Cooling system maintenance
See Figure 10

At least once a year on glycol-based coolants, the engine cooling system should be inspected, flushed, and refilled with fresh coolant. If the coolant is left in the system too long, it loses its ability to prevent rust and corrosion. If the coolant has too much water, it won't protect against freezing.

Silicate free coolants such as DEX-COOL® can go for 100,000 miles [160,000 km] or 5 years, whichever comes first. However, if you add a silicate coolant to the system (even in small amounts) premature engine, heater core or radiator corrosion may result. In addition, the coolant will have to be changed sooner (12,000 miles [19,300 km] or every year, just like other vehicles not using DEX-COOL® or other Silicate-free coolant).

The pressure cap should be checked for signs of age or deterioration. The fan belt and other drive belts should be inspected and adjusted to the proper tension. If a belt is cracked, frayed along the edges, or shows signs of peeling, it should be replaced before it fails and causes problems that are more serious.

Leaves, dead insects, and other debris should be removed from the surfaces of the radiator and the air conditioning condenser so air can get through. Hose clamps should be tightened, and soft or cracked hoses replaced. Damp spots or accumulations of rust or dye near hoses, water pump, or other areas indicate possible leakage, which must be corrected before filling the system with fresh coolant.

Figure 10 Check these components of the cooling system: Coolant level (1); Radiator cap (2); Radiator hoses (3); Drive belts (4); Clean radiator (5); Change coolant (6); Thermostat (7).

Checking coolant level

Never remove the radiator cap under any conditions while the engine is hot! Failure to follow these instructions could result in damage to the cooling system, engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the radiator, use extreme care whenever you are removing the radiator cap. Wait until the engine has cooled, then wrap a thick cloth around the radiator cap and turn it slowly to the first stop. Step back while the pressure is released from the cooling system. When you are sure the pressure has been released, press down on the radiator cap (still have the cloth in position) turn and remove the radiator cap.

Once a month or every 1,000 miles (1,600 km), whichever comes first, check the level of the coolant in the radiator. If you do a lot of hard driving or trailer pulling, check more often.

On vehicles without a coolant overflow system, the coolant level should be checked on a cold engine. If there is a chance the engine is hot, cover the radiator cap with a heavy cloth. Turn the radiator cap to the first stop and let the pressure release. The pressure is gone when the hissing stops. Push down on the cap and turn it all the way around to remove it.

Most late-model vehicles come equipped with a coolant recovery system. They allow coolant that would normally overflow to be caught in an expansion tank; it will automatically be drawn back into the radiator when the coolant cools down. Radiator caps for these systems are not interchangeable. Replace only with the proper cap for the system.

On vehicles without coolant recovery systems, keep the coolant level 1-2 inches (25-50mm) below the filler neck on a cold engine. On vehicles equipped with a coolant recovery system, simply check the level in the plastic tank, located near the radiator. On these types, top off the coolant in the plastic tank, not the radiator. Only when doing a complete refill should you add to the radiator, then the overflow tank.

If the coolant level is constantly low, check for leaks.

Checking the radiator cap
See Figure 11

While you are checking the coolant level, check the radiator cap for a worn or cracked gasket. If the cap doesn't seal properly, fluid will be lost and the engine will overheat. A worn cap should be replaced with a new one.

Figure 11 Check the radiator cap gasket and seal.

Cleaning radiator of debris
See Figure 12

Periodically clean any debris-leaves, paper, insects, etc.-from the radiator fins. Pick the large pieces off by hand. The smaller pieces can be washed away with water pressure from a hose.

Carefully straighten any bent radiator fins. Be careful, the fins are very soft.

Figure 12 Keep the radiator and air conditioning condenser clear of debris, bugs and leaves.

Drive belts

Modern drive belts don't show their age

On today's vehicles, it's very difficult to tell the difference between an automotive drive belt with 50,000 miles (80,450 km) of wear, and another belt with 10,000 miles (16,090 km) of wear. A basic change in engine belt construction -- one that produced a longer-lasting belt -- also makes it difficult to spot indications of belt wear.

Virtually all automotive drive belts produced in the U.S. and Europe are made without a cover. These "bandless" belts don't show wear like their predecessors. Although bandless belts are designed to outlast banded belts on similar drives, they provide no early warning of failure.

There are two main causes of drive belt failure. The most common is fatigue of the load-bearing, tensile cords leading to belt failure from the inside out. Tensile cord failure is due to a gradual weakening of the tensile cords that results from a combination of side stress, bending stress, and centrifugal force imposed on the belt as it travels around the pulleys.

Because this type of failure takes place inside the belt, there is no easy way to determine when the belt is about to break. Statistics show the chance of drive belt failure on an average vehicle goes up sharply after four years.

For this reason, many drive belt manufacturers recommend that all engine drive belts be replaced on a four-year basis.

In this way, the replacement can be done at the vehicle owner's convenience, rather than on an emergency basis.

The other major cause of drive belt failure is improper tension. This causes the belt to slip as it travels around the pulleys, generating heat build-up. Excessive heat eventually causes the rubber compounds in the belt to break down and crack, leading to belt failure.

Indicators of belt tension problems include:

• Belt squeal, especially on the fan or power steering drives.
• Battery discharge sometimes caused by a slipping alternator belt.
• Excessive sidewall wear that allows the belt to ride lower than normal in the pulley grooves.
• Absences of overcord (the belt's top protective covering).
• Excessive cracking, or rib chunking (pieces of the ribs breaking off). Keep in mind that serpentine belts do tend to form small cracks across the backing. If the only wear you find is in the form of one or more cracks across the backing and NOT parallel to the ribs, the belt is still good and does not need to be replaced.

In addition, small engine compartments on today's vehicles make belts more susceptible to heat and contamination from petroleum products. High temperatures can cause belts to dry, harden and crack. If a belt becomes oil soaked, it cannot grip the pulley. Petroleum products also break down the rubber compounds in the belt.

The best way to check belt tension is with a tension gauge. Because of smaller engine compartments and shorter belt spans between pulleys, the old finger deflection method of checking tension is not as accurate.

Belt inspection
See Figures 13, 14, 15, 16 and 17

DO NOT use belt dressings in an attempt to extend belt life. Belt dressing will soften the belt, causing deterioration. Oil or grease contamination on the belt or pulleys will have the same effect. Keep the drive belt system clear of oil, grease, coolant or other contaminants.

Accessory drive belts are of two types, V-belts (conventional, cogged and multi-ribbed) and serpentine (multi-ribbed) belts. A V-belt rides in V-shaped pulleys to rotate various accessories, such as the power steering pump, air conditioner compressor, alternator/generator, water pump, and air pump. Only the inside of a V-belt is used, unlike a serpentine belt which utilizes both sides. V-belts typically operate one or two accessories per belt, whereas a single serpentine belt can power all of the accessories. V-belts and a few serpentine belts require periodic adjustment because the belts are under tension and stretch over time. Most serpentine belts utilize an automatic belt tensioner that constantly provides the proper tension to the belt.

V-belts

Many vehicles utilize one or more V-belts to drive engine accessories (such as the alternator, water pump, power steering pump or A/C compressor off the crankshaft).

V-belts should be checked every 3,000 miles (4,800 km) or 3 months for evidence of wear such as cracking, fraying and incorrect tension. Determine the belt tension at a point halfway between the pulleys by pressing on the belt with moderate thumb pressure. The belt should deflect about 1/4 inch (6 mm) over a 7-10 inch (178-254 mm) span, or 1/2 inch (13 mm) over a 13-16 inch (330-406 mm) span. If the deflection is found too much or too little, perform the tension adjustments.

Figure 13 here are typically three types of accessory drive belts found on vehicles today.

Figure 14 An example of a healthy drive belt

Figure 15 Deep cracks in this belt will cause flex, building up heat that will eventually lead to belt failure.

Figure 16 The cover of this belt is worn, exposing the critical reinforcing cords to excessive wear.

Figure 17 Installing too wide a belt can result in serious belt wear and/or breakage.

Serpentine belts
See Figures 18 and 19

Many late model vehicles utilize one ribbed, serpentine belt to drive engine accessories, such as the alternator, water pump, power steering pump or A/C compressor off the crankshaft.

The serpentine belt and pulleys should be inspected every 3,000 miles (4,800 km) or 3 months for evidence of wear such as excessive cracking (on serpentine belts, some cracking is normal), fraying, incorrect alignment and incorrect tension. Proper maintenance of the belt and pulleys can extend normal belt life.

Figure 18 Serpentine drive belts require little attention other than periodic inspection or replacement.

Figure 19 When checking the serpentine belt, be sure it is properly seated in each of the pulleys.

1. Visually check the belt for signs of damage. Routine inspection may reveal cracks in the belt ribs. These cracks will not impair belt performance and are NOT a basis for belt replacement. HOWEVER, if your inspection reveals that sections of the belt are missing, the belt must be replaced to avoid a possible failure.
2. Visually check the belt for proper routing (when compared with the engine compartment label). Make sure the belt is fully seated on all pulleys.

Radiator hoses

Inspection
See Figures 24, 25, 26 and 27

Upper and lower radiator hoses, along with the heater hoses, should be checked for deterioration, leaks and loose hose clamps at every 1,000 miles (1,600 km) or one-month. This may sound excessive, however if you're under the hood it is a good habit to look at your cooling system. A quick visual inspection could discover a weakened hose that might have left you stranded if it had remained unrepaired.

Whenever you are checking the hoses, make sure the engine and cooling system are cold. Visually inspect for cracking, rotting or collapsed hoses, and replace as necessary. Run your hand along the length of the hose. If a weak or swollen spot is noted when squeezing the hose wall, the hose should be replaced.

Figure 24 The cracks developing along this hose are a result of age-related hardening.

Figure 25 A hose clamp that is too tight can cause older hoses to separate and tear on either side of the clamp.

Figure 26 A soft spongy hose (identifiable by the swollen section) will eventually burst and should be replaced.

Figure 27 Hoses are likely to deteriorate from the inside if the cooling system is not periodically flushed.

Never remove the pressure cap while the engine is running, or personal injury from scalding hot coolant or steam may result. If possible, wait until the engine has cooled to remove the pressure cap. If this is not possible, wrap a thick cloth around the pressure cap and turn it slowly to the stop. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, use the cloth to turn and remove the cap.

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