Things We Do To Our Cars: What’s Worse?
By Eric Peters, Automotive Columnist
What’s worse?
Under or over-inflating tires?
A couple extra psi of air pressure in your tires will result in a harsher ride as well as faster tread wear. Tires inflated significantly above the maximum recommended pressure may also pop just like a balloon, especially if the vehicle is overloaded (a truck, say) or driven at high speeds for an extended period of time.
On the other hand, under-inflated tires are more insidious because people rarely over-inflate their tires while under-inflated tires are commonplace — mainly because tires, air valves (and wheels) commonly leak air. Also, the condition often goes unnoticed. A tire has to be really low — maybe even close to flat — before it’s visually obvious. Meanwhile, you’re driving around on a tire (or tires) 5, 10 or even 20 psi below the recommended pressure — which can lead to weird handling/poor braking, even a sudden failure due to the heat build-up (see: Ford-Firestone).
An extra quart in the crankcase? Or down a quart?
Running a quart low is far less potentially damaging than running a quart over. Reason? Excess oil in the crankcase is more than the engine was designed to hold — and that oil has to go somewhere. What happens is it gets turned into a foamy froth as the engine’s reciprocating parts churn it around. This foamy frothy oil is less able to lubricate vital parts — and can also end up where it shouldn’t, which in a modern emissions controlled car can lead to other (expensive) problems.
On the other hand, most engines will not be harmed if run a quart or so low for a little while. Since all internal combustion engines use a certain amount of oil during normal operation, it’s expected the level in the crankcase will occasionally be less than “full.” The engineers who designed the engine know this — and designed in an extra margin of total oil capacity for just this reason.
The key thing is to be sure to check the oil level at least every couple of weeks. You don’t want to run below the safe margin — typically about a quart less than “full” — which could result in catastrophic engine failure and a massive repair bill.
Drive off right away — or “warm it up” a little first?
One of the biggest differences between “old” cars (those built before the widespread adoption of electronic fuel injection and computer controls in the mid-late 1980s) and “modern” cars is the warm-up protocol.
Older cars without computers (and with carburetors) needed more cold-start hand-holding. It often took a couple of minutes for the choke to turn itself off and the engine to settle into a comfortable (and stall-free) idle. With modern cars, warm-up happens much faster. Most owner’s manuals say it’s fine to drive away normally within 30 seconds or so after start-up.
Nonetheless, you’ll do your (modern) car a favor by taking it easy for the first 10-15 minutes of driving. Wear and tear is still highest when the engine is cold — even if a modern car’s cold start drivability is much better than an old car’s. By avoiding full throttle starts and being gentle until the entire car — engine, transmission, brakes, etc. — have reached full normal operating temperature you’ll help the car last longer.
Tip: If your vehicle has a manual transmission, let the clutch out (with the transmission in neutral) during that initial 30 seconds after start-up. This will circulate gear lube inside the transmission, coating all the critical parts. Reduced wear and tear — and easier shifting — will be your reward. (Automatic transmissions do this automatically, whenever the engine is running and no matter what gear the vehicle is in — so you don’t need to do anything.)
Ride the brakes — or “gear down”?
Descending a steep grade, which is smarter: Using the brakes to keep the car from picking up too much speed? Or downshifting to a lower gear and using engine braking to achieve the same thing?
Replacement brake pads (and even calipers and rotors, etc.) are a lot cheaper, usually, than a new clutch or rebuilt transmission. So the argument from the economical perspective is: Use the brakes — and save the wear and tear on your clutch/transmission.
On the other hand, how much is your life worth? Riding the brakes for extended periods on steep downhill grades may heat them up to the point that braking power starts to fade. If that happens, you won’t be able to stop the car as quickly (maybe not at all) if an unexpected emergency situation comes up. Cars with high-performance brake pads/systems are more fade-resistant, but they’re not immune from this problem, either.
So, it’s more sensible to put the transmission in a lower gear to keep the car from building up too much speed on extended downhills.
If your car has an automatic, going from “OD” to “D” (or just turning off the overdrive by pushing the button, if applicable) is usually sufficient, but you can always go down one more to 3 or even 2 if need be. With a manual, downshift to the gear that maintains the speed you want without your needing to ride the brakes.
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Guadalautern tell us what your experience is. I have never seen any corrupt traffic enforcement so tell us how it really is and what happend to you and what constitutional laws that were broken on you and where do you think that all of the dollars go to.
Guadalautern you are on the wrong site if you are telling drivers here to drive slow the first 10-15 minutes.
For one thing the majority of commutes are 15 minutes or less. Second, it does not take that long to warm up an engiine unless it is 25 below zero.
Thanks for generalizing.
Some people here understand how mechanical devices work, and they have respect for them. So full load is only utilized after all mechanical components are ready for their duty cycle.
Since jobs are disappearing [by design] due to globalization, off-shoring, out sourcing, legal & illegal immigration, people are having to drive farther to their place of work. (if they still have a job, seeing as real unemployment is still above 22%)
Depending on your vehicle, it can take 15 minutes of idling to reach full warm up temperature (thermostat stabilized open) at 0 F.
Many new vehicles are designed to hasten catalytic converter operation, so they keep the engine speed elevated when cold started. (I remember the Mazda6 3.0 V6 revving to just over 2K and holding circa 1500rpm)
Thanks George for showing your ignorance. Only you would idle your car for 15 minutes.
Oh, I am sorry. I like to have my oil reach full operating (self-cleaning) temperature before shutting of the engine.
What about personal vehicles with commercial oriented diesel? Cummins, Powerstroke, Duramax.
Do you know how many quarts of oil these hold? What about coolant? talk gallons, not quarts. They may take 30 minutes to warm up at -25F (assuming that it was plugged it, and the radiator opening is covered)
Heck, when it is really cold (-40), those diesel engines are not switched off, because they would take an hour of idling to warm up, but that isn't the real issue. Engine wear-most of the engine wear occurs upon cold/dry startup.
No George I do not care how much fluids those vehicles hold. Only you would care about other vehicle fluid capacities. What a great hobby you have. I guess most drivers would not own a personal vehicle if you can not drive it for 15 minutes. I guess that is why I get 40 mpg and you get what 5 spending all of your time idling? I get on the road within 15 seconds after I turn it on unless I am worried about the windshield freezing up and I could not see. My vehicles seem to last well past 200 thousand miles. I have not got rid of a vehicle because the engine went bad either. Engine oil does not take minutes to get pumped into the engine. That is why we have oils like 5W/20 for most newer cars.
If you are so worried about engine wear on startup then I guess you would leave the engine off all the time or keep it running to keep the oil flowing.
Funny how I and millions of others have had no problems. You must sill be driving an old car with your million miles on the engine.
I guess in your world, there is no such thing as specific heat capacity.
I never got around to purchasing an engine pre-oiler.
Only an idiot would worry about specific heat capacity in an engine when if you buy a modern car it just does not matter. If you drive a vehicle in severe conditions all the time then you worry more about if the vehicle can handle the environment but the majority of modern vehicles can handle 99.999% of our driving conditions in the US. This site is for the most part not about large trucks so we probably do not need to worry about the special things that they may need to do to keep them running every day. Truckers have their own sites for vehicle information.
This site is more about idiots like you trying to get people to break laws and drive as fast as you can.
Fantastic article, Eric, you've really stepped up your game. Well done.
30 Seconds is a bit long to wait before driving away with a cold motor – no matter what age the vehicle. Once the oil pressure light goes out or the oil pressure gauge indicates pressure, it is no problem to drive as long as one doesn't rev his engine over about 2000 RPMs (less for a Diesel). 10 – 15 minutes wait-time before putting stress on a motor is about right because the oil should be pretty warm by this time. Normal water temperature is reached much more quickly.
Fantastic article, Eric, you've really stepped up your game. Well done.
Fantastic article, Eric, you've really stepped up your game. Well done.