Engine noise on acceleration and A/C high pitch noise - Corolla

Hi, I have a 2002 Corolla with about 180,000 miles that has been well maintained, but I know very little about cars.

Over the past months, I’ve noticed the engine noise on acceleration sounds a bit louder than I would expect it to, and it seems to be getting louder over time. It’s slow changing, so I’m a little unsure. And occasionally I wonder if I don’t hear a sound that shouldn’t be there, though I couldn’t describe it yet. Mechanic said the acceleration noise is normal at start-up for older cars until they get warm, but this happens even after I’ve been driving a while. Worth the $100 for an engine checkup?

Also, the A/C doesn’t seem to be the strongest and has a high pitch noise when I run it. Normal?

Yes, take it in for a checkup! Most shops do not charge for this if they are going to do the repair. And you will definitely need some repairs. If you keep driving you will have much more expensive repairs later.

Is the engine noise only heard when the AC is on? When you have your defrosters on the AC is on. My Corolla makes some grumbling sounds when the AC is on, I have had it checked and all is good. Is your oil level OK, has the oil and filter been changed less than 5,000 miles ago. The heat shield on the converter can make noise. It is worth taking the car in for a check they will look at this and a lot of other things too.