Recently bought a 2003 Honda CR-V with 180k miles. Changed the oil this weekend and noticed a lot of blow by with the engine running and oil filler cap off. Is this indicative of serious wear or is it normal for these engines? Oil was pretty dark for the supposed miles on the change (1,000) but everything looks clean through the fill hole. Still trying to learn about Hondas, this is my first one. TIA
Honda K series engine "blow by"
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In my experience most 4 cylinders have a lot of "blow" out the valve cover when the cap is off. Is there any other indication where you think there is excessive blow by?
If you are super concerned maybe you can try doing a leakdown test. But chances are what you are experiencing is completely normal.
4 cylinders I have direct experience with that have a lot of "blow" with oil cap off
-2012 Regal GS 2.0 turbo
-2007 Camry 2.4
-2004 Honda Civic
-1998 Integra
-and plenty of others... Like I said, what you are experiencing could be completely normal and no cause for concern.
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Curious as how can you tell if an engine has blow-by while running it with the oil fill cap off. What takes place?
Originally Posted By: Tman220
In my experience most 4 cylinders have a lot of "blow" out the valve cover when the cap is off. Is there any other indication where you think there is
If you are super concerned maybe you can try doing a leakdown test. But chances are what you are experiencing is completely normal.
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Would excessive blow by also be evidenced with oil burning or a dropping oil level?
To be honest, I've never had my K24 Element running with the oil cap off, so I can't comment to whether it's normal at all.
I would do a compression test - dry followed by wet. If normal range, it is likely just a puffer ... If more that 10~15 PSI different dry to wet, you have ring issues ...
I would also do a serious ring soak to make sure they are free in the pistons to move as needed. I'd pull the plugs and shoot a big dose of Break-Free gun solvent in each cylinder. Let sit over night. Re-install plugs and drive it 25 miles with some hard accel/deccel like up/down a hill. Drain oil and change.
Less severe way, run full can BG109 (EPR) the last 100 miles of you oil change interval and then change oil and filter. Should do the trick.
If this is real blow-by, you will have oil consumption. So as it uses some oil, top up with MMO as long as you do not exceed 1 qt total. It will gently help on the way to the BG109 treatment.
Either hit it hard, or take the slow approach ... But I'm betting that it'll cut any oil consumption in half 
Unless you have broken rings or a partially destroyed piston ... A little puffing at idle is no big deal, but if it is really puffing hard, you have an issue. Imagine what is happening at speed with your foot in it ...
Me, I go straight at it. 180K is enough miles with unk service history that you could be experiencing stuck rings.
Unless you have broken rings or a partially destroyed piston ... A little puffing at idle is no big deal, but if it is really puffing hard, you have an issue. Imagine what is happening at speed with your foot in it ...
Me, I go straight at it. 180K is enough miles with unk service history that you could be experiencing stuck rings.
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If it isn't using oil, and some of these guys do, I'd have no concerns.
If it is using oil, priority one would be to replace the PCV valve and is that doesn't fix things, then priority two would be a dose of Kreen.
These are typically long-lived engines, so see how oil consumption on this new to you machine.
An '03 would be a first year K24. These have stamped steel sumps with the oil filter mounted way up high in a PITA position.
Our '12 has an alloy sump with the filter mounted base up vertically next to it.
How easy!
Other than replacing the pcv valve with an oem unit, top it off with some Valvoline Maxlife Red bottle. It worked for me with a an F23 that starting using oil. So not sure if it was the pcv valve or the HM oil that did the trick. Only used a quart of the HM oil and caught the consumption early on. I was doing a fair amt of hwy driving at the time. Previous to topping off with Valvoline ML I topped off with a quart of Mobil 5000. After a 1500-2000 miles of hwy driving the car was down a qt again. Which is when I replaced the pcv valve and topped off with VRB. No more measurable consumption after that.
Originally Posted By: gregk24
I would say it is normal. My 2006 Accord with the K24a8 did that with the oil cap off. It used about half a quart of oil in between 3500 to 5000 miles.
Sounds like nothing to worry about because it might not be blow-by, just crankcase harmonics. Those 4 cyl engines have a long stroke and short rods, so there is always a rather large air displacement below the 2 opposing piston pairs every 180 degrees of crank rotation. Big excitement at the fill hole is just something that goes along with long-stroke 4's.
Why the short rods (and long stroke) are worth mentioning is because lower rod-to-stroke length ratios impart a less-linear rate of piston acceleration/deceleration as it travels the bore. That just means that while the piston accelerates with an increasing rate from TDC, the rate of acceleration slows down mid-bore and then speeds up again around BDC and repeats. So compared to crankshaft degrees, the piston is getting more ahead of- and then falling behind the crankshaft at every stroke vs a longer rod. That means that the piston is not only accelerating and decelerating, but it's rate of acceleration in a single stroke speeds up and slows down again. So in addition to there being 1.2L of displacement whacking back and forth under the piston pairs, there also becomes a secondary pressure harmonic in the crankcase centered around the irregular rate of piston acceleration.
Contrarily, a longer rod and/or shorter stroke exhibits a more sinusoidal rate of accel/decel, without the brief inversion of piston acceleration rate exhibited by the K24, and all other short rod 4 cyl engines.
Basically it's normal for the engine design to have such excitement at the fill hole. If you really investigated, you might discover that it's just a low frequency harmonic, rather than a significant exodus of crankcase gasses.
You can see how Rod to stroke length ratio affects piston acceleration, the K24 in question would be very close to the blue line.
Its normal for the K24 engine. Its part of its emissions system.
I would check the rocker cover vent tube, it may be partially clogged.
I would not say it's normal for 4 cylinder engines. Maybe for Honda engines, but my Mazda 3 doesn't do it and my Ford Focus didn't do it. I don't know if my old Accord did it or others since I never checked.
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