A leaking radiator hose will cause your car to lose coolant and the engine to overheat. But you can usually fix the leak temporarily so that you can drive to a garage.
Let the engine cool thoroughly. The coolant is probably well above boiling point, and opening the radiator or expansion tank cap prematurely will release a scalding geyser.
When the cap is cool to the touch (20 to 30 minutes), place a thick cloth over it and turn it counter clockwise until you hit a stop - about a quarter of a turn - and then let go. This will allow the remaining pressure to be released, and the cloth will catch any steam and hot coolant that escapes.
If the leak is at the hose connection, re-tightening the clamp may solve the problem easily. If not, look for the leak in the hose and patch it, using insulating tape or even tied rags.
Then start the engine and fill the radiator with plain water. Replace the radiator or expansion tank cap, but tighten it only to the first stop so that pressure won't build up.
Put the heater on High (see OVER-HEATED ENGINE) and drive at moderate speed to a garage, where you can get the leak repaired permanently.
Replacing a hose
You may find that the clamp is stuck to the hose (or the hose to the hose neck) by scale or rust. Don't try to pry it loose - you could damage the connection at either end, causing another leak.
Put some penetrating oil on the clamp.
If it's a squeeze or spring-type clamp, squeeze and wiggle it with pliers. It should come loose.
For a screw-type clamp, insert the tip of a screwdriver beneath the clamp and gently work it around.
If the hose is stuck to the hose neck, twist it from left to right until it is released. If that doesn't work, cut the hose off beyond the hose neck, slit the rest of the hose lengthwise, and peel it off.
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