Tuesday, April 3, 2012

Overheating Problem


Here at Bryants Automotive we do all kinds of work on cars, trucks and vans. Lately we have had many vehicles come in with cooling system problems. A typical complaint from customers is that the vehicle is overheating. The customer has noticed this either from the heat gauge on the dash, steam rolling from under the hood.

Initially we sign up customers vehicles for a cooling system inspection. This gives the technician the time to look the entire cooling system over. The technician starts by checking the coolant level when the vehicle has come in and its level of protection (freezing and boiling point). The technician then pressure tests the system to check for leaks. Leaks can be found coming from the water pump, bypass hoses, head gasket, radiator hoses, heater hoses, engine freeze plugs, thermostat housing, and radiator.

This week we had a vehicle come in with an overheating problem. Sometimes vehicles can have more than one problem that is contributing to overheating. On this particular vehicle the technician pressure tested the vehicles cooling system and found a crack in the radiator. After replacing the radiator and filling with coolant he checked the temperature of the coolant as it worked its way through the cooling system. 

He discovered that the coolant was not changing temperature. Typically when the coolant leaves the engine on its way to the radiator it is hot, cools off in the radiator and makes its return trip back through the engine.  He deduced that one of two things was happening.That the thermostat was stuck closed (a thermostat stops coolant from flowing until reaching optimum working temperature for the motor where it then opens to let coolant freely pass through the cooling system). Or that the water pump was not working correctly.  He replaced the thermostat and was still having the coolant flow problem.

The next step was to remove the water pump and inspect the impeller. Essentially the impeller pushes the coolant through the cooling system. The water pump is driven (turned) by the car engine with the serpentine belt in this case. Below is a short video that shows the water pump and impeller.


The impeller is NOT supposed to separate from the water pump. With this vehicle the water pump was turning and the impeller was separated from the water pump and not able to do its job. Which is to push coolant through the cooling system. 

After replacing the water pump and filling with coolant we test drove the vehicle. The new water pump is doing its job in the cooling system and the vehicle no longer overheats.

This is a not-so-short description of one cars journey getting fixed here at Bryant Automotive. I hope you are a little more knowledgeable about how your cooling system works on your vehicle. 



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