The recommended coolant for all vehicles covered by this guide is a 50/50 mixture of ethylene glycol and water for year-round use. Choose an aluminum compatible, good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors, along with acid neutralizers.
See Figure 1
Any time you have the hood open, glance at the coolant recovery tank to make sure it is properly filled. Top off the cooling system using the recovery tank and its markings as a guideline. If you top off the system, make a note of it to check again soon. A coolant level that consistently drops is usually a sign of a small, hard to detect leak, although in the worst case it could be a sign of an internal engine leak (blown head gasket/cracked block-... check the engine oil for coolant contamination). In most cases, you will be able to trace the leak to a loose fitting or damaged hose (and you might solve a problem before it leaves you stranded). Evaporating ethylene glycol antifreeze will leave small, white (salt-like) deposits, which can be helpful in tracing a leak.
At least annually or every 15,000 miles (25,000 km), all hoses, fittings and cooling system connections should be inspected for damage, wear or leaks. Hose clamps should be checked for tightness, and soft or cracked hoses should be replaced. Damp spots, or accumulations of rust or dye near hoses or fittings indicate possible leakage. These must be corrected before filling the system with fresh coolant. The pressure cap should be examined for signs of deterioration and aging. The water pump drive belt(s) should be inspected and adjusted to the proper tension. Refer to the information on drive belts found earlier in this section. Finally, if everything looks good, obtain an antifreeze/coolant testing hydrometer in order to check the freeze and boil-over protection capabilities of the coolant currently in your engine. Old or improperly mixed coolant should be replaced.
The engine cooling system should be inspected, flushed and refilled with fresh coolant. The engine coolant should be changed initially at 50, 000 miles (80, 000 km), then change the coolant at least once every 3 years or 36,000 miles (48,000 km),. 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.
If you experience problems with your cooling system, such as overheating or boiling over, check for a simple cause before expecting the complicated. Make sure the system can fully pressurize (are all the connections tight/is the radiator cap on properly, is the cap seal intact-). Ideally, a pressure tester should be connected to the radiator opening and the system should be pressurized and inspected for leaks. If no obvious problems are found, use a hydrometer antifreeze/coolant tester (available at most automotive supply stores) to check the condition and concentration of the antifreeze in your cooling system. Excessively old coolant or the wrong proportions of water and coolant will adversely affect the coolant's boiling and freezing points.Check the Radiator Cap
See Figure 2
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. Worn caps should be replaced with new ones.
See Figure 3
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 with a pair of needle-nosed pliers. Be careful; the fins are very soft. Don't wiggle the fins back and forth too much. Straighten them once and try not to move them again.
DRAIN & REFILL
See Figures 4 and 5
A complete drain and refill of the cooling system at 50,000 miles (80, 000km) and afterwards at least every 30,000 miles (48,000 km) or 3 years will remove the accumulated rust, scale and other deposits. The recommended coolant is a 50/50 mixture of ethylene glycol and water for year-round use. Choose a good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors, along with acid neutralizers.
- Raise the vehicle and support it with jackstands.
- Remove the splash shield from the front of the front sub frame and body.
Before opening the radiator petcock, spray it with some penetrating lubricant.
- Place a suitable container under the petcock.
- Remove the reservoir bottle pressure cap.
- Attach a length of rubber hose to the draincock. This will help to direct the coolant flow into the drain pan.
- Drain the existing coolant by opening the radiator petcock.
- Close the petcock and install the splash shield.
- Lower the vehicle.
Determine the capacity of the coolant system, then properly refill the cooling system with a 50/50 mixture of fresh coolant and water, as follows:
- Fill the reservoir bottle with coolant until it reaches the top of the cold fill mark on the bottle.
- Reinstall the bottle pressure cap.
- Select the maximum heater temperature and blower motor speed settings. Position the control to discharge air at the A/C vents in the instrument panel.
- Start the engine and allow it to idle until hot air is coming from the A/C vents.
- If the air discharge from the A/C vents remains cool and the temperature gauge does not move, the engine coolant is low in the engine and must be filled. Turn the engine OFF , allow the engine to cool and add coolant through the reservoir bottle as described earlier and replace the cap.
- Start the engine and allow it to idle. Hot air should come from the A/C vents. The engine coolant temperature gauge should maintain a stabilized reading within the normal range and the upper radiator hose should feel hot to the touch.
- Shut off the engine and allow it to cool.
- If available, install a pressure tester and check for leaks. If a pressure tester is not available, run the engine until normal operating temperature is reached (allowing the system to naturally pressurize), then check for leaks.
- Check the level of protection with an antifreeze/coolant hydrometer.
FLUSHING & CLEANING THE SYSTEM
- Remove the radiator and turn it upside down.
- Using a garden hose inserted in the lower hose location, backflush the radiator making sure the radiator internal pressure does not exceed 20 psi (138 kPa).
- Remove the thermostat, insert the hose into the thermostat opening.
- Turn the hose on high and let the water backflush the engine block.
- Tag and disconnect the heater core outlet hose from the water pump fitting and connect a female garden hose-end adapter in the end of the hose and hold it in place with a hose clamp.
- Connect the garden hose to the hose-end adapter attached to the heater core hose.
- Tag and disconnect the heater core inlet hose from the block and position it so a container to catch the coolant and water can be placed under it.
- Place a suitable sized container under the inlet hose.
- If equipped with a water valve on the heater core inlet hose, make sure the valve is open (no vacuum).
- Turn the water supply on and off several times to loosen sludge and deposits, then turn the full water pressure on and let it run for about five minutes.
- If a water valve is installed in the heater core inlet hose, apply vacuum to the valve vacuum motor to check for proper operation of the valve with proper closure with no water leakage. If there is water leakage, replace the valve.
- Remove the garden hose and the adapter from the outlet hose.
- Connect the heater core inlet and outlet hoses.
- Install the thermostat and radiator.
- Properly fill the cooling system.
- Start the engine and allow it to reach normal operating temperature, then check for leaks.