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Discussion Starter #1
2015 : 76k on the meter ..

Starting to notice heavy while vapor trails coming out of the exhaust ... jump the rpm's while in park and it becomes a white cloud then goes away... the boss thought it may be condensation in the tail pipes ..but at the 76 F outside ..that shouldn't be happening ...

What were some of the symptoms of a failed piston ring ?
 

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Do the vapor trails subside after your Pilot is warmed up?
Has the coolant level been dropping?
 

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Does the vapor trail smell sweet, like cooked coolant?
 

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Discussion Starter #4
Do the vapor trails subside after your Pilot is warmed up?
Has the coolant level been dropping?
No it still continues after the Pilot is fully warmed up .....I also have noticed that I topped off the coolant when I did my oil change little while back..thought nothing of it...

Does the vapor trail smell sweet, like cooked coolant?
kinda but i wasn't gonna stick my beard into the exhaust I would be smelling that all day :p LOL
 

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White exhaust is from moisture (coolant or condensation) or oil. If it's coolant, it's coming from the cooling system and you'll notice the level dropping. Condensation as a cause will go away as the exhaust system heats up. Coolant fog doesn't go away as you drive, although the fog may get thinner to the point you don't notice it while driving. It's down there at the tailpipe after all. If it's coolant, you'll see the loss in the reservoir and the radiator.

Oil finding its way into the combustion chambers makes smoke that doesn't go away as the engine warms up. Engine oil level will go down over the miles. Oil also fouls catalytic converters, making full recovery even more expensive if left to be. Oil burns to a white smoke rather than a cloud that dissipates by evaporation.

Golftango's question about what the plugs look like is a good one. Plugs washed with coolant are pretty darn white. They are steam cleaned by coolant leaking into the combustion chamber. Maybe from a blown head gasket. Oil contamination shows up as oil deposits and ash on the plug tips, typically dark to black and wet.


Head gasket failures that include coolant leakage into the combustion chambers can be diagnosed with a coolant additive that changes color in the presence of combustion gasses. These failures have combustion gasses in the coolant while the engine is running. On shutdown, combustion pressures go away, while residual pressure in the still-hot cooling system forces its way back into the combustion chamber.


Glycol coolants "burn" to a fog with a sickly-sweet fragrance. If you choose not to stick your face down to the pipe outlet, sacrifice a couple paper towels to hold over the tailpipe for a bit soon after you start the car. The catalysts heat up within a few minutes, during which time you'll be watching to see if it's steam or smoke, and then using the towels to capture the essence of the fog or smoke coming out. Then your nose to the towel will tell you quickly if it's coolant or oil.
 

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Discussion Starter #7

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Just looking in the mirror it's hard to tell the difference. The sniff test, using a paper towel as a smell accumulator, avoids the annoying tail-pipe lip burns. But yes, a close visual inspection is often enough if there are clouds at idle. Oil smoke that's related to piston/ring wear or from valve seals/guides is most prominent on trailing throttle. From a broken ring or cylinder damage, it can be more continuous.

There's no real substitute for experience. Coolant and oil each have very specific smells associated with them. Hard to share nose guidance beyond the 'sweet smell of coolant' vapor or the acrid fragrance of burned oil in the exhaust. Normal 'condensation fog in cold-exhaust system wisps' tends to have it's own specific smell too, but only until the catalysts warm up. Between then and when the muffler temps go above 100º or so is about the only time you get to see more than a thin wisp of clean condensing steam from the tailpipes.
 

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Discussion Starter #10
I will tackle the plugs when the rain goes away it's been here for a few days now ... Also while driving on the highway when I go to step on the gas to pass someone I can see out of my rear view mirror a cloud of smoke out of both pipes ... enough to notice then it disappears ... hope its not a ring job at this point :)
 

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Oil usage would be a key indicator. Spark plug color is the best for isolating the problem to specific cylinders. As a plug gets fouled enough to start misfiring, you'll be getting error codes and the MIL (check engine light).

Honda has extended the warranty for engine issues associated with a known piston ring alignment issue during engine assembly.


If it were mine and not covered by warranty, a fouled plug would start a specific diagnostic effort, starting with a compression test. Then a cylinder leakdown test with an ear to the intake, exhaust, and oil-filler cap to hear where air is leaking. Leaking rings leak into the crankcase, so listening for leaking air at the filler cap helps identify the specific leak that Honda has defined for us.

There is a similar broken-rings issue linked to cylinder detonation damage around VCM and oil ingestion into cylinders while VCM is engaged.


For those playing along at home, particularly those who still allow VCM operation: A good synthetic oil dramatically reduces detonation and subsequent piston ring damage. When VCM is engaged, the valves are deactivated for the affected cylinder in a particular order, so that the disabled cylinder is under vacuum most of the rotation. There's a tendency to leave oil on the cylinder walls with worn rings and pistons. When fuel is added and valve action is restored as the cylinder is reactivated, the oil is burned with the fuel charge. The oil burns a lot faster than the fuel alone would, and that's the detonation that further damages pistons and rings. Then more oil is left on the wall, and the problem snowballs. Good synthetic oil is much less prone to causing detonation when burned with the fuel. A good two-pronged defense is the synthetic oil, along with the VCMuzzler or similar to keep the ECM from dropping cylinders. These are preventive measures, but not curative; they won't solve a problem that's already manifest itself.
 

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Discussion Starter #12
Oil usage would be a key indicator. Spark plug color is the best for isolating the problem to specific cylinders. As a plug gets fouled enough to start misfiring, you'll be getting error codes and the MIL (check engine light).

Honda has extended the warranty for engine issues associated with a known piston ring alignment issue during engine assembly.


If it were mine and not covered by warranty, a fouled plug would start a specific diagnostic effort, starting with a compression test. Then a cylinder leakdown test with an ear to the intake, exhaust, and oil-filler cap to hear where air is leaking. Leaking rings leak into the crankcase, so listening for leaking air at the filler cap helps identify the specific leak that Honda has defined for us.

There is a similar broken-rings issue linked to cylinder detonation damage around VCM and oil ingestion into cylinders while VCM is engaged.


For those playing along at home, particularly those who still allow VCM operation: A good synthetic oil dramatically reduces detonation and subsequent piston ring damage. When VCM is engaged, the valves are deactivated for the affected cylinder in a particular order, so that the disabled cylinder is under vacuum most of the rotation. There's a tendency to leave oil on the cylinder walls with worn rings and pistons. When fuel is added and valve action is restored as the cylinder is reactivated, the oil is burned with the fuel charge. The oil burns a lot faster than the fuel alone would, and that's the detonation that further damages pistons and rings. Then more oil is left on the wall, and the problem snowballs. Good synthetic oil is much less prone to causing detonation when burned with the fuel. A good two-pronged defense is the synthetic oil, along with the VCMuzzler or similar to keep the ECM from dropping cylinders. These are preventive measures, but not curative; they won't solve a problem that's already manifest itself.

Agreed still waiting for the rain to give ... this pilot has a 110 k bumper to bumper extended warranty helps when you have someone that works for the H ... 1 owner I had been using mobile 1 full synthetic with an oem filter (MY own preference and discount) since i brought her home and the VCM attached ..hopefully I was doing the "right thing"

Hopefully it's not something major if you remember a while back I posted a piston slap noise so i'm wondering now if those two are related.
 
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