My 2008 (189,000ish miles) is making a noise that reminds me of two ceramic coffee mugs clinking together. It's quiet in the car, but pretty loud when you are outside the car. I've had two mechanics and my husband, who knows his stuff, look at it and don't have a solid answer. The mechanics used a stethoscope and decided it was coming from back by the muffler somewhere, but from in the car it sounds like it's coming from the engine.

The noise happens when the car is working harder - climbing hills (AC on or off), going over 75 mph (AC on or off), or any time the AC is on, even if I am idling.

Pre-ignition was suggested, but we've used Berryman's B12 in the tank and premium gas and it's not helping. I really need this car to last a few more years.

Has anyone had this experience? I'm afraid to take it to the dealer. I'm afraid I will spend thousands trying to diagnose it. The car isn't worth that much, but I can't afford a new one right now.

 

Could be the Cat. It has a ceramic honeycomb coated in rare metals to help make the exhaust be cleaner. It's located on the underside of the car just about where the driver and front passenger would sit.

Another bit of testing to see if it's got to do with the rear suspension is to have the car jacked up and on quality jack stands. Start by grabbing a rear tire and pull on it. It shouldn't make any noise. Wiggle it from left to right and top to bottom. It shouldn't make any clunking noise at all. Then take a small pry bar and pry against all ball joints and rod ends to see if there is any movement. There is not be be any. You are hoping to find a movement so that you know what to replace.

These are just guesses for something to look at. Use YouTube to get a better idea of testing wheel bearings and ball joints as my description will be found lacking.

 

Loose spark plug!