I've often been told that driving through puddles (anything from a small one to 3-4cm deep) can be bad for my car, and I shouldn't drive through them.
I know about aquaplaning, but is there any other damage driving through puddles can do?
I mean in general, so I could also be doing at high speeds, so there is quite a big splash...
EDIT: Does it have any effect on the brakes as well?
Your car may have plastic guards underneath to stop water from spraying up on sensitive components, but everything under the hood is typically waterproof to some degree. That said, the only "damage" I have ever seen is the spray of water loosening or tearing off plastic guards that are not properly fastened or half-way ripped off already.
The basic short answer is, it shouldn't break anything that isn't somewhat broken already. Cracked light housings could get wet, etc.
If the water is deep enough that there is a huge rush of water over the front of the car or the engine bay, you could suck some water into the intake, but then again, the intake/air filter housing is made to deal with this as well.
Added: The heat from the brake system should dry them very quickly. There will be a momentary loss of a little braking power, but shouldn't be very noticeable. Most of the splash will be directed away from the wheels, so the brakes might not even get wet.
I personally love to hit puddles at high speed to see the big spray. My wife hates it.
Edit based on comments...
For safety, don't speed on residential streets and never hit a big puddle unless you've driven over the same spot in dry weather. Chances for hydroplaning are great, so go over puddles in a straight line and avoid steering or braking input until the puddle is crossed.
Large waves of water can "hydrolock" the car if water is sucked into the engine, which is bad. The intake is made for splashes, not waterfalls.
I had a buddy years ago who liked to do the same thing. Our big plans were cut short one evening when he hit a good sized puddle and managed to knock his muffler completely off. It was surely loose before, but it would have been nice to repair it some other time.
It certainly won't help anything.
If you splash pedestrians, you won't win any friends, particularly if they know who you are or where you park.
If spotted by the police, there's a good chance you'd get pulled over for erratic driving if only to get a lecture.
Another consideration is that you're only expecting a shallow puddle. Depending on where you live, what appear to be springtime puddles often conceal cavernous potholes which won't do your tires, rims or suspension a bit of good.
Wet brake pads don't stop as well\quickly as dry ones. I remember this as more of a issue with drums vs discs, but I still always hit the brakes lightly after a puddle to help them dry.
Also if you have any tire problems already (say a weak spot on the side wall), the shock from the bump may be enough to make the weak spot into a blow out.
But hey....big splashes are fun.
If you have just been doing some heavy braking, making the discs very hot. Cooling them very quickly by driving through water could warp the discs.
One downside is that you can't seen how deep a puddle is, or if there is a big hole in it. You could cause some suspension damage by hitting a big pothole hidden under (inside?) a puddle.
Drove my truck (Dodge Dakota) through a large puddle on my street last week, about 18" - 24" deep. Then I stopped to fill up on gas the day after. Surprise! the tank would not take gas. After two days at the garage, they found out that a gas tank vent hose and the charcoal filter were full of water. $500.00 Don't do it!!!!! (drive through puddles)
I hit this puddle at 60+ MPH. I have the intake above the roof now, as well as some plastic sleds screwed underneath, but I didn't at first.
Initally the distributor got wet which caused some misfiring until I took it off and dried it out; now I've coated it with silicone.
No permanent damage has resulted; though I know what this looks like when it's dry so I can verify there aren't any rocks or potholes in it. Those are more likely to do damage to your car than the water will.
Puddles may hide potholes
This is my main concern when I drive over a puddle. You will never know before you hit a puddle if it has a huge hole. I bent a rim like that doing 50Km/h
You may hydroplane
In this case you can predict by the speed you are doing. Mind that the deeper is the puddle the lower the hydroplaning speed.
Other than that, there is little damage that you may expect to ever happen to you car.
