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I have a 2002 1.8 turbo and everyday during rush hour I drive 30 miles in the morning (15 miles each way with about an hour and a half between each way) I usually get up to 80 mph and then the car sits for 4 hours. Sometimes after it sits it's hard to start up again, but once it's on it runs normally. Could this be because I don't let the turbo have time to cooldown?
 

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Sometimes after it sits, it's hard to start up again. But once it starts, it runs normally. Could this be because I don't allow the turbo time to cool down?
Probably nothing to do with cooling your turbo. There is a chance your Coolant Temperature Sensor, your MAFS, your spark plugs, your throttle body or a vacuum leak is part of your problem. Get it scanned for codes and post the entire list of code numbers in this thread.

With regard to turbo cooling... When the engine is running, oil is being pumped through the turbo. The turbo gets extremely hot. If you're running a chipped engine and/or "in boost" alot, the turbo can even get hot enough to glow. When you shut the engine off, the oil in the turbo stops flowing. Any oil sitting stagnant in the HOT HOT HOT turbo can over-temp and break down. This cooked oil can form globs of thick sludge and/or chunks of hard coke. This is why it's so important to use the proper spec oil in these engines. You need to use an oil that can survive in this environment.

If you feel you are pushing your turbo hard and getting it hot enough to require a cool-down, take the last mile of your journey easy and try to stay out of boost. Upon arrival, let the car idle a minute before shutting the engine off. This should allow the turbo enough opportunity to go from super hot to just plain normal hot. Give this a try and see how your car responds. My guess is, allowing for a turbo cool-down won't effect your hard-start problem.
 
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