AC System and Coolant

Auto Mechanic Albuquerque:

How to Maintain and Inspect your AC System During the Summer Months

It is important to get your air conditioner checked for leaks and recharged to ensure optimal performance during the Hot Summer Months.  One thing that No One wants to happen is for your Air Conditioner to Stop Working, especially, on a very Hot Summer Day.  With step-by-step instructions, you can Do-it-Yourself.  If it seems too hard to tackle, then you may want to take your vehicle in to a Reliable Repair Shop.  This page will give you the knowledge of what the repair shop needs to inspect.  If you could pin point the problem yourself, you could save yourself money when visiting the repair shop.  This page will also tell you how to check and maintain you Antifreeze and Coolant Levels for your radiator.

Your Personal Mechanic should be able to check this out for you at little to no cost.   Service may be required after inspection.

Warning:  Be very cautious when inspecting and repairing your vehicle Air Conditioner yourself.  You should wear eye protection and take great precautionary measures.  Air Conditioner systems contain high pressure gas that when released can cause personal injury.  Use all safety precautions.  The Refrigerant for Air Conditioners is very harmful and can cause damage to your skin and eyes.  This Refrigerant is Freon.  Read all directions and follow instructions very carefully.  This is for your safety.

If you are having problems with your air conditioner and it is blowing hot air there are several things that you need to inspect.  A basic Air Conditioner Gauge and Test light is needed to help diagnose most air conditioner problems.

This is an illustration of how your Automobile Air Conditioning System Works


Check Drive Belts.

The Drive Belt is what the Air Conditioner uses to supply the power to rotate the compressor (a refrigerant pump).   If the belt fails the compressor has nothing to drive it.   Inspect and replace the Drive Belt as needed to restore the operation of your air conditioner.  If the Drive Belt is intact, then proceed to the next step.

Drive Belt


Check the Compressor Clutch.

To check the Compressor Clutch, your will need to turn the air conditioner on.  Set the air conditioner to the coldest position.

Start your vehicle and let it just idle.

Find the compressor that is under your hood.  The clutch is at the front of the compressor.  Make sure that it is turning.  If it is turning then you have enough refrigerant.  If it is not turning, then you could be low on refrigerant.  It could result in the Compressor to cycle “on and off”.  It will also be making a ticking noise.

If the Compressor Clutch is not turning, you will need to check for Refrigerant Leaks.  Another problem may be a blown fuse or a wiring problem.

If you are going to try to tackle this repair by yourself, you will need to purchase an “Air Conditioner Recharge Kit”.

Compressor Clutch



Inspect hoses for leaks.

The most common cause of an automotive Air Conditioner not working properly is from “little to no Refrigerant”.  Therefore, there must be a leak somewhere.  These leaks will need to be identified and repaired before the Air Conditioner can be recharged.

Leaks can be easy to find.  The leaks leave behind a residue from being wet around the leak.  This residue will be sticky with Freon oil and dust.



The most common cause of a Refrigerant Leak is due to an O-Ring.  Check the O-Rings first.  O-Rings are very inexpensive to replace.  Sometimes they just need to be tightened.

An O-Ring is located at every connection from the different components to the hoses.  The O-Rings can become loose during vehicle operation.  Check the O-Rings for loose connections.  If they are loose then, just tighten.Check for wear and tear of the O-Rings and replace the O-Ring if necessary.  These O-Ring issues will cause the Refrigerant (Freon) to leak out.

A lot of parts stores are selling stop leak chemicals for Air Conditioning Systems.  I recommend Not using these products because, they cause problems with the refrigerant recovery machines.  A lot of repair shops will not service your Air Conditioning System if the use of stop leak is detected.  Using stop leak also causes the cost of servicing your Air Conditioning System to go up.



Inspect the cooling fan operation.

Electric cooling fans come on when the Air Conditioner is turned on.  If the fan is not working, the efficiency of your A/C system will be affected.  This may cause your A/C to not work at all.

The Electric Cooling Fan/Fans are normally located on the radiator.

Vehicles with out Electric Cooling Fans use a Thermal Activated Fan Clutch which pulls air through the condenser just like an Electric Cooling Fan.  The Fan Clutch should be inspected as well.

The Thermal Activated Fan Clutch is located on the Fan Blade Assembly.It is in between the radiator and the engine.

Cooling Fan and Cooling System


Check the radiator and condenser for obstructions and debris.

Any debris that prevents air flowing through the condenser and radiator will cause the Air Conditioning System to perform poorly.

A garden hose with low water pressure will often clear the debris.  The vehicle must be turned off at this time.

Radiator and Condenser


Check operating pressures of the system.

This must be done by a professional.  The professional should have all gauges and training required.  The system operates under High Pressure and should only be serviced by a professional.  Attempting to add refrigerant to your own A/C System is not recommended.

Remember:  Just because your A/C is not blowing cold air, does not always mean that it is low on refrigerant.

Check the outlet temperature of the vents from inside the vehicle.

You should feel cool air coming out of the vents.  The temperature depends on ambient temperature and humidity.  If the temperature does not seem cool enough have the A/C System inspected.

Check operation of the control unit of the Blend Door.

The Blend Door is usually located under the dash on the evaporator unit.  Its purpose is to close off Hot Air and close off Cold Air or blend the two together.  Some vehicles have problems with the Blend Doors or the devices that operate them.

With the vehicle on and at operating temperature, move the temperature control to hot.  You should feel a significant change in the heat coming out of the vent.

Then turn the vehicle temperature to cold with the A/C on and the temperature should change to cold.  If this does not work well for you, then take it to a professional for inspection.

Look for other things that can go wrong:  bad switches, bad fuses, broken wires, broken fan belt (preventing the pump from turning), or seal failure inside the compressor.

These are things also to be performed by a professional.

WARNING!   Before any air conditioner repair work can be performed, the system must be evacuated of all refrigerant.  If you do not evacuate the entire refrigerant, personal injury can occur.  It is under High Pressure!

Servicing The Air Conditioning System should be performed by a professional.  The gases used should not be leaked in to the atmosphere.  Specialized equipment is used by the professionals to capture the refrigerant.

As you can see, the Air Conditioning System can be very complicated and cost a lot of money for repairs.

With step-by-step instructions, you can Do-it-Yourself

or at least most of the job.

Do-it-Yourself Repair and Maintenance Manual

Check and Maintain Your Antifreeze and Coolant Levels for the Summer

A common cause for automobile breakdowns is due to a Coolant System Failure. If you plan on servicing your coolant yourself there are some things that you need to check first.

Check the label on the coolant bottle. It has to be the correct type of coolant for your type of vehicle. Read the radiator section of your vehicles Owners Manual.

Use 50/50 percent of antifreeze and water.

If you no longer have your vehicles Owners Manual…You can find the information for your vehicle here:

Information For Your Type of Vehicle




Coolant or Antifreeze Performs Two Critical Functions:

1. It keeps the radiator fluid from freezing in the winter.

2. It keeps the engine from overheating in the summer.

Coolant is composed of 50 percent ethylene glycol and 50 percent water, which helps raise its boiling point and lower its freezing point. Corrosion inhibitors protect vital metallic cooling system components from corroding, and silicates lubricate seals.

If you have to add coolant there may be a leak. Have your vehicle inspected for coolant leaks. An over heated engine is the one of the Worst Problems for your vehicle. It would save you more money to have it inspected rather then risk it over heating. Your Personal Mechanic should be able to check this out for you at little to no cost. Service may be required after inspection.

The Radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating.

Radiator or Coolant Reservoir holds the coolant overflow from the radiator. This is also where you should fill the cooling system. It’s normally a white tank mounted under the hood on the passenger’s side. If the radiator fluid does become low then, it will begin to siphon from the reservoir and back into the radiator. So it is important to keep the reservoir fluid checked too.

Do-It-Yourself Radiator Coolant Check and Maintenance

First things first: Warning! You must make sure that your engine is Cool. Your engine is Hot and so are the fluids with in. That heat also causes pressure. You can get badly burned. Let your car sit for a while.

Check to see how warm it is before you begin anything.

Put your hand on the upper radiator hose to make sure that it is not to hot. It should be cool.

Squeeze the hose or hold it to see if there is any pressure in it what so ever. If there is pressure in it then, coolant will spill everywhere and even on you. Blistery type of burns. The radiator hose should be cool.

You can also touch the Radiator Cap. You can feel pressure or heat. It should be cool. There is a Warning Label on your radiator cap as well.

After you know that everything is Cool…Twist the Radiator Cap and remove it. You can use gloves or a paper towel to help remove the cap. Press down and start to twist (lefty loosy). Listen and feel for pressure.

You will then look at the fluid level. The fluid should be right at the top. If the fluid is at the top then your fluid is fine. You can just put your cap back on, push down and twist (righty tighty). Pay attention to the notches and the tabs that are on the cap, and line them up with the corresponding notches and tabs that are on the top of the radiator. Make sure that the cap is locked in place. That is very important because, when the fluid gets hot it will build pressure, pop off the radiator top, and you will have a MESS.

Another Safety Precaution: If you do spill any antifreeze on the ground or anywhere, make sure and clean it up well. It is very Harmful and Deadly to pets. Animals will try and drink it. It tastes real yummy and sweet to them. Don’t let this happen or you just might be a cryin.

Here is a picture of where the Radiator Cap is on your car.


If your fluid level is low and not right at the top, then just use the correct fluid and top it off.

  • Remember, your fluid should be 50/50 percent of antifreeze and water.
  • Some of the antifreeze on the market will already be 50/50 per-diluted and Ready for Use. With this type of antifreeze you can just poor it right in to the radiator or the radiator reservoir.
  • There is also coolant that is Not diluted. You will have to mix this your self and use the correct ratios of water to coolant. The instructions will be on the back. Use distilled water as tap water can build up mineral deposits in your cooling system.
  • Tip: If you have to mix your one coolant to water ratio, mix it in a separate container outside and away from the vehicle. Once you get your proper mixture, and then add it to your radiator or radiator reservoir.

To Fill the Radiator Reservoir:

  • Unscrew the cap that is on top of the white tank.
  • Pour the fluid inside until you see the fluid level rise between the minimum and maximum lines on the side of the reservoir.

This is a picture of the Radiator Reservoir. It is located under the hood on the passenger’s side.


Check your Radiator Hoses: There are 2 hoses to check.One connects at the top of the radiator and one is at the bottom.

  • Visually inspect your hoses.
  • Check the clamps that clam from the radiator to the engine are secure and that there are No leaks.
  • Make sure that the hose itself is Not Cracked.
  • If your radiator hoses are cracked or there is any leaking: The hose or clamps will need to be replaced.

Here is a picture of the Upper Radiator Hose and the Radiator lid.



Here is a picture of the Lower Radiator Hose:Remember, each vehicle is slightly different.



There is a way for you to Do-it-Yourself. You can repair or at least maintain your vehicle yourself and save yourself a lot of money. You can find the right Do-it-Yourself Repair and Maintenance Manual for your particular vehicle by clicking the link below.

Do-it-Yourself Repair and Maintenance Manual

Thank you once again for visiting my site. If I can be of any service to you, please contact me by email or by leaving a comment on my blog. We can communicate by phone if needed.

I am honored to serve you and all of your Automotive Needs.

Ken Snoeberger


XpectMore Automotive

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