See Figure 1
The cooling system was filled at the factory with a high quality coolant solution that is good for year-round operation and protects the system from freezing. If coolant is needed, a 50/50 mix of ethylene glycol or other suitable antifreeze and water should be used. Alcohol or methanol base coolants are specifically not recommended. Antifreeze solution should be used all year, even in summer, to prevent rust and to take advantage of the solution's higher boiling point compared to plain water. This is imperative on air conditioned models; the heater core can freeze if it isn't protected.
See Figures 2, 3 and 4
The coolant should be checked at each fuel stop, to prevent the possibility of overheating and serious engine damage. To check the coolant level simply look into the expansion tank.
Simply add coolant mixture to the tank until the upper level line is reached. If the system shows signs of overheating and, possibly, a small leak, you may want to check the level in the radiator when the engine is cold . If the radiator is not full, replace the cap with a new one, as it has lost the ability to retain vacuum or is of improper design for a coolant overflow tank type of system.
Each year, the cooling system should be serviced as follows:
- Wash the radiator cap and filler neck with clean water.
- Check the coolant for proper level and freeze protection.
- Have the system pressure tested. If a replacement cap is installed, be sure that it conforms to the original specifications.
- Tighten the hose clamps and inspect all hoses. Replace hoses that are swollen, cracked or otherwise deteriorated.
- Clean the frontal area of the radiator core and the air conditioning condenser, if so equipped.
DRAIN AND REFILL
See Figures 5 and 6
Coolant should be changed for the first time at 45,000 miles (72,500 km) or three years, whichever occurs first. Subsequent coolant changes should occur every two years or 30,000 miles (45,000 km) whichever comes first.
- Run the engine with the cap removed and the heater on until operating temperature is reached (indicated by heat in the upper radiator hose).
- With the engine stopped, open the radiator draincock located on the right side of the radiator. The drain will take place through the lower isolator.
- Remove the coolant pressure bottle cap and open the thermostat bleed valve.
- Remove the cylinder block bleed drain plug(s) located behind each exhaust manifold.
- Completely drain the coolant, and close all draincocks and plugs hand tight.
- Attach one end of a .250 inch (6.35mm) ID clear hose that is long enough to reach the bleed valve and the thermostat. Route the hose away from the drive belt, pulleys and electric cooling fan. Place the other end of the hose into a clean container. The hose will prevent coolant from contacting the drive belt when bleeding the system during refilling.
- Open the bleed valve.
- Slowly fill the coolant pressure bottle until a steady stream of coolant flows from the hose attached to the bleed valve.
- Gently squeeze the upper radiator hose until all of the air is removed from the system.
- Close the bleed valve and continue filling to the top of the coolant bottle.
- Install the cap on the coolant pressure bottle.
- Remove the hose from the bleed valve.
FLUSHING AND CLEANING THE SYSTEM
A well maintained system should never require aggressive flushing or cleaning. However, you may find that you (or a previous owner) have neglected to change the antifreeze often enough to fully protect the system. It may have obviously accumulated rust inside, or there may be visible clogging of the radiator tubes.
There are two basic means of rectifying this situation for the do-it-yourselfer. One is to purchase a kit designed to allow you to reverse-flush the system with the pressure available from a garden hose. This kit comes with special fittings which allow you to force water downward inside the engine block and upward (or in reverse of normal flow) in the radiator. It will have complete instructions.
The other means is to purchase a chemical cleaner. The cleaner is installed after the system is flushed and filled with fresh water and cleans the system as you drive a short distance or idle the engine hot. In all cases, the cleaner must be flushed completely from the system after use. In some cases, it may be necessary to follow up with use of a neutralizer. Make sure to follow the instructions very carefully. These cleaners are quite potent, chemically, and work very well; because of that fact, you must be careful to flush and, if necessary, neutralize the effect of the cleaner to keep it from damaging your cooling system.
If the radiator is severely clogged, it may be necessary to have the tubes rodded out by a professional radiator repair shop. In this case, the radiator must be removed and taken to the shop for this highly specialized work. You can save money on the job by removing and replacing the radiator yourself, as described in Engine & Engine Overhaul .