Cooling System Maintenance Tips

A late model vehicle builds enough heat to warm a three bedroom home on a zero degree day!

A cooling system in poor condition can cause overheating during simple tasks such as sitting idle in traffic . If you do get caught in traffic and you notice the temperature gauge beginning to rise, the National Automotive Radiator Service Association (NARSA) offers up these cooling system maintenance tips to keep your vehicle from overheating:

  • Turn off the A/C-The extra heat from the A/C condenser in front keeps the radiator from removing engine heat.
  • Turn on the heater -The heater will draw some of the heat from the engine to the inside of the vehicle. Once you safely have pulled off of the road, turn off the vehicle to let the engine cool down.

Have a preventative cooling system check at least every two years. The test should include:

  1. Radiator pressure cap test to check for the recommended system pressure level
  2. Thermostat check for proper opening and closing
  3. Pressure test to identify any external leaks to the cooling system
  4. Visual inspection of all cooling system components, including belts and hoses
  5. System power flush and refill with car manufacturer’s recommended concentration of coolant
  6. Engine cooling fan test, for proper operation.

AC Repair

AC Vents

Let’s look at how the air conditioning (AC) system works.

The objective of the air conditioning system is to remove the heat from inside the cab of the vehicle. The compressor pumps refrigerant throughout the AC system. This refrigerant is a gas and liquid combination that is compressed and circulated under pressure and is passed through a special valve called an expansion valve that causes the refrigerant to expand.

This expansion makes the refrigerant very cold. This cold gas makes its way via metal lines into the dash area of your vehicle to the evaporator core. This evaporator core is like a small radiator, except it has cold refrigerant circulating inside and not hot antifreeze. A small fan (the AC blower fan which you control from the control panel on the dash) sits in front of the evaporator core and blows air across this cold evaporator and then through the vents inside your vehicle.

The compressor then sucks the warmed refrigerant into the condenser located at front of the vehicle. The condenser will have an electric cooling fan mounted in front or behind it to push or pull air through it to remove the heat from the refrigerant. Some vehicles still use the old fashioned fan blade driven by the engine to pull air across the radiator and the condenser.

A few causes of low air conditioner cooling or no cooling at all at idle are:

  • Lack of air flow across the condenser. Make sure the electric cooling fan motor near the condenser is coming on, or in models that are equipped with a fan blade make sure this fan is turning very fast.
  • Low refrigerant levels. refrigerant level and pressure should be checked by your certified air conditioning mechanic.
  • Overheating. If the engine is overheating, it can have a noticeable negative affect on the air conditioning system. Some cars have two electric cooling fans, one for the air conditioning condenser and the other for the radiator. Make sure they are both working properly. Usually at idle on a hot day with the AC on both fans will be on.

When the vehicle is traveling at freeway speeds, the compressor is pumping the refrigerant throughout the system much faster and harder than at idle. There is a dramatic increase in air flow across the condenser  and the engine is usually operating at a cooler, more efficient temperature as well, thus allowing the air conditioning system to operate efficiently. An air conditioning system that is somewhat low on refrigerant can still feel comfortable at freeway speeds due to the added air flow across the condenser which can overcome the ill effects of slightly low refrigerant. Periodic air conditioning performance checks by your mechanic are the best way to keep the system in great shape.

Cooling System Flushing – We Do It!

Flushing Boy

Well…not really this kind of flushing, but the concept is the same!

We start by attaching the hoses from the coolant flushing machine to several places in the cooling system and then use the pressure from the machine to shove out the old coolant and crud suspended in it. The flush process takes about 3 hours, including time to allow the hot engine to cool first. A cooling system flush, though, will not usually cure an immediate overheating problem due to plugging.

Most radiators today are small, made of lightweight aluminum, and crammed so tightly in the front of the car you can barely see it. The inside of the radiator is made up of a honey comb maze of tubes that sends the hot antifreeze on a long meandering journey inside the radiator.

The majority of the rust, dirt and sediment will be trapped at the bottom of the radiator, and we will not be able to remove enough of this compacted material to make any real significant difference in cooling ability of the system. A flush will, however, remove suspended sludge before it can settle and become compacted. Calcium and rust build up within the tubes are the main causes of radiator stoppages, and will likely cause over-heating. Also, the additives in the antifreeze deplete and break down with time and mileage and should be replaced with fresh coolant.

At some shops the term “flushing” the cooling system has been replaced with “draining and refilling” the cooling system. Removing the lower radiator hose or radiator drain cock to drain out the old antifreeze and replace with the new fluid is essentially “draining and refilling the cooling system.” This of course will only remove old contaminated fluid, along with any minor surface debris. If the radiator IS stopped up, removal of the radiator from the car for rodding-out and rebuilding, or replacing the radiator are really the only two viable options.

There are many “radiator flush” additives on the market, There are very few cooling system problems that can be solved by the contents of a can.
Flushing your auto radiator and installing new coolant every two to three years WILL help maintain and extend the life of your vehicle, but will probably NOT cure a major over-heating problem.

Plastic Radiator Repair

Radiator TanksYes! We can repair many plastic tank radiators. When a plastic radiator tank cracks it cannot be repaired, but many times it can be replaced, depending on the condition of the radiator.

Causes Of Engine Overheating

overheated engine

One of nature’s basic laws says that heat always flows from an area of higher temperature to an area of lesser temperature, never the other way around. The only way to cool hot metal, then, is to keep it in constant contact with a cooler liquid, and the only way to do that is to keep the coolant in constant circulation. As soon as the circulation stops, temperatures begin to rise and the engine starts to overheat.

Engine overheating can be caused by a combination of two factors: too much heat or not enough cooling.

Not enough cooling may be due to:

  • Low coolant level due to a coolant leak (internal or external)
  • Poor heat conductivity inside the radiator because of accumulated deposits. The most common problems radiators fall prey to are clogging (both internal and external) and leaks. Dirt, bugs and debris can block airflow through the outside of the core and reduce the radiator’s ability to dissipate heat. If clogged internally, the radiator must be removed for cleaning. Backflushing the cooling system and/or using chemical cleaners can remove the old antifreeze and some rust and scale, but will do little to open up a clogged radiator.
  • A defective thermostat that doesn’t open
  • An inoperative electric cooling fan or fan clutch. With an electric cooling fan, check to see that the fan cycles on when the engine gets hot or when the air conditioner is on. If the fan fails to come on, the problem may be with the fan motor, fan motor relay, or temperature sensor
  • A collapsed radiator hose
  • An eroded or loose water pump impeller
  • A defective radiator cap.
  • Excessive heat buildup due to a defective engine.
  • Excessive heat buildup due to conditions not connected to the cooling system, such as: front end out of alignment, restricted exhaust system, defective transmission.

Your engine may not be overheating at all. Your temperature gauge or warning lamp may be coming on because of a faulty coolant temperature sensor. Sometimes this can be caused by a low coolant level or air trapped under the sensor. If the cooling system has a bleeder valve, you have to temporarily loosen it to get all the air out of the system. Air pockets in the head(s), heater core and below the thermostat can also interfere with proper coolant circulation.

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