Technical Car Experts Answers everything you need: How to troubleshoot heater core?

Saturday, June 25, 2011

How to troubleshoot heater core?

It is important to understand how the heater works in your car before you can begin to try to diagnose why it is not working. The part that transfers heat into the passenger compartment is called a heater core. A heater core can be thought of as a miniature radiator. The car engine's coolant flows through the heater core while the fan (also called a blower), blows air through the heater core fins. When air blows through the heater core fins, it is warmed.------------ Now for troubleshooting:----

Start by checking the coolant. As we already said coolant is what warms the heater core. So if the coolant is low, there may not be a sufficient amount of warmth to transfer heat to the air in the passenger compartment.Once the coolant is full, feel the heater hoses that go through the firewall. With the engine at normal operating temperature, BOTH of the heater hoses should be hot to the touch. If only one is hot, this indicates there is is a blockage in the heater core or there is air trapped in the heater core.One hose hot, one cold, points to a plugged heater core.If this is the case,try flushing the heater core.There are no valves in the heater core; it is free flow at all times.Also check the head gasket. just because there is no water coming out of the exhaust dos,nt mean the head gasket is ok.How much pressure is in the system?.Are the water hoses very hard when the engine is hot?.......air in the system will stop the heater from working.------------Also try this procedure to clean the block in the heater core.If there is any:--- Put in a cleaner, Prestone, and drive car few hours.Then check if nNo success. Then get cleaner made by Gunk.You can get it from any local auto part store. Drain heater core, leave both heater hoses attached to the heater. Remove other ends of both hoses from the tubes on the thermostat housing and raise these ends above the heater core. Pour Gunk cleaner in one hose and add water until cleaner started to come out other hose. Leave this sit 4 hours and back flush heater core in both directions. Next back-flush block and radiator in both directions. Water should come out of tube on the thermostat housing that has a hose attached to the outlet of the heater core.If not coming then Flush water directly into this tube about 15 to 20 times and you will hear a thud of water coming out.. Back flush block and radiator again and this time water should out the tube previously blocked. But if problem is same and no difference.Then is faulty heater core.Its causing the problem and it needs to be replaced.Also check the radiator,if its blocked then get the radiator back flushed too.

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