Automotive cooling systems and the materials used in them have changed remarkably over the years. Gone are the days when car radiators were constructed of steel and brass and you repair them with solder or a brazing rod. Most of today’s radiators are constructed of plastic and aluminum; the top and bottom tanks are plastic and they are chemically bonded to an aluminum core. These new plastic and aluminum radiators are much more easily damage and are much more difficult to repair. Also, today’s radiators are much more difficult to remove and replace because of how compacted the engine bays are in today’s compact cars, so we need to do everything in our power to keep these radiators trouble free.
The coolant circulating in your cars cooling system serve many functions besides transferring heat from the engine to the environment. As a rule the coolant consists of a 50-50 solution of glycol and water. Ethylene glycol is a heat transfer fluid serves two basic functions in our coolant; it raises the boiling point of the solution to 225°F which is 13°F higher than water and it protects the coolant against freezing down to -36°F, which is more than adequate protection for most areas of the United States. The ethylene glycol components act to stabilize engine temperature under all operating conditions.
Until recently, ethylene glycol was the only glycol based coolant available but ethylene glycol was a very toxic substance, poisonous to both people and pets. It caused birth defects, reproductive damage and even death. The fact that ethylene glycol has a sweet odor and taste makes it very dangerous to animals because they have no awareness of what it actually is. Today there is an alternative, propylene glycol which is significantly less toxic. It’s still not safe to ingest but it’s significantly less deadly in small amounts and that’s why you will need a catch pan when you drain the coolant from your cooling system.
Automotive coolants also contain other additives that prevent corrosion from taking place inside the engine’s water jacket and keep metal particles circulating instead of forming obstructions in the water jacket and radiator. After a while the glycol and other additives lose their effectiveness and their ability to protect our car’s engine and cooling system and that’s why we need to drain and flush out our cooling system on a regular basis. Depending on the operating conditions, you should drain and flush out your cooling system at least once a year. Performing a cooling system flush as part of winterizing you car is a good schedule to follow.
The proper way to drain a car’s cooling system varies slightly for different make and model vehicles. Some vehicles have drain cocks on both their radiators and lower engine blocks, while with others you have to remove one of the radiator hoses to drain the engine block. Because of this the instructions that I will give in this article will be generic and not for any one specific vehicle. Specific information may be available in the maintenance manual that came with your vehicle but you should still purchase a repair manual for your vehicle. A good choice is one by Hayes or Chilton one or both of them are carried by most auto parts stores. A good service manual is the most valuable tool in any mechanic’s tool box.
The tools that you will need to perform cooling system maintenance.
· 3/8” drive ratchet set with SAE and Metric sockets
· Set of standard straight blade screwdrivers
· Set of Philips head screwdrivers
· Slip joint pliers
· 3/8” drive torque wrench
· 2” metal scraper or putty knife
· Drain pan
· Jack
· Set of jack stands
· Fender cover
· Garden hose
· Service manual for your vehicle
All of these tools are available at any automotive retail parts outlet like Auto Zone, Advance Auto Parts, or Pep Boys, but a good source for quality tools at an exceptionally reasonable price is Harbor Freight.
The supplies that you will need
· Thermostat w/housing gasket
· Permatex #2
· 50/50 coolant solution
· Upper radiator hose (if needed)
· Lower radiator hose (if needed)
· Heater hoses (if needed)
· Bypass hose (if needed)
Let’s get to work
· Jack the car up and support it with jack stands. Never work under a car that is supported solely by a jack. Jacks can and often do slip, resulting in serious, often fatal accidents.
· Place drain pans under the radiator and engine block.
· Open the radiator’s drain cock and remove the drain plug from the lower engine block or remove the lower radiator hose if that’s the way your engine block is drained. Check your service manual for the location of drains.
· This is a good time to check all the hoses for damage and replace any that have cracks, feel spongy, or appear to be heat damaged. Don’t forget the heater hoses and the bypass hose.
· Remove the old thermostat and temporarily replace the housing. Check your manual for directions on how to do this if you need to.
· Replace any of the hoses that need replacing and any hose clamps that are corroded at this time.
· Place the garden hose in the radiator and run water through the system until the water draining from the radiator appears clear and clean
· Remove the hose to the overflow tank and flush the tank and hose by placing the garden hose in the overflow tank.
· Replace all the hoses and close all drain cocks and replace all drain plugs.
· Remove the thermostat housing; scrape the mating surfaces until they are free of all the old gasket material. Coat the mating surfaces with Permatex and then install the new thermostat using the new gasket.
· Fill the radiator with the 50/50 solution, leaving the radiator cap off.
· Start the engine and wait for the thermostat to open.
· Once the thermostat opens, the coolant level will drop as the engine block starts to refill.
· Top off the coolant and replace the radiator cap.
· Let the engine run for a few minutes and then check for leaks.
· Jack the vehicle up and remove the jack stands.
· Remove the jack and you have successfully serviced your vehicles cooling system.
· Pour the old coolant into the newly emptied coolant containers to be transported for recycling. Most auto parts stores will accept and recycle automotive fluids for free.
