A/C & Heat

 
 

  • REPLACING THE WATER PUMP

You will need:

1. Open or box end wrenches
2. Ratchet wrench set with universal joint
3. Assorted screwdrivers
4. Drain pan
5. Gasket scraper
6. Wire brush
7. Water pump and gasket
8. Permatex #2 gasket sealer
9. New hose clamps

REMOVAL

Drain the coolant from the radiator or engine block into a clean drain pan. Some vehicles require that you remove one end of the lower radiator hose to drain the system. If the coolant is rusty, dirty or over two years old, dispose of it properly, and flush the system before replacing the pump, as contaminated coolant could cause failure of the new pump.

To remove the fan and fan clutch, start with the fan shroud (if you have one) and move it inward over the fan. Remove the fan bolts, and take the fan and shroud off together. If the vehicle has a fan clutch, you might want to consider replacing it at this time. Fan clutches should always be laid face down to prevent damage and assure proper operation. Check the fan for cracks, bent blades or other defects. Don't try to repair a damaged fan, always replace it.

Remove other components as needed to make the water pump accessible. These would include the belts, alternator, power steering pump, and air conditioning compressor. It is not always necessary to remove the hoses or wiring to these components most times you can just move them out of the way - simply place them out of the way. Remove all heater and by-pass hoses that are connected to the water pump. At this time, remove any hose fittings that thread into the pump.

Remove the water pump attaching bolts, noting their lengths and positions for correct replacement. Remove the pump from the engine.

IMPORTANT: If the pump does not come off easily, check to be sure all the mounting bolts have been removed. Do not try to force it off. After the old pump has been removed, carefully clean all the old gasket material from the mounting surface of the engine. Also wire brush the threads of the water pump mounting bolts to pre-pare for reinstallation.

If required, transfer the studs for fan attachment from the old pump to the new pump. This is most easily accomplished by using the "double nut" method.

INSTALLATION

When mounting the new pump, be sure the new gasket matches the surfaces to be sealed. Lightly coat both sides of the gasket with gasket sealer and position it on the engine. Also, lightly coat the threads of any bolts threading into a coolant passage with a non-hardening sealer. Install the new pump and attaching bolts (hand tight) in their original positions. Give the pump shaft a quick spin to check for free operation. Tighten the pump mounting bolts, using care not to over tighten, as possible pump damage may result.

Reconnect all hoses replacing those that feel brittle, mushy or are cracked. Be especially critical of bypass hoses, or others that may be difficult to replace after assembly is complete. Use new clamps and apply sealant on any corroded hose connections.

Remount other components that were removed earlier, referring cars repair manual if needed. Reinstall the belts for each component as you go, using new ones if the old ones are cracked, glazed or frayed. To tighten the belts, put tension on them by using a soft piece of wood as a lever, prying the component outward until the belt is tight. In most cases, applying hand pressure is the best method for tightening. Whatever method you choose, be careful to avoid damage to other engine components.

Check all of the hose connections for tightness, then close the radiator drain, and add your coolant in the proper mixture.

Reconnect the negative battery cable. Start the engine and check for leaks and the proper operation of all components disturbed during the process. The heater valve must be open, (heat on, temp on hot) to assure complete circulation of coolant. Run the engine without radiator cap until it reaches normal operating temperature to purge the system of air. Top off the radiator and reinstall the radiator cap. Any further coolant level checks should be done at the coolant reservoir only.

Look over the entire system for leaks after it has reached operating temperature, with the radiator cap installed.

After the engine has run for at least 15 minutes, turn it off and recheck the belt tension. Retighten as necessary.

Check the antifreeze protection level. A 50/50 mixture will give the best protection against winter freezing and summer boil over.

Check the operation of the heater. If it doesn't function correctly, allow the engine to cool and recheck the coolant level.

Road test the vehicle to make sure the coolant remains in the specified limits. Also check the operation of the other components that may have been removed or loosened during this procedure involved (power steering, air conditioning, etc.)

Bleed the air from the cooling system if required for your vehicle.

You will Need:

1. Flat head screwdriver or nut drivers
2. Ratchet and socket
3. Drip pan
4. A rag
5. Flat scraper to remove the old gasket.

Although water pump failure is often the cause of overheating, it never hurts to take a quick look at what could prove to be a simple quick fix. As often as the water pump goes bad, so does that pesky thermostat.

Because the thermostat is cheap and replacing it is simple it isn't a bad idea to try this repair before getting into more difficult manuevers.

REMOVAL

Although some thermostats are located where the bottom radiator hose joins the engine, the vast majority are on the top hose. Locate the hose and unscrew the clamp that attaches it to the engine.

When the clamp is loose, pull the hose from the engine. You may lose a bit of fluid here so make sure you have a drip pan in place under the vehicle.

When the hose is removed you will need to remove the bolts that hold the thermostat housing in place. Once you have removed the housing, simply lift out the old thermostat.

CLEANUP AND INSTALLATION

In all likelyhood, some of the gasket that rested between the housing and the engine will remain stuck. Remove the old gasket by plugging the hole with a rag and scraping away the gasket. This will insure that none of the old gasket accidentally falls into the cooling system.

After you have cleaned up the area, you are ready to install your new thermostat. You should always use the recommended unit because thermostats that open at the wrong temperature can cause several problems resulting in sludged oil and damaged components.

Set the gasket in place and remember to install the thermostat with the power unit pointed towards the engine block. After it is in place, replace the bolts and snug it down.

After you have tightened it down, replace the hose and clamp you removed earlier. If you lost any fluid during the job, you need to refill the system. Although you can reuse the fluid you caught in your drip pan, I'd recommend filling with fresh fluid to avoid worrying about what else may have mixed with the fluid in the pan.

You will need:

1. Nutdriver
2. Pliers
3. radiator fluid pan or bucket
4. Replacement hoses and new clamps

Optional items: White grease, fresh radiator fluid, small rubber hose, carter key removal tool

Notes : If you're replacing a radiator hose, its not a bad idea to replace them all. This repair is relatively inexpensive and changing all your hoses at once helps to insure even wear and eliminates the chance that you'll forget about an aging lower hose down the road.

Also, do yourself a favor and use new clamps as these wear too and corrosion, and loss of "spring" can cause older clamps to allow a leak, and a potentially more problematic issue can result.

Precautions: When changing your hoses make sure the engine is completely "cool." As an additional precaution, you may also wish to disconnect the negative battery terminal cable.

To begin, you will drain the current coolant from the radiator. Make sure your bucket or pan is in place, and release the petcock at the base of the radiator with a pair of pliers. (You may wish to use a small piece of hose on the drain hole to direct the fluid to your bucket, but this isn't absolutely necessary.)

Once the fluid has drained completely, tighten the petcock.

To remove the hoses, use your nutdriver to loosen the hose clamps that hold them in place. Once loose, move the clamps out of the way and slide them to the middle of the hose. Again, make sure your pan is in place to catch any fluid that may remain in the hose, and gently tug at the hose to remove it.

If your hose is "stuck" or will not release easily, you may wish to use the carter key removal tool to pry it free. Continue this procedure with each hose you will replace.

When placing your new hoses on the radiator, you may wish to use a small amount of white grease or a bit of radiator fluid to lubricate the inside of the hose and make it easier to slip back into place. This will make the hose easy to move as you line up the opposite end where it needs to attach.

When tightening your new clamps, make sure you hold the hose firmly in place, but do not tighten too far. You can actually damage the hose or cause a small leak if you overtighten the clamps to the point they tear or puncture the hose.

Once your hoses are back in place, refill your system with coolant, you may use the old coolant (provided your bucket or pan did not contaminate it with particles, oils, or other debris), but with as little as anti-freeze costs, a minimal investment is worth it here.

Generally speaking, you will fill the system with a 50-50 mix of water and anti-freeze. Some areas that have particularly harsh weather conditions may change this ratio somewhat to favor a bit higher amount of antifreeze.

If you did disconnect the negative terminal, reconnect it. Take the car for a quick drive down the street or around the block and after take a quick look back under the hood to insure that you haven't inadvartently caused a new leak. If all is well, you're done.

You will need:

2. Basic Hand Tool Set
2. New Radiator
3. Jack & Jack Stands or Car Ramps

While there is no standard for the service life of a radiator, most quality radiators should last five years or more. Like everything else on a vehicle, this depends on the car or truck's operating conditions and maintenance record.

It is very important to flush your coolant at regular intervals of two to five years (depending on the type of coolant used). Additionally, you may want to flush your cooling system before replacing the radiator.

CHOOSING A NEW RADIATOR

Although any radiator listed for your vehicle should fit and function the same, there can be a number of differences between brands. The first and generally the most important feature to look for is a suitable warranty.

Quality radiators should come with warranties of at least five years. Secondly, check to ensure they are the same thickness (which is the number of cores) as your original radiator. The greater number of cores, the better the radiator will cool.

Keep in mind that fit may become a problem with heavy duty radiators.

Check the material used in the radiator's construction. The cooling surface (fins) should be aluminum and not be damaged. The tanks on the side may be plastic or other metal.

Keeping the price in mind, I usually suggest a new radiator. Remanufactured units may appear to be in good shape, but they may have weak spots in the metal or rust deposits.

REMOVAL

Start by disconnecting the battery and remove any plastic covering over the top of the radiator. Then open the drain valve and drain the radiator's antifreeze. You will find the drain valve at the bottom of one of the side tanks.

On vehicles equipped with electric fans, disconnect the fan wiring and remove the shroud as a unit. The shrouds are usually attached with four bolts (one at each corner). On vehicles with engine driven fans, unbolt and remove the fan blade assembly, then remove the fan shroud. On some vehicles, the shroud can be removed in two pieces and on others, you may be able to remove the radiator without actually removing the shroud or fan (you will still need to unbolt the shroud).

Disconnect the upper and lower radiators hoses and any transmission cooler lines. Transmission cooler lines can often be difficult to remove and there are special "Line Wrenches" designed for this purpose. Using a standard wrench can cause the steel line to twist and kink.

Note: On some Ford vehicles (including the late-model Ford Taurus and Mercury Sable), you can not remove the radiator from above. The job involves removing the front bumper cover, lower cowling, and more, and is therefore beyond the scope of this article.

MIXING ANTIFREEZE

The general rule of thumb for mixing antifreeze with water is 50/50. This applies to most climates and virtually every type of concentrated antifreeze. In very cold climates, a higher ratio may be desired. Using any water suitable for drinking is acceptable; however, distilled water a better choice.

Distilled water does not contain any minerals, which can leave deposits in the cooling system.

Lastly, antifreeze and water do not need to be mixed in separate containers before adding to the system, nor should they. Since you've used water to flush the cooling system, there will be a considerable amount of water remaining when you begin. This means you will need to add a higher proportion of antifreeze to reach the desired coolant mixture.

There is no effective scientific method of doing this, except to check the mixture with an antifreeze tester after it has been given time to blend, and adjust accordingly.

REINSTALLING THE RADIATOR

Installation is quite simply the reverse of removal and refilling the antifreeze. After you have the new radiator in place and all hoses, lines, fans, shrouds, and mounts in place, add the required mixture of coolant.

Fill the radiator and reservoir and start the engine. As the engine runs, coolant will begin to circulate and the level will fluctuate. Continue adding coolant to keep the radiator near full until the engine reaches operating temperature. Rather than fill it right to the top, leave a little space in the filler neck. Air, trapped inside the system, will work its way out and can splash the now-hot coolant out.

Turn the car's interior heater on. Shortly after the engine reaches operating temperature, the thermostat will open. When this happens, you'll notice a sudden drop in the level of coolant in the radiator as the system takes new coolant in. This may happen a number of times, until the system is completely full and free of air pockets.

It is sometimes difficult to remove all the air trapped in a system; it simply takes time. Take care, as the engine will now be very hot and can cause serious burns.

  • A/C RETROFIT

Safety Alert: Always disconnect the vehicle's negative battery cable before you begin engine or electrical-system repair work.

With the faulty seal on the compressor, not only has the refrigerant leaked out, but air and moisture has been allowed to infiltrate the system.

The accumulator is a part of the a/c system that helps to remove and dissipate moisture from the system. The accumulator has a metal exterior and contains chemical desiccant that removes moisture. With the system exposed, the desiccant becomes saturated, the containing bags can rupture, and the desiccant material contaminates the system. The accumulator will be replaced as part of this repair.

The orifice tube, located in the liquid line, regulates the flow of refrigerant gas through the system. Whenever replacing a compressor, the orifice tube should be replaced also.

The first step for accessing the a/c work-area is to remove the air-filter housing.

In order to work on the compressor, the a/c system must already be discharged of any remaining refrigerant.

Important: The use of R-12 refrigerant is regulated by the EPA. Never work on an a/c system that still contains it. Releasing R-12 is harmful to the environment. Have a certified a/c-repair shop remove and capture the refrigerant.

The drive belt must be removed before the compressor can be removed from the vehicle.

Inspect the drive belt once it is removed. If the belt is cracked and worn, too should be replaced as part of the repair.

With the belt removed, disconnect and remove the accumulator.

With the accumulator out, unbolt the compressor's retaining bolts, disconnect the electrical wires, unbolt any support brackets and carefully lift out the compressor.

Important: Always remove the compressor before flushing the a/c system. Flushing the compressor could cause debris to lodge in the oil channels, bearings or shaft seals.

After the compressor has been removed, take out the orifice tube. The tube contains a filter that will likely be contaminated with metal shavings and other debris. The orifice tube cannot be cleaned, so it will need to be replaced.

Important: The two ends of the orifice tube are not the same. When installing a new one, be sure to orient it properly.

System flush

The next step in the procedure is to flush the remainder of the a/c system, including the condenser unit and evaporator core. Flushing the system is important, since it removes any residue or contaminants that could damage the new compressor once it's installed. Also, since this repair involves upgrade from R-12 to R-134A refrigerant, the new system will use a different type of lubricant. It's important to remove any of the old lubricant that remains, since the two lubricants are not compatible.

To flush the system, use a funnel to pour flush solvent into the condenser and the evaporator. Make sure that the flush solvent that you're using is compatible with the a/c system your vehicle has. A/C flush-kits are available at auto supply stores.

Once the solvent has been introduced, an air compressor is used to evacuate the solvent and contaminants from the system. The air compressor is equipped with a fitting that allows the pressure-hose to be connected to the condenser line. If you don't have an air compressor, you can achieve the same results with two to three cans of compressed air.

The flushing procedure removes a substantial amount of contaminant particles, including the old mineral oil and loose desiccant material.

  • REPLACING THE COMPRESSOR AND RELATED PARTS

With the a/c system flushed, and worn-out parts removed, the next phase of the upgrade is to replace the compressor, accumulator, drive belt and other related parts.

The old, cracked compressor drive-belt will replaced with a new one.

Though the vehicle's air-filter is not directly related to the a/c system, since the filter and housing needs to be removed for the repair, it's a convenient time to go ahead and replace the old filter with a new one.

As discussed earlier, the old orifice tube - which is a metering device for the a/c system - is to be replaced with a new one, making certain it's installed in the proper orientation.

Replacing the drive-belt, air filter and orifice tube are all inexpensive preventive maintenance that should be performed during this repair and upgrade.

The major a/c components to be replaced are the accumulator, the clutch-cycling switch and, of course, the compressor itself.

The new (or remanufactured) compressor may come with an internal packing lubricant inside. This lubricant must be removed before the compressor is installed. Remove the drain plugs from the back of the compressor, and drain the lubricant into a drain tray. You may need to turn the clutch-hub a few times to force all of the packing-lubricant out.

Replace the packing oil with a compressor lubricant that is compatible with the upgrade refrigerant system. In our case, the appropriate lubricant is a PAG (polyalkylene glycol) oil. This is the best type of oil for R-134A systems.

Use a funnel to pour the appropriate amount of the new lubricant into the compressor. Check your service manual for the capacity of your compressor.

Rotate the clutch-hub a few times to make sure that the lubricant is introduced throughout the inside of the compressor.

With the oil installed, cap the oil ports with the plugs you removed earlier.

The last step in preparing the compressor for installation is to install the fan switch. Use pliers to remove the temporary plug in the new compressor.

Use the fan switch from the original compressor. The switch is held in place by a retainer ring.

With the fan switch installed, you can now begin reassembling the entire system prior to charging it with new refrigerant.

Install the new compressor, reversing the procedures you used to remove the old one.

Install the new drive belt.

Install the new orifice-tube and filter.

Tip: Lightly oil the O-ring on the orifice tube to help ensure a longer life for the part. Do the same for the O-ring for the line connection. Use PAG oil to lubricate the rings.

Remove the old low-pressure (clutch-cycling) switch.

Oil and replace the O-ring for the connector where the new switch attaches.

Install the new switch.

Reconnect the condenser lines, as well as all remaining electrical hookups.

Re-install the air-filter housing, install the new air-filter, and replace the cover.

The new accumulator is installed last, as it's best to keep it capped and the desiccant sealed from moisture until just before the part is installed.