Niagara Gazette

October 10, 2013

TOM'S CORNER: How often should shocks and struts be changed?

By Tom Torbjornsen
Niagara Gazette

Niagara Gazette — RON FROM DELAWARE: I own a 2008 Toyota Solara. How often should the struts be changed? And are struts a lifetime part?

TOM: Strut life varies with the type of vehicle, how the vehicle is driven, and the environment in which the vehicle is driven. Have the struts inspected by a qualified shop to determine if they need replacement. Struts do not last the lifetime of the car. As a matter of fact, they are considered a wearable item (an item that wears with age).

Ron asks a couple of good questions. Let’s take a look at other questions I get related to shocks and struts.

What do shocks and struts do? Shocks and struts are designed to dampen spring oscillation and keep the tire on the road surface in order to prevent choppy (cupped) wear on the tires.

How to inspect struts and shocks: The proper way to inspect a shock or strut is to lift the vehicle in the air and directly inspect the shock or strut body. Evidence of oil leakage on the body of the shock or strut indicates the need for replacement. Another way to check them is to perform a bounce test. Place your knee on the bumper and start bouncing the vehicle. Once you get it going, step away and watch how the body reacts. It should bounce half a time and settle to a stop. If it keeps bouncing, the shocks or struts are bad a need replacing.

Are struts a lifetime item? No, shock and struts are wearable items and go bad with use. Some replacement shocks or struts come with a lifetime guarantee, but I’ve never seen one continue to deliver proper service the life of a vehicle.

What is the recommended replacement interval for shocks and struts? They should be replaced every 50-70K miles OR when the shocks & struts fail a visual inspection, a bounce test, or tires show choppy wear patterns.

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ALAN FROM NEW JERSEY: Why do my car’s belts squeal all the time? I own a 2006 Ford Focus with a 2.3 liter 4 cylinder engine. I have replaced the belts three times in the last three months and they still squeal, especially when the A/C is on. I am tired of replacing belts, so what else could be wrong?

TOM: Your car has only one drive belt called a serpentine belt. Check for a worn, glazed, or torn belt or a worn automatic belt tensioner.

Note that Alan keeps referring to “belts.” His car only has one belt that drives all the components, the serpentine belt.

Why is it called a serpentine belt? This type of system utilizes one long belt to snake its way throughout the pulley system driving all the components, hence its name Serpentine (snake).

How do you adjust the belt tension? Carmakers came up with a brilliant solution to this problem. They realized that if they stretched the belt out to the required length needed to drive all the components, then they would have to come up with a way to automatically adjust the belt as it stretched out with wear. The solution? An automatic belt tensioner. This device is a spring loaded idler pulley that rides against the back of the belt and keeps it adjusted to perfect tension at all times. As in the case of Alan’s car, these tensioners wear out over time and must be replaced. How do you know that the tensioner is worn out? The belt with squeal incessantly, especially when a load (such as the air conditioner) is added to the system.

How do I know when to replace the belt? A simple visual inspection of the belt will show signs of age, which include glazing, torn ribs, excessive wear, cracking, or fraying. Average serpentine belt life? 35 – 50 thousand miles.

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MARK FROM PHILADELPHIA: My indicator gauge on my ‘04 Mazda Tribute does not indicate that the engine is hot. However, it smells hot after I’ve been driving for a short time, and I see a little smoke coming from under the hood. What would be causing this?

TOM: The smell could be a result of a coolant leak, oil leak, or transmission fluid leak burning on a hot exhaust. In short, lots of things could cause this condition. Get it into a shop and have it checked out immediately.

Cars tell us when they have a problem; we just have to pay attention. Mark’s car is expressing symptoms of a leak. So how do we track it down?

• Check fluid levels: Smoke from under the hood is a key symptom. First, check all the fluid levels (oil, transmission, coolant, brake fluid, and power steering fluid). If any of the fluids are dramatically low, start the diagnostics there. Get the car up on a lift and check underneath for engine oil, coolant, or transmission oil leakage. The leak may evade you. If this is the case, there are lots of tests you can perform to track down the source.

• Cooling system test: The best way to find a leak in the cooling system is a pressure test. The goal of the test is to force a leak at the weakest point in the system. Air pressure is applied to the cooling system with an air pump or regulated source (make sure to keep pressure below 14 PSI to avoid causing more damage). If there’s a leak in the radiator, water pump, gasket, or a hose, it will show up under pressure. Sometimes a system will lose pressure but it will not display an external leak. This tells you that there’s probably a leak internally, such as a blown head gasket or cracked/warped cylinder head.

• Dye testing: Sometimes a fluid leak just refuses to show itself, so you have to get tough with it. It’s time to pull the dye testing system out. During the procedure, a vial of fluorescent dye is added to whatever system/component is the suspected culprit. The vehicle is driven in order to circulate the dye through the system. At this point, the tech shines an ultraviolet light on the suspect and if it is guilty of leaking, it will show up as a bright color. This test is very effective in tracking down a rouge leak.

’Til next time ... Keep Rollin.

"America's Car Show" with Tom Torbjornsen airs 7:30 p.m. Wednesday, 9 a.m. Thursday and 11 a.m. Saturday on WBBZ-TV.