Dear Tom and Ray:
I am Kunaal from Mumbai, India, and I am a big fan of your show and column. I own a 2011 Skoda Fabia diesel hatchback that has covered 38,000 kilometers here, or 23,612 miles in your speak. Now, I know this car might not exist in America, but I quite love it. I am a car enthusiast and love my car and want it to last forever. It's a turbo diesel 3-cylinder engine that makes about 79 horsepower. Now, that's not a tarmac-tearing output, but in Mumbai, we have crazy, pothole- ridden roads and slow, bumper-to-bumper traffic most times, so the performance is good enough for use in the city. Every day when I start my car, I idle it for 30-60 seconds before driving off. And even after I start driving, I drive it slowly at first, without starting the AC for the first kilometer or two.
The idea behind this is to minimize any damage to the turbo-charger and engine during its warmup phase. At the end of the day, I repeat the same exercise in reverse: I switch off the AC a kilometer or so before stopping, and get all the cold air out of the vents with only the fan running. I then idle the car for about 30-60 seconds before shutting down for the day. My question: Am I being overly obsessive? Will these things help increase the life of the car, or am I just wasting precious time and fuel?
TOM: Are you being overly obsessive? Yes. Will any of these things increase the life of your car? Unlikely. But on the plus side, you're doing wonderful things for India's diesel-fuel industry, Kunaal! I'm sure it's grateful.
RAY: Modern cars really don't need to be warmed up unless the temperature is well below freezing. Then 30-60 seconds of idling is fine. But generally speaking, if the car starts and doesn't stall when you put it in gear, it's ready to go. And driving it gently is the best way to warm it up.
TOM: Plus, I think the average daytime temperature in Mumbai is around 90 degrees Fahrenheit year-round. So if you're starting your car, and the outside temperature is well below freezing, you've got bigger problems to worry about -- like how your roses are going to survive the oncoming ice age.
RAY: For cars with turbos, it's actually not a bad idea to let them idle for 30-60 seconds after driving the car hard. When there's a lot of demand on the turbo, it heats up. And allowing the oil to circulate through it for an extra minute or so allows it to cool down, which is beneficial.
TOM: But it sounds like you're hardly using the turbo, Kunaal. If you're in bumper-to-bumper traffic, that turbo probably is not kicking in at all. In which case, allowing it to cool off is completely unnecessary.
RAY: Turning off the air conditioner is hardly worth it, either. It does reduce the load on the engine a little bit, which means you use less fuel. But it makes very little to no difference in the life of the engine.
TOM: And besides, you have to think of the unintended consequences of what you're doing.
RAY: For instance, if you refuse to use the AC, you'll sweat more, which could send your dry-cleaning bills through the roof, putting a big dent in your beer budget, Kunaal. So be careful!
TOM: The best thing you can do to increase the life of your car is to simply drive it gently. Based on how much you obviously love the car, I'm guessing you already do that. And that's great.
RAY: That's what you should concentrate on, Kunaal. Avoid jackrabbit starts, sudden, hard acceleration and last-second braking when possible. Steer around a big, ugly pothole if you can do it safely. But otherwise, just enjoy the car -- and the air conditioning. Happy motoring.