Mark,

Informative, well-written post - thanks.

Now, re this:
Does it go beyond just contaminating the oil? I mean, what's bad for the oil is probably bad for the engine, right? The reason I ask is that I usually hit a long light about 1 minute after I leave work. I've started keying off, but I have mixed feelings about this - I don't want to shorten the life of the engine just to gain a couple tenths of FE. Is that fear warranted or am I worrying too much?

 

It's probably not warranted, as long as you keep in mind:

- If you're within your first 200-500 miles on the engine, I wouldn't do this, as I'd want the rings to complete seating in the cylinders, and you *might* have some contraction / expansion of the pistons / cylinder walls, *if* it were really, really cold outside (below 0F, and probably lower). Note the qualifiers 'might' and 'if'.

- You're not doing this every single trip you make in the car.

- You keep in mind that if you change the oil to compensate for this, you will be removing the 'bad' potential for the engine. Short trips raise the acid content in the oil, and don't let the condensation burn off completely - especially in cold weather.

- If you decide to run synoil in the car, you'll minimize the chances of this (although it will still break down the oil eventually). You'll also gain a little better FE, because the engine will have less friction. I've run synoil in my last two Hondas, since they specify 7500mi oil changes as of the last few years on the V6's (now up to 10K (!) on the 4-bangers), and it gives me peace of mind for that long of an interval. I've had oil analyses done, and they show a good amount of life left after that 7500mi interval, as well.

Besides this, we now have a 'maintenance minder' in our cars, complete with a calculated oil life indicator.

-If you only had a conventional 12V electrical system to start the car, *and* that 12V battery was marginal, you might have a problem restarting so soon after your initial start, as the alternator probably wouldn't have time to recharge the battery properly. But the IMA system (primarily) uses the traction battery to start the car, so no worries there.

-Finally, you made an investment in a Honda, who, in the opinion of more than a few authoritative sources, on a whole builds the most reliable mass-produced engines in the world (automotive or otherwise). Their engineering capabilities in this area are second to none, not only from a longevity standpoint, but also taking the aspects of FE and usable power into account.

Thus, if this were to cause harm to an engine - I'd be willing to take my chances with a Honda. Frankly, I'd worry more about the emissions controls and what they'd put out in increased emissions, over shortened engine longevity (I've never owned a 1.3L R13 before, but I've had a few Hondas before this one - and I've never ever had an engine fail - even on cars with over 200K miles on the clock. Do your maintenance, and the engine will run for 300K before your 1st rebuild


On an unrelated note, I'm starting to think I chose the wrong career - I keep running into people who laud my writing ability (appreciate the compliment, btw

 

Mark,
I appreciate your thoughtful and comprehensive answer.

It's been a warm January- having the heat off wasn't too bad most of the time. Still, once the Chicago winter really sets in, my FE is going to drop, because I'm going to resort to robbing that engine of some heat for me.

 

Thanks - I agree with all that you said, and I'll keep keying off (except maybe on those sub-zero days).

As far as synthetic oil, I have a '96 Pathfinder with 220k miles that's only had its (synthetic) oil changed twice a year (which works out of course to around 11-12k miles/chg), and I'm still hypermiling with the thing. Even the Nissan service guy was impressed the last time he drove it. I doubt that's all due to the oil, but I've always used synthetics and I've never had a problem going at least 10k between changes. So I'm looking forward to putting synthetic in the HCH at first chance.

Thanks again for your time - keep up the good writing!