My buddy who is attending school to be a mechanic recently told me on turbocharged vehicles (like my GTI) the engine is supposed to sit at idle least a minute after driving to allow the turbocharger to cool the oil that is spinning the bearing/shaft. If the turbo is not allowed to cool itself down, then the oil will be "cooked" and can lead to problems. Can I get any confirmation on this information? Is it a myth?
Turbocharger Cooking Oil? Myth?
- Thread starter lancerplayer
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true to a certain extent. if you use quality oil you wont really have a problem with oil coking onto the shaft of the turbo.
but with the amount of heat that is generated at the turbo letting it idle for a minute is hardly enough time to realistically cool it down enough to a "safe" temperature...it would take about 5-10min for the oil temp to come down far enough...but no one has that much time to wait.
just use a good quality synthetic oil and you wont have a problem.
but with the amount of heat that is generated at the turbo letting it idle for a minute is hardly enough time to realistically cool it down enough to a "safe" temperature...it would take about 5-10min for the oil temp to come down far enough...but no one has that much time to wait.
just use a good quality synthetic oil and you wont have a problem.
This is not a myth do some google searching. Many diesel engines equipped with turbos have shutdown timers to prevent this very thing. I'm not sure the explanation he gave you is 100% correct, however a turbocharged engine does need to cool down before shutting down the engine, and more than one minute after say a hard run 3 minutes at least. If normal easy driving I doubt you need any idle cool down time.... this is from my own research, and opinions formed from owning diesels etc,.... they may not be 100% correct.
If your turbo is oil cooled only and you've just done long trip or a lot of hard driving then yeah, you should let it idle for a bit before shutting it off. This is where turbo timers come in handy.
For an oil and water cooled turbo it isn't as big of a deal. I still wouldn't do a hard WOT highway pull and shut it down quickly thereafter. I think Subaru advises to idle the engine for 30 seconds or something before shutting it down after a long highway trip or hard driving.
For an oil and water cooled turbo it isn't as big of a deal. I still wouldn't do a hard WOT highway pull and shut it down quickly thereafter. I think Subaru advises to idle the engine for 30 seconds or something before shutting it down after a long highway trip or hard driving.
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What they don't want you doing, even if you're normally aspirated, is to come off the highway from a sustained high output state and immediately shut down. You need to allow the reserve capacity of the cooling system (which is probably tied to your oil temp via an exchanger) to normalize. At high output you're probably at some "JIT" (just in time) throughput rate.
If you're tooling around the development after your highway commute there should be no need for a prolonged cool down. After you've dumped excess from the turbo, the oil isn't going to get much cooler the longer you idle.
If you're tooling around the development after your highway commute there should be no need for a prolonged cool down. After you've dumped excess from the turbo, the oil isn't going to get much cooler the longer you idle.
Turbo cars need to have electrical pumps that keep oil flowing for a minimum of 5 minutes after a sustained period of high turbo temperatures, IMO.
That could even be used in conjunction with a bypass filter.
As said here already no real need to idle down long under in most conditions in a modern turbo app with water cooling and Id imagine even water to to oil cooling so long as you drive it down like coming into your development. However, you do want to allow the turbo time to stop spooling so you dont shut off a part that will still move without oil circulating over it. I personally allow about 15 seconds of so for this.
Originally Posted By: lui
true to a certain extent. if you use quality oil you wont really have a problem with oil coking onto the shaft of the turbo.
but with the amount of heat that is generated at the turbo letting it idle for a minute is hardly enough time to realistically cool it down enough to a "safe" temperature...it would take about 5-10min for the oil temp to come down far enough...but no one has that much time to wait.
just use a good quality synthetic oil and you wont have a problem.
Would Shell Rotella T6 5w40 fit the bill?
true to a certain extent. if you use quality oil you wont really have a problem with oil coking onto the shaft of the turbo.
but with the amount of heat that is generated at the turbo letting it idle for a minute is hardly enough time to realistically cool it down enough to a "safe" temperature...it would take about 5-10min for the oil temp to come down far enough...but no one has that much time to wait.
just use a good quality synthetic oil and you wont have a problem.
Would Shell Rotella T6 5w40 fit the bill?
Some aftermarket remote starters have a setting for turbo where you can pull a key out of the ignition, lock the doors and the remote starter will shut off the engine after 3 minutes.
There's a good Mobil 1 video on youtube that shows the coking deposits on a turbo.
Early saabs used to recommend idling for 30 seconds before shutting down to prevent oil starvation and for cooling. Those turbos ran around 90,000 rpms as I recall and if you shut it off immediately like Gary was talking about say from the highway or hard driving, the oil supply is shut off while it is still spinning at a very high rpm. Probably not as much of an issue with more modern turbos however.
The newer VAG cars continue to circulate coolant after the car is shut off for quite a while. I know the vw 2.0 FSI does but I don't know about the 1.8T.
Early saabs used to recommend idling for 30 seconds before shutting down to prevent oil starvation and for cooling. Those turbos ran around 90,000 rpms as I recall and if you shut it off immediately like Gary was talking about say from the highway or hard driving, the oil supply is shut off while it is still spinning at a very high rpm. Probably not as much of an issue with more modern turbos however.
The newer VAG cars continue to circulate coolant after the car is shut off for quite a while. I know the vw 2.0 FSI does but I don't know about the 1.8T.
Ive seen some gnarley coked up turbos off of 6.0's. Our diesel tech showed me one that was so pull of carbon the vanes wouldn't move even if he pushed on them. btw the turbos on 6.0's are variable geometry.
Originally Posted By: lancerplayer
Would Shell Rotella T6 5w40 fit the bill?
that's what im using now. and i was using Royal Purple before that. hard to say how the turbo is holding up without taking it apart but it's been on the car for 4-5 years and it's still kicking. recently pumped 440+hp on the dyno.
i have an oil temp gauge installed....believe me....it take at least 10min of idling for the temp to drop from over 210F to under 190F which is still very hot...and trust me the shaft of the turbo is gonna be much hotter than that.
the 1min of idle time makes no sense to me...if anything the radiant heat from stopping air flow from moving actually make it hotter under the hood and in the engine.
use a good oil and you wont have an issue..
Rotella T6, Royal Purple, Amsoil, Redline, Mobil 1 will all work really well.
Would Shell Rotella T6 5w40 fit the bill?
that's what im using now. and i was using Royal Purple before that. hard to say how the turbo is holding up without taking it apart but it's been on the car for 4-5 years and it's still kicking. recently pumped 440+hp on the dyno.
i have an oil temp gauge installed....believe me....it take at least 10min of idling for the temp to drop from over 210F to under 190F which is still very hot...and trust me the shaft of the turbo is gonna be much hotter than that.
the 1min of idle time makes no sense to me...if anything the radiant heat from stopping air flow from moving actually make it hotter under the hood and in the engine.
use a good oil and you wont have an issue..
Rotella T6, Royal Purple, Amsoil, Redline, Mobil 1 will all work really well.
Originally Posted By: lui
Originally Posted By: lancerplayer
Would Shell Rotella T6 5w40 fit the bill?
that's what im using now. and i was using Royal Purple before that. hard to say how the turbo is holding up without taking it apart but it's been on the car for 4-5 years and it's still kicking. recently pumped 440+hp on the dyno.
i have an oil temp gauge installed....believe me....it take at least 10min of idling for the temp to drop from over 210F to under 190F which is still very hot...and trust me the shaft of the turbo is gonna be much hotter than that.
the 1min of idle time makes no sense to me...if anything the radiant heat from stopping air flow from moving actually make it hotter under the hood and in the engine.
use a good oil and you wont have an issue..
Rotella T6, Royal Purple, Amsoil, Redline, Mobil 1 will all work really well.
We're not talking bulk oil temps, we're talking about the shaft. EGTs are what you want to watch. The shaft heats up quickly, and cools quickly. You want the oil to carry this heat away.
Stopping airflow? Exhaust is always moving through the turbo. We're talking about the shaft, not the engine and not the housing. At idle this air (exhaust) is much cooler than when the engine is under load.
Originally Posted By: lancerplayer
Would Shell Rotella T6 5w40 fit the bill?
that's what im using now. and i was using Royal Purple before that. hard to say how the turbo is holding up without taking it apart but it's been on the car for 4-5 years and it's still kicking. recently pumped 440+hp on the dyno.
i have an oil temp gauge installed....believe me....it take at least 10min of idling for the temp to drop from over 210F to under 190F which is still very hot...and trust me the shaft of the turbo is gonna be much hotter than that.
the 1min of idle time makes no sense to me...if anything the radiant heat from stopping air flow from moving actually make it hotter under the hood and in the engine.
use a good oil and you wont have an issue..
Rotella T6, Royal Purple, Amsoil, Redline, Mobil 1 will all work really well.
We're not talking bulk oil temps, we're talking about the shaft. EGTs are what you want to watch. The shaft heats up quickly, and cools quickly. You want the oil to carry this heat away.
Stopping airflow? Exhaust is always moving through the turbo. We're talking about the shaft, not the engine and not the housing. At idle this air (exhaust) is much cooler than when the engine is under load.
I just make sure I go easy on the car for 10 minutes or a few miles before I shut it off. If I pull off the race track, I turn the defrost on full heat/high fan, and let the car idle for 10 minutes. My car has an oil/coolant heat exchanger and the turbo is also coolant cooled.
Just drive easy for a couple miles before you park it.
Just drive easy for a couple miles before you park it.
Are we talking about a Chrysler "K" car with a turbo or a Porsche' Carrera Turbo or a BMW or an Acura?
It's all about engineering.
Acura/BMW/Porsche' for some reason seem to do better than others.
There are issues with the Eco Boost system on Ford products causing seizures. I can only imagine why.
It's all about engineering.
Acura/BMW/Porsche' for some reason seem to do better than others.
There are issues with the Eco Boost system on Ford products causing seizures. I can only imagine why.
no myth but idling isn't necessarily the best either. Idling is the lowest pressure you have, the best way to cool the housing, shaft, egt's, and bearings is to come down from your high boost blast with a some high idle light load (1500-2300rpm), that keeps the oil pressure high and some light effort flow through the housing.
also, look up "turbo timers" that keep your engine running for a set time after you pull the key and walk away..
-rick
also, look up "turbo timers" that keep your engine running for a set time after you pull the key and walk away..
-rick
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You can do it with pre-post oilers too. I don't know of too many gassers that monitor EGT's ..that's mainly a diesel thing.
Mazda still recommends at least 15 secs of idle before shut down if turbo been in action. I would keep my car to idle a bit after extended highway use anyway regardless of tubo or not. Rest area is a place to watch what your doing with your car.
Originally Posted By: hooligan24
I just make sure I go easy on the car for 10 minutes or a few miles before I shut it off.
Just drive easy for a couple miles before you park it.
Best answer.
If you drive it gently for the last 10 minutes after a hard drive its usually enough to prevent any possible problem.
I actually think that the mid 80s SAAB 900 Turbo owners manuals actually worded their instructions just this way.
Speaking of which I remember those well.. great cars . I hope SAAB makes a huge comeback with their new owners!
I just make sure I go easy on the car for 10 minutes or a few miles before I shut it off.
Just drive easy for a couple miles before you park it.
Best answer.
If you drive it gently for the last 10 minutes after a hard drive its usually enough to prevent any possible problem.
I actually think that the mid 80s SAAB 900 Turbo owners manuals actually worded their instructions just this way.
Speaking of which I remember those well.. great cars . I hope SAAB makes a huge comeback with their new owners!
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