I've scattered a number of posts accross this forum over the last year about fuel dilution in my 2015 Honda CRV. Polaris Labs routinely reports dilution >5% despite a mostly-highway driving pattern. Discussions with my dealer and American Honda have been unproductive.
But, after too much wasted time and energy, based on other UOAs found here and there, I've concluded that this level of dilution is not uncommon with the K24W DI engine/CVT combination, so my car seems to be operating as intended. (As a side note, Blackstone seems to consistently underestimate high levels of fuel dilution compared to labs that use gas chromotography, frequently by 3 percentage points or more: what's of no consequence to Blackstone is a "red-flag" panic to a GC lab.)
During my time spent roaming the internet in search of a solution I did find that Honda has changed the coolant thermostat in 2016 models, upping the temperature by 9 degrees F. I understand that oil temperatures and coolant temperartures are closely related, at least outside of aggressive driving situations. So here are my two questions:
1) Would a 9 degree F increase in operating coolant temperature increase oil temperature enough to make a meanginful difference in the amount of fuel that would evaporate during normal driving conditions? In the case of my car, it seems dilution increases to a point of equilibrium. Maybe a small temperature increase would tip the scales and make this point lower?
2) Honda has apparently tuned the K24W engines to maximize fuel economy, perhaps at the expense of factors like fuel dilution. Given Honda probably can't reduce the cause of fuel dilution without affecting fuel economy, does it seem reasonable that increasing coolant temperature would be a logical response in its part to reduce the amount of fuel that remains in the engine oil?
Of course, Honda is very unlikely to admit there was an issue with 2015 and prior engines and will not issue a recall to replace thermostats in the million or so K24Ws out there. But I would be willing to pay to replace mine if it was even a partial solution.
Thanks for any thoughts.
Dan
But, after too much wasted time and energy, based on other UOAs found here and there, I've concluded that this level of dilution is not uncommon with the K24W DI engine/CVT combination, so my car seems to be operating as intended. (As a side note, Blackstone seems to consistently underestimate high levels of fuel dilution compared to labs that use gas chromotography, frequently by 3 percentage points or more: what's of no consequence to Blackstone is a "red-flag" panic to a GC lab.)
During my time spent roaming the internet in search of a solution I did find that Honda has changed the coolant thermostat in 2016 models, upping the temperature by 9 degrees F. I understand that oil temperatures and coolant temperartures are closely related, at least outside of aggressive driving situations. So here are my two questions:
1) Would a 9 degree F increase in operating coolant temperature increase oil temperature enough to make a meanginful difference in the amount of fuel that would evaporate during normal driving conditions? In the case of my car, it seems dilution increases to a point of equilibrium. Maybe a small temperature increase would tip the scales and make this point lower?
2) Honda has apparently tuned the K24W engines to maximize fuel economy, perhaps at the expense of factors like fuel dilution. Given Honda probably can't reduce the cause of fuel dilution without affecting fuel economy, does it seem reasonable that increasing coolant temperature would be a logical response in its part to reduce the amount of fuel that remains in the engine oil?
Of course, Honda is very unlikely to admit there was an issue with 2015 and prior engines and will not issue a recall to replace thermostats in the million or so K24Ws out there. But I would be willing to pay to replace mine if it was even a partial solution.
Thanks for any thoughts.
Dan
