of 8.33 in either direction. 10% would be 4.165. That means in order to claim 40.8 in 2016 is significantly different from 41.65 with, say, 95% confidence, both measurements would have to have an error way better than 10%. The numbers - written with an accuracy of three significant figures - are all within even 5% error (+/-2.082 mpg). This all assumes a linear relationship between the quantities.
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The quantity miles/gallon is a nonlinear function. I think - but I’d have to check - that means the quantities cannot be evaluated simply " by eye"… but I could be wrong.
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If the errors are better than 5%, or not… what is the technique?
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Other assumptions for fun:
• same gas station
• fuel dispensing mechanisms unchanged
• fuel grade unchanged
• fuel batches identical
• same temperature of fuel dispensed
• same driving habits
• tank filled from the same level each time
• fuel cutoff same
• driving route unchanged
• road conditions unchanged
• age of car components is comparable, e.g:
• air filter : clean every time
• alignment unchanged the whole time
• speeds driven
• extreme MPG-ing behavior
… etc. … in practice of course, that is all impossible to control for.
So just for kicks - in theory, no data : it could be something about the tires, the alignment of the wheels, … it could be worn components jostled by the new alignment, e.g. a nearly bad ball joint that was bumped into a different setting by the new alignment, sway bar adjusted differently during the new alignment, … fun to muse on.
But the mpg measurements as shown are meaningless to support any conclusion, including the claim that it is absolutely good fuel economy - without errors anyways.
@keith, The overfill change was detected in February 2011, but has remained consistent every oil change since then. Oil consumption has been a gradual change over time since then. The valve cover gasket had a minor leak (detected March 2016) and was replaced a mechanic (not me) when I had the timing belt, etc. changed in May.
@Tester is correct, this filter installs horizontally.
@JuniorMint, point taken (I assume the point is, the margin of error is potentially large enough to make the apparent changes in mileage insignificant). FYI 2013: Jan-June was 7672 miles on 174.468 gallons. July-Dec was 6706 miles on 165.252 miles. (I concede that the three decimal places to a thousandth of a gallon project an illusory degree of accuracy.)
I can think of other unaccounted-for variables to add to your list, e.g. passengers/cargo. Until 2016, I usually had zero passengers and zero cargo. Now I frequently have a 120-lb passenger and a 10-lb. purse, if you want to count the purse. I kid! The purse weighs only 5 lbs.
re: 30-minute drain – I started that after the overfill issue presented (am I possibly not draining it all out?, I initially wondered.). I don’t see what 30 minutes hurts. Maybe the phone rang. Maybe I eat a sandwich. Maybe I check email. It’s still dripping after 30 minutes.
I’ll visit a dealership parts department this week and ask if I can inspect a new dipstick and compare it directly with the current one. And I’ll take a closer look at the valve cover dipstick receiver hole, perhaps there’s been a change there.
I still think 30 minutes to drain is massive overkill
IMO . . . you should go out of the house, do your oil change, and don’t go back in until you’re done
Shouldn’t take that long, anyways, after you’ve set everything up . . . tools, jack and jackstands, as needed, drain tub, oil and oil filter, etc.
@db4690 Good advice, Thank you.