Hi all,

So my 2009 S60 2.5T manual says that you should idle momentarily before shutting the engine off to allow the turbo to cool down. I have some questions about this.

1. What if the last 30 seconds to 1 minute of my drive involves moving slowly through the parking lot where I work, do I still need to idle for a while when I reach my parking spot?
2. What if I'm not using the turbo that much, i.e. not accelerating fast, as I go to and from work, is it still necessary to idle for a while after parking?

Thanks

 

I believe it's just after lengthy drives, or when you drive the car really hard. I'll let it cool for 30 seconds or so before shutting it off if I drive it really hard, but I think in most cases, slow speeds and gentle acceleration that don't require much boost counts as "chilling" the turbo, which is like pulling into a parking lot, looking for a parking space, etc.

 

Idle for another 30 seconds to a minute. It certainly wont hurt it, and I would guess you can spare it.

What I do - is pull into my spot, get my cell phones together, wait until the song I am listening to ends, and shut her down.

 

The turbo itself spins very fast and is cooled by oil. What you're trying to accomplish is to cool the turbo with flowing oil. Shut off the engine, you shut off the flow of oil. If the turbo isn't cool, the oil will cook. This was a major 1980's problem when Chrysler had lots of turbo engines. Crud developed in the oil passages from cooked oil, reducing the flow of oil and shortening the turbo's life.

Given the absence of boost gauges in Volvos, you aren't 100% sure that the turbo hasn't been under pressure and heating up. For the 30 seconds it takes to let it idle, its a small price to pay for assurance that it is cooling down.

This is also why many use synthetic oil in turbo models -- that oil is more heat resistant than conventional oil.

If you cruise the parking lot at idle, you're safe. But the gas pedal is the enemy.

 

This is the way I look at it.

 

Synthetic oil pretty much negates the need for a turbo timer. If the RDX comes stock with synthetic, theres nothing to worry about.

Conventional oil was the reason turbo timers became popular, since it had a tendency to scorch and "coke" up the inside of the oil feed/return lines, eventually grenading the turbo due to lake of lubrication. Synthetic oil is highly resistant to doing this, which one of the many reasons it is superior to regular oil.

If you're that worried about it, just let the engine idle down a minute or two if you have driven it especially hard. not a bad idea for any car.

as far as turbocharged engines dieing faster than N/A motors, again thats rubbish now that sythetic lubricants are commonly used.
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