2015 Toyota Corolla Automatic
110,000 Mileage
Hello,
Taking a shot in the dark, here. I took my 2015 Corolla to two shops, that haven't been able to diagnose a problem and am seeking advice. During cooler weather days (about 60F or below), after starting (and about 15 mins after), the car makes a rapid grinding/vibration/scraping sound, that seems to be coming from the exhaust area directly under the mid point of the car. This only occurs when the car is in Park or Drive, and reverse works fine. After the car warms up a few miles down the road, the sound goes away for the most part. The shops could not reproduce the sound, because the car was warm by the time I got it to them, and there was no sound being made. I would also note that the sound gets louder and faster as I accelerate. I've used my limited knowledge to try to rule out a dew things by looking both under the hood and car, and nothing seems immediately obvious, except the exhaust pipe under the driver seating area is a little loose. In the meantime, I've kept it parked until I get this issue resolved. Thanks for any input.
There are times a person needs to leave the car at the shop overnight, so the mechanic can do a real cold start to diagnose the problem. This sounds like one of them, especially as you aren't driving the car anyway.
Could just be a leaky gasket between connections in the exhaust pipe that seals itself somewhat after warming up.
Those aluminum heat shield can rattle until the heat expands them. Flex connections are also notorious for noise.
Maybe call a muffler shop and ask if they can test the exhaust for leaks.
