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Discussion Starter #1
I've seen this addressed but couldn't find it in search so will ask. My wife got an 05 Prius recently. We love it of course. She tends to be a driver who immediately after starting her car, puts it in gear and goes. I have always cautioned her to let the car idle for 5-10 seconds so oil can circulate first. How does this work in the Prius since the motor kicks on suddenly from electric idle and first few mph....is there some way the engine is pre-lubricated or is it just, bam....engine on? Thanks
 

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You will receive a lot of posts on this. The engine is spun up to 1,000 rpm by the smaller of the two electric motors which help power the car. At this RPM there is full oil pressure. Even at the 1,000 rpm speed only two of the four cylinders get fuel and spark so there is very little energy used in starting. Thats why there is long engine life even with constant starting and stoppings. There is no separate 12 volt starter on this engine. It has a completely different power stroke pattern than a normal gas engine and is built to supplement the two electric engines to drive the car. The engine runs to supply battery charge and to "help" supply additional horsepower to run car. It also runs to keep coolant and catalytic converter up to temperature for emission purposes. To help this along everytime engine is shut down for a length of time the coolant is pumped into a thermal reservoir holding tank located in drivers side front of engine compartment. When you shut down car you will hear noise from under hood which is not the A/C cooling fan but the electric pump which is transferring engine coolant from engine to thermous holding tank. (Supposedly able to retain engine temp coolant at temp for nine hours?) One other point. There is no absolute way of knowing if "ICE" is running. The "MFD" display only indicates if it is supplying something. Coasting down hill it can be running to keep coolant temp up with no indication. (just one example, there are many) Just for "curiousty" sake it would have been nice for Totota to have included a small light that would be illuminated when engine was running. Understand there is a source in Japan for an after market light but so far nothing posted in English. As far as I have ascertained there is absolutely no time that the "ICE" is the only power supplied to the drive train
 

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Regardless of what happens on the Prius, for ANY modern car, there is no reason to idle for 5-10 minutes. It's just as stressful to idle as to drive. (And while idling, you're not doing anything productive.) Waiting 5-10 minutes just wastes gas and creates pollution. (Although I do have to admit to doing it on very cold mornings, but that's more to warm up the interior than the engine.) The engine will warm up (and build oil pressure) faster when it's running at higher RPMs anyway.

Plus, the Car Talk guys say it's a bad idea. :)
 
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