Know-how.

Look at the radiator cap. It should be the one your TM calls for. Just any cap won't do. The pressure rating of the cap is vital. Too low a rating lowers the boiling point of your coolant. Too high builds up pressure that'll pop radiator seams or blow hoses.

Hoses need to be touched as well as looked at. They must withstand heat, pressure and vibration. They' re rubber, so they rot, harden and crack with age. You need both eyes and hands to detect bad hoses. Report any bad hoses that show these signs:

Check the radiator. Look for leaks on the top and bottom tanks and the front and back of the core.

Leaks may not show up when your engine is cold, so look for rust and odd-colored dribbles where coolant has leaked and dried.

Later, when you've got the engine running at operating temperature and pressure, check those places again for wet spots. Use a flashlight during both inspections.

Finally, take the radiator cap off. If the cooling system is hot, open the filler cap slowly until all pressure is gone. Use a rag or glove to protect your bare hand from the hot cap.

The coolant should be at least over the top of the core. It should be almost clear and colored by the antifreeze.

If your coolant is muddy-looking or has bits of junk in it, your vehicle's cooling system needs draining--flushing-even cleaning. So report it!

If you see a rainbow of oil slime on top of the coolant, you've probably got a leak inside the engine. Exhaust gas or oil is getting into your cooling system. Pull the crankcase dipstick and check for water in the oil. Little blobs will show on the dipstick. Either way, report it.