Cold engines make a lot of noise these days.

I get a lot of questions as to why a brand new vehicle with only a few hundred miles on it is so noisy when it is cold. Lots of rattles and clanking in the engine compartment. Here's why.

Most automotive manufacturers are building their engines at the high end of clearances of the internal parts. This has a big advantage to the manufacturers - they can pass the EPA requirements for fuel economy. You see if the clearances are loose then the frictional losses of the engine are minimized. Lower friction = greater fuel economy.

The downside of this practice is that the engines are very noisy when they are cold. As they warm up they quiet down considerably since the internal parts expand and the clearances are diminished. I have heard of this complaint from many of my readers. There is not much you can do about it except complain to the dealership. The problem is that the complaints fall on deaf ears. Unless you can show that there is a performance problem they won't fix it!!

Look on the positive side. Every time you hear your cold engine rattling like a bag of bones remember that you are getting perhaps 1 mile per gallon better fuel economy!!

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