evilgabbie

got a 2.0T.. first turbo car.. after hard driving, the exhaust manifold thing is glowing hot

is it ok to turn off the car and just let it cool or should i do something about it ?

i noticed if i shut off the car, the engine/fan keeps running for a while until it's cool down...

what do you guys think ?

gunde

After driving your car hard, it is a good habit (read the manual) to let the car idle for a minute. That cools the turbo a bit. When you shut down the engine, no oil and no coolant run through it. With a hot turbo, the small amount of oil left in it just cooks and the bearing (the sleeve in a k03) is left without lubrification : not good ... Just take the habit of coasting for awhile before arriving at your destination or wait a minute before shutting down the engine.

evilgabbie

yeah i read the manual, it doesn't say anything about it.. or maybe just too many pages to read.... sigh

coast a bit or just idle is alrite =)

thx

Corrado_Guy

The general rule with a turbo car is to drive it really nicely the last few miles of your trip and let the car idle for a minute or two to allow the turbo to spool down. Many people use turbo-timers to let the car idle for a bit after you have left the car. As stated above the turbo spins at very high speeds and literally cook any oil in the bearings causing wear or damage. The Audi's in the old days (pre-1985) used to have only oil feed turbo's and these cars had a habit of eating turbos after a while. Once Audi started to cool the turbo's with coolant as well the number of worn turbo chargers declined drastically. So if you drive the car really hard just before you are finished with your trip then let the motor idle for a couple of minutes and if it was a short trip the 10 - 20 seconds is enough. You are trying to reduce the turbine speed and take some of the heat away from the motor. Leaving the motor idling allows you to feed the turbo bearings with oil while it spools down.

You must excuse my ignorance as I don't actually own one of these cars yet but does the 1.8T motor not use an secondary coolant pump for the turbo? Most newer turbo cars use a secondary coolant pump that circulates coolant through the turbo when the motor is running and for 10 minutes or so after the car is turned off. If it doesn't it should, this pulls heat away from the turbo after the motor is turned off which greatly reduces coking.

evilgabbie

"
You must excuse my ignorance as I don't actually own one of these cars yet but does the 1.8T motor not use an secondary coolant pump for the turbo? Most newer turbo cars use a secondary coolant pump that circulates coolant through the turbo when the motor is running and for 10 minutes or so after the car is turned off. If it doesn't it should, this pulls heat away from the turbo after the motor is turned off which greatly reduces coking.

"

actually when I turn off the car after some semi-hard driving, it seems like everything is still running under the hood, not just the fans... I don't see the belt and pulleys moving but everything else seems like it is.. maybe it might be ok to just turn off the car afterall, and maybe audi has an automatic system now ?

Corrado_Guy

It is still a good idea to let the turbo spool down and let the car idle for a minute or two when you have been driving the car hard. The cooling system can pull some of the heat away from the turbo which is good but when you shut the motor off you stop the lubrication which is bad. The turbo impeller carries a lot of inertia so when the motor is shut off this thing will continue to spin until it runs out of momentum. If the turbo is really hot and you shut the motor off then the heat & motion in the bearings will literally bake the oil left in the bearings which then expand with increased heat and wear or damage occur.

Cooling the turbo with coolant didn't really get rid of the problem with wear, it just extended the service life of the turbo meaning it usually broke when the warranty was over. Using high quality synthetic oil, frequent oil changes, and letting the car idle for 30 - 120 seconds can greatly increase the life of the turbo. If you don't want to wait a turbo timer may work for you.

evilgabbie

is there a specific turbo timer i should be shopping for ?

Q-ball

I guess that explains the nose I hear when turning off the car....