Cooling
Systems
The U.S. Department of Transportation says cooling system failure
is the leading cause of mechanical breakdowns on the highway...thus,
what follows is definitely worth a few minutes of your time.
One Third – Two Thirds
As your engine consumes fuel, only about a third of the released
energy goes into mechanical energy to run your car. The rest,
fully two-thirds, is converted to heat. Some of that heat finds
its way out of your car via your exhaust pipe, while the rest
heats the engine itself (ever stick your face in the engine compartment
on a hot day?). Your car’s cooling system is designed to
accomplish one simple objective…remove excess heat from
your engine.
Without a cooling system, the engine would be destroyed by heat
within a half hour of startup.
The cooling system works by moving coolant (which is stored in
the radiator) through the engine and then back through the radiator
where its heat is transferred to the surrounding air thanks in
part to the fan blowing through the radiator and in part to the
forward motion of the car which drives air through the radiator.
Some cars have electric fans (usually front wheel drive cars) while
some are driven off the car’s engine (usually rear-wheel
drive cars).
Thermostat
Coolant flow is regulated by a thermostatic valve or thermostat.
This little device works to allow the engine to heat up quickly,
and then keep the engine at a constant temperature. This is accomplished
by regulating the amount of water that goes through the radiator.
At low temperatures, the thermostat’s outlet to the radiator
is completely blocked. In other words all of the coolant is re-circulated
back through the engine.
Once the temperature of the coolant rises to between 180 and 195
F (82 - 91 C), the thermostat starts to open, allowing fluid to
flow through the radiator. By the time the coolant reaches 200
to 218 F (93 - 103 C), the thermostat is open all the way.
Things to Watch Out For
Several conditions can arise in your cooling system which would
put your car under a black cloud or at the business end of a
tow truck:
Leaky radiators and hoses – this causes coolant to leak
out and the engine to overheat. Overheated engines have a tendency
to seize, freeze, warp and, in general, lock up. If this happens,
may we suggest you find a place to sit down before you look at
the repair bill?
Broken fan belts can essentially stop your engine cooling system
in its tracks thus causing overheating as they prevent the water
pump from circulating coolant and the fan from cooling the coolant.
Ethylene glycol, the main ingredient in most antifreeze, never
wears out. What does wear out are the corrosion-inhibiting additives
that protect the cooling system. Nor does the coolant remain
clean forever. It picks up contaminants and byproducts of corrosion.
The only way to get rid of the contaminants is to replace the
coolant or filter and treat it on a regular basis.
Your cooling system relies on a water pump to circulate your engine’s
antifreeze. It turns whenever your engine is running, so after
a while, the bearing surfaces and seals get worn. When that happens,
the pump can't turn freely, or it begins to leak coolant. That's
when it's time to replace the water pump.
Coolant Expansion Tanks
The coolant expansion tank is connected to the cooling system (radiator)
through a system of hoses. It provides for escape of pressurized
gases and absorbs the coolant’s thermal expansion during
rapid pressure buildup. It also prevents the coolant from boiling
over when the hot engine is shut off.
How Not to Lose Your Cool
There are several steps you can do to help assure your cooling
system operates properly. Pop your hood and look at the expansion
tank every few weeks. Most have clearly visible lines showing
where the coolant level should be – whether is the engine
is hot or cold. Be prepared to add coolant if necessary.
Keep an eye on your dashboard temperature gauge. Regardless of
whether its July or January, your gauge can be the first sign of
trouble in a malfunctioing cooling system. And yes, cooling system
failures can happen when the snow flies just as easily as when
the sun shines.
Keep a record of when you last changed your anti-freeze. At Dallas
Auto Sports, we recommend changing your coolant every 24,000 thousand
miles or two years. This seems like a good place to remind you
to also keep records of when you change oil and rotate your tires.
Dallas Auto Sports
As you’ve probably seen by now, your cooling system’s
health is very important to the health (and longevity) of your
car - especially in the middle of a hot Texas summer.
As you’ve probably also seen by now, it takes a fair amount
of experience to diagnose and repair a modern car’s cooling
system. We might add, a key part of this process is the anticipation
factor.
We look at fan belts (which drive water pumps and cooling fan)
and radiator hoses and the coolant itself and based on our experience,
will counsel you on whether your car needs preventive maintenance
or whether your system is in fine shape.
If you have concerns about the state of your cooling system, give
us a call, stop by, or email us.
Dallas Auto Sports
8912 Garland Road
Dallas, Texas 75218
Mon. - Fri. 8 AM-5 PM
214.320.2228
service@dallasautosports.com
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