mt6forlife

I've always heard that starting an engine is rough on it because the oil has all run down into the pan and its better to let it idle for a few minutes instead of turning it off and then back on. So how about these hybrid cars that kill the engine at a stoplight and start it up again when you go? Wouldn't that wear it out?

Python2121

i know its tough on the battery to start and stop it, not sure about the rest of the engine

Pure Adrenaline

iTrader: (2)

Yeah, every time you turn off the car, the oil stops circulating, and when you start the engine again, the oil takes time to circulate throughout the engine again. We're not talking like minutes, but there is a period of time when the engine is initially running without full protection of oil. If I'm going into a store or something just for a minute, then I leave it running. But that's only in neighborhoods I'm familiar with. Any other places, no way in hell. I don't want to get my car stolen.

ccannizz11

Turning off then on again..... bad for engine wear, good for gas mileage.

Leaving it running..... bad for gas mileage, good for engine wear.

As for the hybrid cars. there are always tradeoffs of some sort. whether it's less power with electrical, less acceleration or more engine wear. There is always something sacrificed in an effort to get better fuel economy.

RaviNJCLs

iTrader: (4)

Yeh, it's bad to turn it off and on. It is when the engine goes through the most damage, other than probably sustained driving at 120 mph or more. However, unless you do it about 10 times in an hour for a prolonged period of time, I think you'll be OK.

anothercls

In NJ it is a $3k fine for idling your car with no one in it for more than 2mins. I have heard it is bad for the engine, but that is what a car is for, to waste money and drive.

CL-Spell

it makes since that turning the engine on and off would not be good.

Honda's hybrid cars which includes the new Accord V6 hybrid, start and stop their engines. How do they prevent engine damage?

fender4

petro oil takes time to leave a surface, cold starts cause very minor wear on the bearing surface, warm engines have a film of oil still protecting the surfaces. Now if you use synthetic, it has been proven that it flows off the surfaces at a much slower rate therefore causing less damage. The amount of damage is measured at the submicron level, ie many years until it could ? cause a failure. Some engines using synthetic have shown almost no wear after over 200k miles. Use Amsoil, this is what they preach.

ccannizz11

It's not "damage" really. I mean, I don't think I'm actually damaging my car every morning when I start it up. But it does wear on the engine, seals, and piston rings. eventually it might cause damage, but it would take a lot.

I assume the hybrids slow down the process of wear by using a high viscosity oil that doesn't drain into the pan too fast, so when stopped at a light and the engine shuts off for a minute or two, there is still lubrication for when the engine revs back up for acceleration.

For example, we use 5W30 oil (or 5W20) in our cars. This means that the oil flows with a low viscosity (lighter, thinner) of 5 at colder temperatures and a high viscosity (thicker, heavier) of 20 or 30 at hot temeratures. The hybrids might need to have a higher viscosity oil to keep it from getting so thin during operation that the oil drains into the pain while sitting at a stoplight - like maybe 15W60, or something like that, just guessing.

Chopsie

It'll be fine