I'm right at 5000 miles and ever since I have had the car upon startup I hear a clunk from the driverside under the hood. This has only happened 5 times, I will start the car 2 seconds will pass and I will feel and hear a loud clunk. Since it rarely happens I know the dealership will not be able to duplicate the problem. Yesterday it happened so loud that i shut thecar off and checked under the hood. I was just wondering if I'm alone with this happening or if other have experienced this as well. This is totally different from the suspension clunk due to the fact that the car is still parked when this happens.

 

Does it happen when putting the car in gear or just sitting there at idle?

 

This is your A/C unit. It happens on alot of Ford vehicles. Basically, the vehicle has been shut off with the A/C on. This will be either in the defrost mode, or in the cooling A/C mode. The system retains pressure and after start up, the A/C is basically "burping" the excess out. Been happening for years on Ford vehicles. When you turn your vehicle off, leave it in the vent position, so the interior of the vehicle can breath, and it will let your A/C system "depressurize", for lack of a better term.