If your car overheats
and damages the engine, you have no one to blame but yourself. Keep your eyes
on the temperature gauge and never let the needle move into the red. Pull over
before it gets too hot.
Tips & Warnings
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:
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.
Diagram of a cooling system: how the plumbing is connected
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
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
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.
Skyway Auto Tune of Paradise CA. Voted
Best On The Ridge Offers Full Service Auto Repair and Smog for Domestic
and Import Vehicles.
We are the Best of Northern
California’s Auto Repair and Smog Check Stations.
Automotive Cooling SystemService -
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!
How Your Automotive Cooling System Works
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
By forcing excessive coolant out the reservoir, thereby creating a low-coolant
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
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
Corrosion can occur when additives that protect the cooling system
have been depleted.
Scale and Sludge can plug
cooling system fins, preventing proper circulation of coolant.
Do You Have Low Coolant Levels?
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
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.
Here's A Tip to Keep Your Radiator
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