Overheating can be caused by factors other than low coolant level (thermostat stuck closed, blocked radiator, malfunctioning fan or failed water pump). If the coolant level isn't low, it's time to visit a mechanic.

It's OK to add just plain water or antifreeze in an overheating, emergency situation. When routinely adding or changing coolant, always use a 50-50 mixture of water and antifreeze.

Overheating is one of the most common breakdowns that autos encounter during the summer season. It happens when the temperature of the coolant exceeds the normal operating temperature range of the engine. Overheating has many causes. Idling under hot weather for prolonged periods can wreak havoc on the cars cooling system, because the water pump doesn't turn fast enough. Thus the coolant is not circulated, as it should be. Sometimes a leak may cause the coolant level to drop thus causing the radiator to overheat. Here are a few pointers for dealing with an overheated radiator:

Turn off the A/C. If the car is not seriously overheating, this will reduce the engine's temperature. The AC evaporator is located in front of the radiator, and it adds heat to the air going to your engine. The hotter the incoming air is, the less efficient the radiator will be.

Turn on your heater (set on highest temperature setting, with blower on highest setting). This will be uncomfortable for you, but it will cool the engine by transferring the heat to the air. Roll down the windows, and remember how 'hot' you'll get if your engine needs replacement!

If you're stuck in traffic, pull over and stop. Unless you're moving, very little cool air reaches the radiator. Open the hood and let the engine cool off. This takes time, so be patient. Use the time to go get the antifreeze.

Check the overflow tank coolant level. If it's empty, the radiator is probably low on coolant.

Check the pressure of the system by wrapping a cloth around the upper radiator hose and squeezing it. If it's still under pressure (hot) it will not squeeze easily. Wait until it does.

Place a large cloth over the radiator cap, and carefully release the pressure. Serious burns can result from the hot coolant. If in doubt, wait until the engine cools completely.

If the coolant is low, start the engine, and slowly add the coolant necessary to fill it up. The engine must be running. Adding coolant to a warm engine can crack the block. By running the engine, the coolant keeps moving and reduces the chances of this type of damage occurring.

Do you have a cracked water pump or just need auto repair?

A water pump has a "weep-hole" on the bottom of the input shaft that purposely leaks coolant when the sealed bearings have been damaged. If this is happening to you get it repaired ASAP! When you run out of coolant you will over-heat and permanently damage your engine.

The signs you need to look out for:
1. Coolant leaking from the bottom of the pump
2. Making rumbling sounds
3. Temperature gauge shows hot or the red light is on

If you see signs of any one of these signs call Skyway Auto Tune NOW! You need to replace your water pump ASAP you have a serious problem.

Water Pump Replacement Procedure
The water pump replacement job begins with draining of the coolant fluid. Next, the multiple rib drive belt or timing belt is removed. Many devices that obstruct access to the water pump fastening bolts need to be removed. Once access to the water pump is possible, its mounting bolts are removed and the water pump itself is removed, along with the gasket that fixes it to the engine block. Then the new water pump is fixed in place and all the rest of the devices are fixed back again in reverse order. The engine coolant is refilled and the coolant system is checked through this operation.

Automotive Cooling System Service - The greatest cause of summer breakdowns is overheating. The cooling system should be completely flushed and refilled about every 24 months. The level, condition, and concentration of the coolant should be checked periodically. (A 50/50 mix of anti-freeze and water is usually recommended.) Never remove the radiator cap until the engine has thoroughly cooled! The tightness and condition of drive belts, clamps, and hoses should be checked by a pro.here at Skyway Auto Tune!

The cooling system has one and only one purpose to remove excess heat from your engine. As your engine burns gasoline, a little less than a third of the released energy goes into mechanical energy to run your car. The rest is converted to heat. Some of that heat is blown straight out the tailpipe, while the rest heats the engine itself. Without a cooling system, the engine would be destroyed by heat within 3 to 30 minutes of startup.

The cooling system works by moving coolant (water plus antifreeze) through the engine, and moving that heated coolant through the radiator, where its heat is transferred to the surrounding air. The cooling system must have enough cooling capacity to cool a car ascending a long, steep mountain road, where the driver might have the gas pedal 2/3 of the way to the floor.

But it must be regulated in such a way that at a steady 40 MPH on a flat road in subzero weather, the engine's temperature is allowed to quickly rise to the manufacturer's recommended temperature (usually about 200 Farenheit, give or take 20 degrees). That recommended temperature should also be maintained when the car goes up a 10 mile 7% grade in 100 degree weather. Such regulation is accomplished by the car's thermostat -- a heat sensitive valve that allows coolant to flow through the radiator at high temperatures, but cuts off that flow at low temperatures.

The water pump sucks cooled coolant from the radiator and pushes it into the engine. The coolant flows through the engine, absorbing the engine's heat. If the thermostat is open, that coolant then flows into the radiator for cooling. As it flows through the radiator, it heats the tubes and fins on the radiator, and that heat is transferred to the air flowing through the radiator. At low speeds that air flow is maintained by the fan, and at high speeds it's maintained by the relative velocity of the vehicle in relation to the outside air.

Meanwhile, a parallel path brings hot coolant from the engine through the heater in the passenger compartment, and back into the water pump. That path is controlled by the heater valve, which in turn is controled by the lever or electronic climate control on the dashboard. The parallel path is not restricted by the thermostat, so passengers get heat even when the thermostat is closed. However, some cars have a mechanism which shuts off coolant through the heater during an overheat, I guess on the theory that you want to maximize flow through the radiator by shutting off the heater. While such a theory might be credible when the cause of overheating is low coolant, it prevents the alert driver from turning on the heater full blast and thereby letting the heater act as a second radiator. Perhaps such a shutoff is a safety feature so there's no way overly pressurized coolant can rupture the heater and spray on the passengers. So if you've had symptom where "the car overheats and then the heater blows cold air", the heater probably has been shut off due to overheat.

The entire system is sealed with one exception. The radiator cap contains a spring which maintains a constant pressure by venting coolant (to the reservoir tank) when pressure rises above its specified value -- typically around 15 PSI. It's normal for some coolant to vent in this way, which is why the reservoir is more full when the car is hot than when it's cold. The radiator cap also allows the vacuum created when the system cools to "suck back" coolant from the reservoir. But in the case of an extreme overheat, vented coolant overflows the reservoir, thereby creating a low-coolant situation and making the overheat even worse.

Looking at the diagram, you see that oil, gasoline, combustion gasses and coolant all flow inside the engine. These materials are kept separate by the head gasket(s). A breached or broken head gasket, or a bent head, allows any or several of these materials to mix. Coolant into the cylinders produces huge clouds of white exhaust (steam) out the tailpipe. Coolant into the oil produces a yellow/white foam or gunk on the oil cap, as well as degrading the oil, possibly past the point of lubricating usefulness. Combustion gasses leaking from the cylinder to the coolant might produce no obvious symptom, but it's an extremely dangerous condition, because it can cause an overheat by any one or more of four different mechanisms:

By forcing excessive coolant out the reservoir, thereby creating a low-coolant situation
By forming a gas bubble around the thermostat's sensor, thereby preventing the thermostat from opening
By heating the coolant to such a degree that the radiator cannot dispense all the heat
By breaking down the coolant's corrosion protection, thereby damaging the water pump or radiator, ultimately causing overheating

It's possible for a broken head gasket to allow combustion gasses into the coolant, without allowing coolant into the cylinders or coolant into the oil or oil into the coolant. In such a situation, the broken head gasket could silently cause overheats. The definitive test for this type of head gasket problem is to test for combustion gasses at both the radiator fill pipe and at the reservoir.

Our goal is to help you prevent major breakdowns and to save you money. We do this by encouraging affordable maintenance when your car needs it. Periodically, it is important to do more than just a fluid top off. A more thorough inspection is needed. Skyway Auto Tune will do this periodically depending on how long and how many miles you have driven since your last cooling system service. We also factor in what your car manufacturer recommends, and the current condition of the cooling system. Additionally, we encourage more frequent thorough inspections after your car has reached 50,000 miles. We back our auto repair and smog shop 100%, but more importantly we back you first on your entire cooling system needs!

Low coolant level is a more common overheating cause than grossly malfunctioning engines, usage beyond capabilities, and inadequate cooling systems combined. If coolant gets seriously low, cooling capacity is compromised and the engine overheats, either in challenging circumstances or sometimes in all circumstances.

When researching low coolant it's important to discover where the coolant is going. It's either leaving through the radiator cap or reservoir, or it's not. In either case, there are various mechanisms:

Coolant leaving SOMEWHERE BESIDES through reservoir or radiator cap

External leak
Internal leak

Coolant leaving through reservoir or radiator cap

A breached head gasket allowing combustion gas into the coolant, thus pushing the coolant out the reservoir.
A bad radiator cap allowing coolant out the reservoir (or occasionally right out the cap).
An existing overheat venting excessive coolant into the reservoir, overflowing the reservoir. Note the coolant could be in vapor form.

Flush and refill the radiator according to the manufacturer's specifications. This service should include replacing the pressure cap and adding anti-freeze if necessary. A quality repair shop has a tool that can check your car's antifreeze/coolant to make sure that it will provide adequate freeze protection.

Do you have a cracked water pump or just need auto repair?

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