Leaking heater hoses are very rare; leaking head gaskets are very common. Neither one is a do-it-yourself project. The heater hoses enter the passenger compartment behind the engine where there is almost no room to work unless the car is on a hoist. Even then it's a lot of frustration. The head gasket is a day-long job for a trained mechanic. There's too many things that can go wrong if you don't know what to watch out for.
If you want to attempt the heater hose, and you're sure that's what it needs, each end will have a clamp that is loosened usually with a flat blade screwdriver. Slide the clamps away from the fittings, then, to remove the hose, which will be stuck, use a razor blade to cut the hose length-wise for about two inches, then carefully peel the end open. If it's attached to a cast metal part on the engine, you can just twist it by hand to loosen it, but the fitting on the heater core, (firewall), will be brass or plastic. Twisting the hose here can break the soldered pipe connection on the heater core, (get the big wallet out), or can crack a plastic pipe. GM cars and minivans have a lot of trouble with plastic tubes becoming brittle with age and snapping off. Repair of heater cores usually involves removing the steering column and dash board. It's an expensive job.
Take the old hose to the parts store. They will sell you the exact length you need from a bulk roll, in the correct diameter. In some cases, mostly with GM cars, one end of the hose is molded to form a sharp curve. Regular bulk hose will kink in these applications so you will need to order that type of hose right from the dealer. Slide the new hose onto the nipples, then position and tighten the clamps. Don't get carried away with the tight part of it. Too much twisting force could snap a plastic fitting. The system only gets as high as 16 psi. In the unlikely event the hose is hard to slide on, a little silicone spray lube makes rubber parts slide over metal parts REAL easy, and it evaporates very quickly.
Refill the system with a 50/50 mix of water and antifreeze. Don't forget to fill the overflow reservoir too. Start the engine and let it warm up. Keep an eye on the temperature gauge. If it starts to over heat, there's an air bubble that hasn't burped out yet. First speed the engine up a little. The extra force from the water pump might slosh hot coolant onto the thermostat so it opens. (Thermostats don't open in hot air; it has to be liquid). If the thermostat opens, the temperature gauge will drop to "cold" when the cold coolant from the radiator enters the engine. The air should be burped now. If it continues to run hot, stop the engine and let it cool for an hour or two. The air bubble will shrink and may burp out the next warm-up cycle. If that doesn't work, there are things that can be temporarily removed to get the air out. You can also try driving it before it gets fully warmed up. The sloshing coolant might trigger the thermostat to open. After the air is bled out, you'll probably have to add coolant to the reservoir. There will be markings on the side to show how high to fill it.
Tuesday, April 28th, 2009 AT 3:47 AM