Parking brake: In Minnesota, use it or lose it

Also, another friend is a stickler for turning off every single accessory (fan, radio, etc.) before turning off the ignition. The claim is that it saves battery life, as the battery doesn't have to work so hard to start the car. In theory this makes sense to me, but are today's batteries really harmed by leaving the radio on?

A Fun questions. Thanks for asking. The key to parking brake use in Minnesota is to make a fundamental decision -- either use it each and every time you park the vehicle ... or don't use it at all. The issue isn't so much the transmission, it's the potential for rust and corrosion on the parking brake cables underneath the vehicle. With the salt and sand spread on our roadways each winter, these cables can easily corrode to the point where the parking brake mechanism can rust solid and stick. If it sticks with the parking brake applied, well, you're going to sense that something's holding back the performance of your vehicle, and very shortly you're going to smell a very acrid odor from overheated brakes.

The key to preventing the buildup of rust on the parking brake cables is to use the parking brake every time you park the car. This "exercise" will perform a "self-cleaning" process to help keep the cables rust-free and functional. Intermittent or irregular use of the parking brake is the worst scenario. Enough rust can build up to stick the parking brake in the "on" position the next time you apply it overnight.

So, as I mentioned at the top, either use the parking brake every time you leave your vehicle, or don't use it at all -- ever.

In regard to the transmission, when you place the shift lever in "park," the linkage engages a steel "pawl," or finger, into a detent to mechanically lock the transmission and keep the vehicle from moving. If you're parked on a significant hill or grade, the weight of the vehicle ends up "leaning" on this pawl engagement, often making it difficult to pull the shift lever out of the park position when you're ready to drive away.

Having the leverage of the vehicle's weight "leaning" on the pawl isn't particularly hard on the transmission, but your efforts to pull or force the shift lever out of park can potentially bend or damage these components.

That's why most folks, particularly those who live in hilly terrain or on a grade, should get into the habit of engaging the parking brake every time the vehicle is parked.

Setting the parking brake -- regardless of terrain -- before shifting into park reduces the load on the parking pawl as well.

About your question about turning off all the vehicle's accessories before starting the engine -- it's really not necessary. Next time you're ready to start your vehicle, turn the heater fan on to the high position, then engage the starter. Notice how the fan stops as you turn the key to the start position? Most modern vehicles bypass accessory operation in the start position, including their DRLs -- daytime running lights -- then re-energize the accessories that are turned on as the key is released to the run position.

Even if the ignition didn't do this, there's no significant harm to the battery by leaving the accessories in the on position. The majority of accessories, including the radio, draw very little amperage from the battery. Even those that do -- headlights, fan and rear window defroster -- only draw a fraction of the amperage that the starter motor does as it cranks your engine. And most of these accessories, except perhaps for the fan and radio, will likely be in the off position at start-up anyway -- so not to worry.

Q I recently purchased a Ford F-250 pickup with 27,000 miles on it. When I shut the engine off, even on a dry day after a short drive, the muffler clicks and pops for a minute or so. It sounds a bit like water dripping on the muffler, but I have eliminated that option.

My friend said something about combustible gases. I doubt that it is an issue, but I would love some peace of mind concerning my gigantic investment.

A You're right, it's nothing to worry about. I've noticed this phenomenon on new or newer vehicles, and it's nothing more than the rapid contraction of the various metals in the exhaust system as it cools rapidly after shutting off the engine. The interior chamber of the catalytic converter can reach temperatures of more than 600 degrees Fahrenheit, and the interior of the muffler has a series of chambers and baffles that expand and contract as the system heats up and cools down.

Unless you hear the distinctive "pop" of unburned fuel igniting in the exhaust system after shutdown, the noises you hear are perfectly normal and of no concern.