What is that clicking noise that I always hear right after I turn off my car? No matter what type of vehicle it is, I always hear that clicking coming from under the hood for a minute or two after the engine is shut off. Am I overlooking something simple?
It is probably the various parts contracting as they cool down.
Probably heat shields.
What parts? All the clicking sounds pretty much the same, I would think once something’s settled, it’s settled. Anyone know what specifically I could be hearing?
In my truck, the most pronounced clicking I hear is coming from roughly where my catalytic converter is at. I’ve never actually gotten down there to check it out, but I always assumed that it was either the converter itself, or possibly the heat shield, cooling off.
As the metal parts get hot, they expand. Cooling off, the various sections may not cool at precisely the same rate, and there may be dissimilar metals in contact, as well. My guess is that the clicking noise is the parts (thin metal sheets, I believe) rubbing and skipping over one another as they change in size.
The catalytic converters get incredibly hot (does anybody have any temperature numbers?) - I believe it’s because the hot exhaust gases go through an exothermic catalytic reaction in the converter, which raises the temperature even more. I’ve always been warned about parking in tall grass - the converter can be hot enough to set the weeds on fire under your car.
It’s the cameras that the government has put in your car to record where you’ve gone. Now that I’ve told you, I’ll have to kill you.
In my Mazda 626 it was the telescoping antenna. The antenna was broken in the up position, and I bought the car used. I didn’t know it was supposed to have a telescoping antenna, and it took me a long time to figure it out.
I’m going with the cooling thing. Other possibilities: cooling fan slowing down, and stopping. Cylinders coming to a rest (probably not), uh… tiny… um… gnomes.
IIRC, exhaust gas is about 1500 F. Normally it cools to 150 or so by the end of the pipe, although the pipe itself is F’N hot! Oh, and I have set the grass on fire from a converter. Stuck 4x4, tall grass, revved engine, fire.
–Tim
I always thought that sound was oil dripping onto the oilpan.
My vote is the cooling of the engine making the noises. I hear the same thing in my house when the furnace turns on. It is the pipes expanding and contracting
Your car is pregnant and is letting you know. In a few days it will begin to seek out a secure nesting place. Give it a quiet corner in your garage, and let it have plenty of bubble wrap to use as nesting material. Give it lots of nuts and bolts to eat. Within a month you should have a new crop of volkswagens.
Do not try to take them away fro the mother until the are at least three months old, or she may snap at you. Clean up all il spills and give them plenty of transmission fluid.
Find good homes for them all, and be sure to have them mufflered. Don’t let them become strays. Our city streets and expressways are already crowded with abandoned cars.
WHen you turn it off, the fan keeps going until its cool…probably the fan check. Any car you say? Surely not.
The exhaust system is -wicked- hot. As it cools off, it changes shape and size (thermal expansion and all) the clicks you hear are the parts shifting around. You probably hear the same sound when you turn on your oven and then again as you turn it off.
Or maybe your car -is- pregnant.