ASK THE AUTO DOCTOR
Q: I have a 2018 Chevy Silverado. What modifications can I make to the engine and chassis without running into problems with voiding warranties? I don’t want to do something and have General Motors say it was my fault for changing or adding something. — Joel.
A:
I’ve done a lot of bolt-on items. The one area of most concern is changing the exhaust to dual tailpipes. Usually the replacement muffler is smaller and much louder than the stock system with no advantage except noise. Other options include a fresh-air intake (coldair intake) system and a computer download re-tune. For best performance, it may require premium gasoline. Be advised I would download the stock (original) tune to the ECM (computer) before going in for service. Your Silverado is a great truck with lots of power and comfort.
Q: The Toyota Yaris has been around for while and I’m considering downsizing to a small car, so since it’s been around for a while, I’m wondering if you have any opinions on it. — Alan.
A:
The Toyota Yaris was not one of my favorite cars a few years ago, but I find the 2018 Yaris to be a solid Toyota product. The Yaris has grown up and now I consider it a good compact car. It comes with either a manual transmission or four-speed automatic. I drove the automatic version. The fuel economy fell short of my expectations of 32-33 mpg. I think gas mileage would be better if equipped with a 5-speed automatic. The Yaris is easy to drive and park, with good visibility from all windows. There are many options when it comes to vehicle selection, so take your time on a road test and mark all the pros and cons.
Q: I bought my 2012 Toyota Corolla used with 20,000 miles on it; it now has 88,000 miles. When I start it in the morning, the engine squeals very loudly and then the noise eventually stops. Even during the day after it sits a couple of hours it will still squeal for a while. This has been happening for the last six months. I tried turning the ignition key slower than I normally do thinking the computer needs more time to start things moving but it still happens. — Marcia.
A:
A squealing sound when started is usually caused from a loose or worn alternator belt. In some rare cases, the power steering or air conditioner belt could also be the fault. Most late-model vehicles have an automatic belt tensioner that ensures the correct tension. The sound has nothing to do with the key turning or computer. Do not use a cheap off-brand belt for replacement.
Junior Damato is an ASE-certified Master Technician. E-mail questions for publication to info@motormatters.biz