Q:

My brakes are squealing. Does that mean I need a brake job?

A:

Not necessarily. A certain amount of brake noise is considered "normal" these days because of the harder semi-metallic brake pads that are used in most front-wheel drive cars and minivans. This type of noise does not affect braking performance and does not indicate a brake problem. However, if the noise is objectionable, there are ways to eliminate it.

Brake squeal is caused by vibration between the brake pads, rotors and calipers. Pad noise can be lessened or eliminated by installing "noise suppression shims" (thin self-adhesive strips) on the backs of the pads, or applying "noise suppression compound" on the backs of the pads to dampen vibrations. Additional steps that can be taken to eliminate noise are to resurface the rotors and replace the pads.

Some brake pads have built-in "wear sensors" that produce a scraping or squealing noise when the pads become worn. In any event, noisy brakes should always be inspected to determine whether or not there’s a problem. And don’t delay! If the pads have worn down to the point where metal-to-metal contact is occurring, your vehicle may not be able to stop safely, and you may score the rotors or drums to the point where they have to be replaced.

Q:

Why should I change the transmission fluid and filter and how often?

A:

Most owner’s manuals say it isn’t necessary. Yeah, right. That’s why transmission shops are making a fortune replacing burned out automatic transmissions.

For optimum protection, change the fluid and filter every 30,000 miles. Fluid and filter change is recommended more often if the vehicle is being used for towing, heavy hauling, or heavily driven.

Why ATF Wears Out:

An automatic transmission creates a lot of internal heat through friction: the friction of the fluid churning inside the torque converter, friction created when the clutch plates engage, and the normal friction created by gears and bearings carrying their loads.

As a rule of thumb, every 20 degree increase in operating temperature above 175 degrees F. cuts the life of the fluid in half!

On most vehicles, the automatic transmission fluid is cooled by a small heat exchanger inside the bottom or end tank of the radiator. Hot ATF from the transmission circulates through a short loop of pipe and is thus "cooled." Cooling is a relative term here, however, because the radiator itself may be running at anywhere from 180 to 220 degrees F.!

Q:

I feel a high speed shimmy in the steering wheel, what’s causing it?

A:

A high speed shimmy is usually caused by a wheel that’s out of balance or a bent wheel. The first thing to check for would be a bent wheel. If it is bent, the wheel needs to be replaced.

WARNING: Although some people claim they can straighten bent wheels, doing so is risky -- especially with aluminum alloy wheels. Replacement is the safest option (but also expensive).

If you don’t see any sideways movement in the wheel, it doesn’t necessarily mean the wheel is straight. There may be just enough sideways runout to cause a shimmy, but not enough to see. If the wheels seem to be straight, have the balance of both wheels checked (or rebalanced). If that fails to cure the shimmy, you may have some kind of tire problem due to defective belt alignment or tire construction. Other causes may include loose or improperly adjusted wheel bearings, insufficient caster alignment (check and readjust alignment as needed), or a worn steering damper (on trucks or other vehicles equipped with a steering stabilizer).

Q:

My coolant system keeps loosing coolant, but I don’t see any leaks. Where is It going?

A:

You probably have an "internal" coolant leak inside your engine. The coolant is escaping into the combustion chamber or crankcase through cracks in the cylinder head or block, or through a leaky head gasket.

In rare instances, coolant may also leak into the automatic transmission fluid cooler if one is located inside the radiator. But usually when automatic transmission fluid leaks into the coolant it means the line is leaking.

Pressure testing the cooling system is necessary to diagnose an internal leak. A "cylinder leak-down test" can tell a mechanic if the coolant leak is in the combustion chamber. But to pinpoint an internal leak, it is usually necessary to remove the head(s) from the engine. The head may then be pressure tested and/or checked for cracks using special equipment.

If a leaky head gasket is the culprit, replacing the gasket may only temporarily cure the problem if the head or block is warped. The mating surfaces on both the head and block should be checked for flatness and resurfaced if necessary to restore flatness for a proper seal.

Q:

How often should I change my antifreeze?

A:

For "ordinary" antifreeze, the vehicle manufacturers generally recommend coolant changes every two to three years or 30,000 miles. Others say it’s not a bad idea to change the coolant every year for maximum corrosion protection -- especially in vehicles that have aluminum heads, blocks or radiators. But such recommendations may soon be obsolete. Several antifreeze suppliers have just recently introduced "long life" antifreeze formulations that claim to provide protection for four years or 50,000 miles.