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Discussion Starter · #1 ·
Volvo recommends, on page 59 of the 2009 Warranty Manual the following:

" Before switching off the engine, let it operate at idle for a short time to allow the spinning of the turbo-chargers compressor's turbine vanes to slow. After driving hard [whatever that means] this idle time should last a couple of minutes...."

I have not owned a turbo before; is this what most people do when driving the T6 or T5? Idle the engine before switching it off?
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

I do that. Or just drive it easy so you're not on boost much the last few minutes of your drive. Been doing it for 10 years, since my first turbo car, an Audi A4 1.8T.

People on the forums back then were so concerned many even got turbo timers, devices that would keep your car idling for a minute or two after you shut it off yourself to let things cool down (it was mainly to let the oil cool down a bit from what I used to read, and not get caked in the lines), and then automatically shut off the car and even activate the alarm.

Granted many of them had chipped their cars though, and were pushing 15 PSI of boost vs. the stock boost level of 7 PSI, so it was more important to be persistent about a proper cooldown if you wanted your turbo to last.

If you drive hard though, it's not difficult to work up the turbo. I used to see mine glowing red like this after a hard drive!

 

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Discussion Starter · #3 ·
Re: "Turbocharger Caution" - does anyone actually do this? (Lotus99)

How long do you idle before turning it off assuming a non-aggressive driving style?

This is all fascinating news to me...

This makes an even stronger case for replacing the oil at more frequent intervals and using full synthetic, unlike what Volvo uses at the factory.

Does it matter at all if you drive very short distances with the car?

Does the turbo have it's own idle timer? I remember back in the 80s a Volkswagen that would continue to idle after I turned it off. I don't remember if it was a turbo or not. Would this Volvo do the same, idle if it were overheated??
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Quote, originally posted by rovermark »
How long do you idle before turning it off assuming a non-aggressive driving style?
If you haven't been doing a run at 100 mph with the turbo on boost the entire time, driving a few miles at part throttle should be sufficient to let the turbo 'cool down'.

Quote »
This makes an even stronger case for replacing the oil at more frequent intervals and using full synthetic, unlike what Volvo uses at the factory.
Yes, it does. And do at least 2 oil analyses to zero in to what kind of change interval you should be following.

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Does it matter at all if you drive very short distances with the car?
It could. Which is one reason or doing a used oil analysis - to see if it actually has an impact.

Quote »
Does the turbo have it's own idle timer? I remember back in the 80s a Volkswagen that would continue to idle after I turned it off. I don't remember if it was a turbo or not. Would this Volvo do the same, idle if it were overheated??
There may be a pump that continues to push oil through the turbo after the engine is shut down; but I don't know for sure.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Quote, originally posted by rovermark »
Volvo recommends, on page 59 of the 2009 Warranty Manual the following:

" Before switching off the engine, let it operate at idle for a short time to allow the spinning of the turbo-chargers compressor's turbine vanes to slow. After driving hard [whatever that means] this idle time should last a couple of minutes...."

I have not owned a turbo before; is this what most people do when driving the T6 or T5? Idle the engine before switching it off?

Depends on how you have been driving. As a rule of thumb, my wife and I typically drive the car slower before we come to a stop IF we have been driving the car hard. For example, if we are on the highway and we have been driving at higher speeds and we pull off for gas or at a rest stop, we will coast or let the car roll on neutral before coming to a stop. Once stopped, we let the car idle for a minute or two and then shut off.

Going home, the two or three streets we have to go through before our driveway force us to drive a t very low speeds so no idle time is deemed necessary. Driving around town and then having to stop at, say, the grocery store, does not constitute (IMO) a requirement for idle time.

I have been using fully synthetic oil in my car since it had 3,750 miles so I also feel that under the mild conditions the oil provides an additional layer of protection.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

During the late 1980's I recall that turbo's first started appearing in turbo cars, may have been a Mazda (when they were still doing high product) I just cannot quiet remember. But I do know that after you turned off the engine the motor kept running for something like 3 minutes and this was directly due to the turbo.

I have done it for this vehicle and my forestor gt before. I dont know if it works but i do know i have never had any turbo probs.

cheers
 

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Re: "Turbocharger Caution" - does anyone actually do this? (GrecianVolvo)

I usually idle my car for about 30 seconds or a minute before switching it off whether it has been driven hard or not. But if it's been driven hard we usually ease off (ie. keep the engine out of the boost) 10 minutes before our destination.

Lotus, cool (I mean, hot!
) picture there... I've never seen a turbo glow red hot before.
 

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Volvo has been doing turbos for a long time now and they will last the life of the vehicle if taken care of. The cool down is a good idea if the engine has been worked. In day to day driving I don't bother. What you are trying to protect is the turbo bearings. By running hard and switching the engine off, the oil quits circulating. The oil left in the vicinity of the turbo gets "cooked". Full synthetics are more resistant to this heat breakdown.

Use a good synthtic and change at 8k kms (5k miles) and you won't have a problem.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (GrecianVolvo)

Quote, originally posted by GrecianVolvo »


Depends on how you have been driving. As a rule of thumb, my wife and I typically drive the car slower before we come to a stop IF we have been driving the car hard. For example, if we are on the highway and we have been driving at higher speeds and we pull off for gas or at a rest stop, we will coast or let the car roll on neutral before coming to a stop. Once stopped, we let the car idle for a minute or two and then shut off.


I actually think in that situation you describe you don't have to let it idle. My logic is to let the car idle so the turbo can cool down. The turbo would have worked if it was pushing boost. If you've not been on boost, which if you're just coasting at a constant speed more or less you wouldn't have been (unless you're driving up a hill I suppose...), then why bother?

Driving on the highway at constant speeds I think is as good as it gets in fact for letting things cool down b/c you're not on boost AND there's lots of good airflow to the engine.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (frontwheeldriven)

Quote, originally posted by frontwheeldriven »

Lotus, cool (I mean, hot!
) picture there... I've never seen a turbo glow red hot before.

While I should clarify that's not a picture of the turbo on my old Audi (I got it off the net), my turbo would glow like that easily after a spirited run. It was easy to see especially at night, I'd pull over, pop the hood, and could see it like it was lava flowing thru it! Made you grin!
 

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Re: "Turbocharger Caution" - does anyone actually do this? (GrecianVolvo)

I have been driving my Mercedes turbo-diesel since the mid 1990s and I treat it in line with Grecian. Around town, there is enough idling and speeds are low enough that the turbo is not spinning all that much. However, after maintaining highway speeds for a few hours, I always let it idle for a few minutes when I come to a stop. Typically, I let it run while I refuel it. This seems to alarm people at nearby pumps. Though I see a lot of Dodge Cummins drivers doing the same thing.

I believe the fear is that the turbo is so hot the oil in the bearing will evaporate, leaving the bearing dry on startup. Maybe this is less of a fear with synthetic oils.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (DaveWest1)

Quote, originally posted by DaveWest1 »
I have been driving my Mercedes turbo-diesel since the mid 1990s and I treat it in line with Grecian. Around town, there is enough idling and speeds are low enough that the turbo is not spinning all that much. However, after maintaining highway speeds for a few hours, I always let it idle for a few minutes when I come to a stop. Typically, I let it run while I refuel it. This seems to alarm people at nearby pumps. Though I see a lot of Dodge Cummins drivers doing the same thing.

I believe the fear is that the turbo is so hot the oil in the bearing will evaporate, leaving the bearing dry on startup. Maybe this is less of a fear with synthetic oils.

Your old diesel engine may be different that it may be in the boost to make enough HP at highway speed to push the car down the road. With the 2.5T or T6 I would suspect that the turbo is boosting very little at legal or even above legal speeds. The biggest danger to a trurbo would be a prolonged WOT (wide open throttle, full boost) situation(s) followed by an immediate shut down.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Comments above are all valid re: letting the turbo cool down before shut off. Gentle driving just prior to shut off and/or just letting it idle a bit prior to shut off are good practices. Comment about the factory fill oil is incorrect. It is in fact a semi-synthetic 5W-30 of very high quality. The owners manual suggests that use of synthetic is recommended for heavy duty driving but not required. This is driven mostly by cost of ownership concerns.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (ktm_525)

Quote, originally posted by ktm_525 »


Your old diesel engine may be different that it may be in the boost to make enough HP at highway speed to push the car down the road. With the 2.5T or T6 I would suspect that the turbo is boosting very little at legal or even above legal speeds. The biggest danger to a trurbo would be a prolonged WOT (wide open throttle, full boost) situation(s) followed by an immediate shut down.

I have no idea what you are taking about; it's a rocket ship.
 

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Discussion Starter · #15 ·
Re: "Turbocharger Caution" - does anyone actually do this? (DaveWest1)

Quote, originally posted by DaveWest1 »
I have been driving my Mercedes turbo-diesel since the mid 1990s and I treat it in line with Grecian. Around town, there is enough idling and speeds are low enough that the turbo is not spinning all that much.

How do you know if the turbo is spinning?
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Quote, originally posted by rovermark »


How do you know if the turbo is spinning?

Older turbo engines are not exactly subtle. With the Merecedes, when the turbo spools up, you hear a faint whistle and then the engine makes noticeably more power with no additional throttle. (A.K.A. turbo lag.) It is obvious accelerating from a stop in city traffic. At high speed, the turbo spools up almost instantly but the whistle is still audible.

For your T6, I assume Volvo did their homework and made the transition to boost imperceptible. Generally, though, the turbo is providing boost at higher RPMs when more power is summoned via the gas pedal.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Quote, originally posted by rovermark »


How do you know if the turbo is spinning?

1) Boost gauge

2)Put your computer readout to instantaneous L/km. Easy to tell when there is boost going on.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (rovermark)

Quote, originally posted by rovermark »


How do you know if the turbo is spinning?

When the engis is on (running) the turbocharger is always spinning. Its rate of turn (rpm) depends on how much boost is generated by how heavily you press on the gas pedal.

Low pressure turbochargers, generally, spin at lesser rpm (max can be in excess of 20,000 rpm) whereas high pressure turbochargers can turn as fast as 60,000 rpm or even higher.
 

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Re: "Turbocharger Caution" - does anyone actually do this? (Lotus99)

Quote, originally posted by Lotus99 »
While I should clarify that's not a picture of the turbo on my old Audi (I got it off the net), my turbo would glow like that easily after a spirited run. It was easy to see especially at night, I'd pull over, pop the hood, and could see it like it was lava flowing thru it! Made you grin!

Haha... still a cool pic! I haven't been surfing the Net enough... really don't have time!


Have you ever tried it on your T6? Even if you did I think it will be difficult to see the turbo from the engine bay because it's hidden behind...




Picture taken from topspeed.com... I have the same picture in my computer but I'm too lazy to upload it.


Quote, originally posted by cdauerer »
Comments above are all valid re: letting the turbo cool down before shut off. Gentle driving just prior to shut off and/or just letting it idle a bit prior to shut off are good practices. Comment about the factory fill oil is incorrect. It is in fact a semi-synthetic 5W-30 of very high quality. The owners manual suggests that use of synthetic is recommended for heavy duty driving but not required. This is driven mostly by cost of ownership concerns.

So, even if I thrash the living daylights out of the car with the factory fill, I shouldn't be doing any long term damage to the car right? I know I shoudn't attempt to reach that stage, but I did have some fun with my 2.5T when the car was 6 months old with 6k on the odo on factory fill. The local dealer does the first service at 15k/9months.
 
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