Q: I recently purchased a new PHEV, which provided instructions regarding the 1,000-mile break-in period. This has been my experience for many, if not all, cars purchased over the years. I intend to comply. However, I'm curious as to exactly what is happening to the engine during the break-in period. Also, is there any break-in required for the motor and battery?

R.R., Lisle, Illinois

A: There’s probably nothing in the owner’s manual about an engine break-in, yet I believe it is worthwhile. Having owned several motorcycles, I have learned the drill. Here are the steps:

1. Avoid constant engine speed for long periods. Vary the engine speed between 2,000 and 4,000 RPMs.

2. Avoid hard, jackrabbit starts. Accelerate gently.

3. Start the engine but don't let the engine idle longer than 3-4 minutes at a time.

4. Check the oil level. New engines may use a bit more than broken-in engines.

During break-in, the moving parts get friendly with the other stuff. Electric motors on the other hand, need no break-in.

Q: I have a 2023 Ford F-150 Ecoboost. I "accelerate" at times (why waste 400hp?). Friends have suggested that I change my oil every 500 miles instead of factory recommendations. They say that my driving habits cause it to run a little hot. I love the performance, but do want to protect the engine.

S.G., Antioch, Illinois

A: Do your friends work for an oil company? Your engine will run at the same temperature (about 200 degrees Fahrenheit) whether you are cruising or mashing on the gas. Your oil company friends should be pleased with your frivolous use of fuel.

Q: I'm the original owner of a 2011 Kia Sorento EX with a 3.5-liter V-6 engine and 133,000 miles on the odometer. I have maintained the car to the best of my ability and have for years changed the oil myself every 2,500 to 3,500 miles, and still do, even at the age of 94. In the past six months or so, I have noticed a slight metallic "chi, chi, chi" staccato rattle sound coming from the engine, which I suspect to be the timing chain or valve lifters. I'm concerned the chain will break and cause complete failure of the engine. There have been no dash warning signals of any kind. In one of your columns, you said the chain should last the life of the car, but I'm not sure what that might be. Your expert opinion please.

J.G., Huntley, Illinois

A: There are two possibilities. Chances are you don’t need a timing chain although the chain is a component in the camshaft operation. The variable cam timing system actuators may be the first problem. The second culprit may be the fuel pump. Unlike most vehicles today that have electric fuel pumps in the gas tank, Kia has a mechanical pump driven by the camshaft that is easily replaced.

Q: Took my 2024 Toyota Corolla Cross Hybrid in for first service at 5,000 miles (as reminded repeatedly and irritatingly via text). Expected an oil change. Instead, I was told "only a tire rotation now." Oil changes will happen every 10,000 miles but tire rotations are required every 5,000 per dealer and "Toyota recommendations." Overkill?

T.S., McHenry, Illinois

A: Your question harkens back to one I got a couple weeks ago. Tires, fresh from the factory, do not last as long as replacement tires. Additionally, the weight of hybrids and electrics is hard on the tires. Your dealer may be trying to make them last as long as possible. You may choose to ignore the overkill, but tire demise may occur prematurely.

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