top of page


1A. Motivation

    Oil Level 

I am well aware that checking the oil level can quickly become monotonous, particularly on (most) newer engines, because that dipstick always seems to register full or nearly so during the first several years of the car’s life . . . Need some motivation ? 

I can’t begin to count the number of customers who have rolled in for an oil change around 40K with absolutely no oil on the dipstick. Here stands a once beautiful car, not even close to being paid off, that is destined to burn oil down through the years  ! Then that plaintive wail goes up, “But how could this happen ? The oil light never came on!” The answer is that there are very few cars on the road today that will inform the driver that the engine’s oil level is low. (Those that do are predominantly higher-end models.) The oil light indicates a loss of oil pressure, not a loss of oil. When that light does comes on, you’d better be looking for a place to pull over, because it’s telling you that the oil pump can no longer scavenge enough oil to lubricate the motor. In all probability, your oil level has been low for weeks. (No wonder they call it an idiot light . . .)

As with the oil light, so too with the oil gauge. These register oil pressure, which only corresponds to oil level when it is already too low to adequately lubricate the piston rings.

Auto manufacturers could build oil level sensors into every engine. We do, after all, have bluetooth capabilities and heated mirrors. So why don’t they? The cynical response is that after the car is sold, the manufacturer can’t make a dime on it unless you buy their parts. Engines have lots of parts. 

So don’t get complacent! Develop good habits, then stick to them. Lapsing into neglect can spell BIG TROUBLE, particularly in the 30,000 to 40,000 mile range – the time in an engine’s life when oil usually starts to disappear.

    Coolant Level 

Overheating the engine is one of those catastrophic mistakes that is almost always completely avoidable. A monthly inspection of coolant level coupled with routine, periodic checks of the temperature gauge virtually eliminate the possibility of trouble. Unfortunately, all those miles of trouble-free driving stretching out behind you have the same effect as continuously finding the crankcase full of oil.

This might help: Once an engine overheats, it takes no more than five to ten minutes of additional driving before the head gasket blows. Minimum cost to repair? At least a thousand bucks. Continued driving can lead to many thousands more of additional engine damage, culminating in power loss as the engine begins to lock up.

If you ever see the temperature gauge climbing toward the red range, turn on the interior heat full blast, pull over, turn off the engine, then turn to § 1, p.149.
Do Not Remove the Radiator Cap!

    Tire Pressures

Every car manufactured for the US market since 2007 has a tire pressure warning system. I’m sure they’ve prevented many accidents. I’m also certain that their presence offers an assuring sense of security  to a great many of us: 

“No need to bother with checking tire pressures. Remember last fall? That warning light came on as soon as it turned cold. We’ll know if they’re low.” 

All of which assumes the system continues to work and that it’s properly calibrated. It also means that you’re willing to settle for tires that might be under-inflated by as much as 25%, the point at which your least-inflated tire will trigger the dashboard warning light (Fig. 6 - 1). Assuming that a tire’s correct inflation is 32 psi (pounds per square inch), a 20% loss means that tire will be carrying less than 26 psi. 

Even moderately under-inflated tires produce increased tire wear, decreased fuel economy and consequent higher pollution. Tires running 10 psi or more below their suggested inflation are extremely dangerous when cornering, particularly when swerving to avoid hitting a pothole. Severe under-inflation can trash a tire in short order. Under-inflated tires usually don’t look like they need attention until they get down around 15 psi, which is damned near flat!

Over-inflation is not addressed by tire pressure sensors. Excessively high pressures dramatically reduce traction – particularly noticeable on wet roads. Hot weather or high-speed driving can produce blowouts. And just like severe under-inflation, too much pressure can quickly ruin a tire.

Significant over- or under-inflation exerts undue stress on the plies (layers) of the tire and their bonding one to the other. This type of abuse creates ply separations just as easily as smacking a pothole. For a deeper discussion, see § 1 through § 4, pp. 317-325.

bottom of page