Yeah yeah yeah, it's the topic du jour ...
How would I get better gas mileage. Should I let the engine idle for 3 -5 minutes, while waiting for a school bus, after driving 1/2 mile after a cold start ?
I have an '06 Sienna. In the morning my commute begins by taking my 3rd grade son to his bus top, 1/2 mile away. Then I take his 4 y.o. brother to pre-school about 4 miles away. Then I drive about 10 miles to work.
I know about the cold start process of emission controls.
No. 1/2 mile is not long enough to get the engine, coolant, catalyst, and O2 sensor up to operating temperature and shutting off the engine starts the process over again.
Your morning commute should be getting warmer by now, unless you live up in mountains. Have you given any thought to using synthetic engine & transmision fluids? RH
I probably won't switch to synthetic. I run it in my 1.8liter Passat with a Turbo. With oil change intervals at 3,300 miles I see no reason.
"Charles" asked:
Ray O responds:
What does the catalyst have to do with this? Charles was asking about improving his gas mileage, not about minimizing emissions.
Besides, if 1/2 mile of driving isn't enough to get the engine, coolant, etc., warmed up, wouldn't letting the engine idle during his brief stops be seen as desirable in that regard?
Geoff
You're correct - the catalyst does not have any effecd on fuel mileage.
Oops! In re-reading my response to the original post, I realized that it was not clear. My "no" response is to shutting off the engine, not letting the engine idle. The OP should let the engine idle and continue to warm up instead of shutting it down so early in the drive cycle.
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