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Four Symptoms Of A Sick Cooling System

Four Symptoms Of A Sick Cooling System

FOUR SYMPTOMS OF A SICK COOLING SYSTEM

Knowing the symptoms of a sick cooling system are critical to reduce your chance of an unwanted breakdown. The most noticeable symptoms of a sick cooling system are overheatingleaks, a sweet smell of antifreeze and repeatedly needing to add coolant.

“Neglecting your cooling system can result in serious damage and even complete engine failure, which would put a sudden end to your summer road trip,” said Rich White, executive director, Car Care Council. “If the cooling system doesn’t receive regular maintenance, it’s not a question of whether it will fail, but rather when it will fail. Performing regular checkups of belts, hoses, the water pump and fluids will ensure your car remains properly cooled and healthy for many miles down the road.”

The primary job of an engine’s cooling system is to remove the heat that is generated during the combustion process. A vehicle’s coolant temperature can be well over 200 degrees and that heat must go somewhere, otherwise engine components are going to fail. The key parts of the cooling system that remove heat from the engine and automatic transmission are the water pump, radiator and thermostat. The water pump circulates coolant through the engine. The coolant absorbs heat and returns it to the radiator where heat is dissipated. The thermostat regulates the coolant temperature to keep it consistent for efficient engine operation.

  1. Overheating: An engine will often overheat when coolant is no longer circulating through the engine. Loss of circulation may commonly be caused by a coolant leak or a failed water pump or thermostat. If you are experiencing an overheating problem, then remember to never check Coolant levels while engine is Hot. Once the engine has cooled, then you can remove the radiator cap to determine if the coolant level is low. If coolant is low, then first check for leaks in hoses. If a leak is difficult to find, then you may opt to have a service center pressurize the cooling system to locate a coolant leak. Continuing to drive an overheating engine can quickly cause complete engine failure. Should you choose to add coolant to a system, then please remember to properly determine the coolant type. Mixing different types of coolant can cause gelling and possibly clog the radiator.
  2. Leaks:  Motorists can do a visual inspection of hoses, belts, thermostat, freeze plugs, fan blades and the radiator (including the pressure cap) to help identify cooling system problems before they escalate. Radiator leaks, bulging hoses or frayed and cracked belts are clues that the cooling system needs maintenance. Leaks in the cooling system can happen anywhere so do a thorough inspection if you suspect a leak. These can be an easy fix.
  3. Smell: The smell of antifreeze when it is hot smells like sweet syrup. The smell is sweet but unmistakable. This could mean a major problem for your cooling system. Again, there could be a leak or you could just be burning through coolant. This could mean a problem with your head gasket. An easy way to verify a head gasket leak is if you have white exhaust. White exhaust means that you are burning engine coolant in the combustion chamber of the engine. If this is happening you should stop driving the vehicle as further use will damage the internal working of the engine.
  4. Low coolant level:  Any number of causes can reduce the coolant levels in your car;

Overflow Reservoir: Most overflow reservoirs come equipped with a small tube that allows the coolant to escape if the engine gets hot enough and the coolant expands past the full mark on the overflow reservoir. This can happen on hot days when you also run your air conditioner. Because of this, you need to check the reservoir level periodically to ensure coolant is between the minimum and maximum marks on the reservoir. Use the recommended mix of coolant and water for your vehicle.

Radiator Leaks: Small pinhole leaks in the radiator will cause coolant fluids level to drop. Pinhole leaks may not be noticeable during operation, as the fluid will leak when the car is running under load. But after operation, the radiator will give off a hot moist smell and show signs of leaking underneath. Pinhole leaks will grow if not fixed. Replace the radiator or have it repaired at a radiator repair shop.

Leaking or Blown Head Gasket: A leaking or blown head gasket will cause water to leak into the areas of the block where it was not designed to go. This will cause the coolant fluid levels to drop without any noticeable leaks under the coolant reservoir, hoses or radiator. Another way to check for a faulty head gasket is to check the oil dipstick. Look at the color of the oil at the end of the dipstick. If it’s milky in appearance, or water bubbles appear, this is a good indication of a blown head gasket.

Hoses and Connections: Check all connections where hoses connect to the radiator and the engine. Make note if you see any fluid around these areas. Bad hoses may not show leaks until the engine is on. Replace any hose clamps or bad hoses. Include radiator hose inspection during oil changes or tuneups to prevent problems with the cooling system in the future.

Radiator Cap: A malfunctioning radiator cap can be the cause of fluid leaks in the coolant system. Never take a radiator cap off after the car was just shut off, as the system is under pressure. Wait until the radiator is cool to the touch before removing the cap. Replaceable caps are available from auto part stores for a small price.

You should also check the cooling system for electrolysis. This occurs when an electrical component is not properly grounded and routes itself through the cooling system in search of one. Likely sources are electrical accessories that are bolted to the engine and components in the cooling system, such as the starter motor or engine block to the battery ground connection. The destructive effort of electrolysis may be in the form of recurring pinholes in the coolant tubes of the heater and radiator core or where mounting brackets are attached.

Additional signs of cooling system problems include the vehicle temperature gauge rising near the danger zone, coolant leaks, steam or hissing sounds under the hood or the district smell of an engine that’s running hot.

Proper Maintenance

A major factor that affects the replacement of cooling system parts is the frequency of regular maintenance, such as coolant changes. Motorists should consult their owner’s manual for specific recommendations about how often to change antifreeze and flush the coolant system. A coolant flush and fill is basic to cooling system maintenance as new antifreeze helps the engine run cooler and a flush removes dirt or sediment that could damage other cooling system parts such as the heater core.

The coolant level should be checked regularly at the reservoir and motorists are reminded to NEVER open a hot radiator cap. If the coolant is low, a 50/50 mix of approved antifreeze and distilled water should be added.

We recommend testing your coolant and brake at each oil change to closely monitor when the best time is to have your fluids changed.

 

ABS Safety Precautions

ABS Safety Precautions

Problem: Potential safety risk and possible component damage

Cause: Not adhering to proper safety precautions when servicing ABS equipped

 

Solution:

• NEVER open a bleeder valve or loosen a hydraulic line while ABS is pressurized. The accumulator must be depressurized in accordance with individual manufacturer’s repair instructions.

• NEVER disconnect or reconnect any electrical connectors while ignition is on. Damage to ABS control unit may result.

• ONLY use specially designed brake hoses/lines on ABS equipped vehicles.

• DO NOT tap on speed sensor components (sensor, sensor rings). Speed rings must be pressed onto hubs, NOT hammered onto hubs. Striking these components can cause demagnetization or polarization, affecting accuracy of speed signal returning to ABS control unit.

• DO NOT mix tire sizes. Increasing the width, as long as tires remain close to the original diameter, is acceptable. Rolling diameter must be identical for all 4 tires. Some manufacturers recommend tires of the same brand, style and type. Failure to follow this precaution may cause inaccurate wheel speed readings.

• DO NOT over tighten wheel lug nuts. Bent rotor or brake drum may occur, which can lead to inaccurate wheel speed readings.

• DO NOT contaminate speed sensor components with grease. Only use recommended coating when system calls for an anticorrosion coating.

• When speed sensor components have been removed, ALWAYS check sensor-to-ring air gaps when applicable. These specifications can be found in each appropriate article.

• ONLY use recommended brake fluids. DO NOT use silicone brake fluids in an ABS equipped vehicle.

• When installing transmitting devices (CB’s, bluetooth, etc.) on ABS equipped vehicles, DO NOT locate the antenna near the ABS control unit (or any control unit).

• Disconnect all on-board computers when using electric welding equipment. Alternate method: Place welding clamp as close to work as possible.

• DO NOT expose the ABS control unit to prolonged periods of high heat (185‘F/85‘C for 2 hours is generally considered a maximum limit).

• Do not disconnect the battery to clear codes. This only works on a small number of vehicles.

• Do not overfill the brake fluid reservoir. Follow manufacturers instructions.

Vacuum Booster – Partial Brake Assist Diagnostic Tip

Vacuum Booster – Partial Brake Assist Diagnostic Tip

Problem: Poor brake assist – lack of stopping power or having to depress the brake pedal harder than usual to stop.

Solution: If you suspect the brake vacuum booster of providing only partial assist use the following steps to determine if it is a vacuum supply problem or a booster problem.

 

  1. Pull another vehicle of similar engine size next to the vehicle in question and connect that vehicle’s vacuum source to the suspect booster. I usually use an old piece of air line for this purpose.
  2. With the new source vehicle running apply the brake pedal in the suspect vehicle and check for a change in brake assist. If no change is felt then the booster is likely the culprit. If there is a change in the assist (pedal feels normal) then the vacuum plumbing is likely the problem.
  3. If the vacuum plumbing is the problem then closely inspect the components between the booster and the vacuum source to locate the problem.

More info: The vacuum booster has proven to be one of the most reliable parts in the brake system. This reliability has caused many technicians to overlook the booster as a potential source of brake problems. The booster is also high on the list of unpleasant parts to install. With this in mind it is a good idea to make sure the booster is the source of the problem before installing another unit.

Unfortunately this article does not allow a full explanation of the inner workings of a booster but you do need a basic idea of what is going on inside to allow accurate diagnosis. The main components inside a booster that control the assist function are the air and vacuum valves. The position of the valves determine what stage the booster is in. There are three stages of booster operation – unapplied pedal (no assist), applied pedal (assist) and hold (isolate assist). When a vehicle is running and the brake pedal is not applied the booster is in a suspended state. The vacuum valve is open and the air valve is closed causing the diaphragm to be “suspended”. When the brake is applied the vacuum valve closes and the air valve opens. Closing the vacuum valve isolates the boost chamber from the vacuum chamber. Opening the air valve allows atmospheric air to enter the boost chamber. The difference in pressures on either side of the diaphragm is what produces the assist. When the driver is at a stop light the pedal pressure is usually reduced causing the booster to go into the hold mode. During the hold mode the air valve closes and the vacuum valve remains closed. This isolates the air in the boost chamber until the driver releases the brake pedal.

Pressure Testing Brake Hydraulic System Tips

Pressure Testing Brake Hydraulic System Tips

To properly use the results of a pressure test it is best to first understand the pressures generated during different types of braking and the function of the different brake valves used in the system.

You will need to obtain a brake hydraulic pressure test kit similar to the image above

Because most manufacturers do not publish pressure specifications it is often necessary to use generic values. Typically the hydraulic pressure generated during light to normal braking will be from 300psi to 500psi. Panic braking is generally considered to start at about 600psi. The proportioning valve will start to limit pressure to the rear brakes at this time. If a full panic stop is taking place the proportioning valve will limit the rear brake pressure to about 800psi while the front brakes will climb to between 1500psi to 2000psi. The psi numbers presented here are averages based on many tests performed on different vehicles.

Two types of pressure testing are common, checking the front to rear brake pressures and checking an axleʼs side to side pressures. The uses of each of the tests is explained below:

Front to Rear pressure for a properly operating system

Checking front to rear pressure:

Performing a front to rear pressure test can be done to help diagnose the following conditions:

  • Proportioning valve malfunction – Diagnose the cause of rear wheel lockup during panic braking or possibly a proportioning valve causing a restriction (wonʼt reopen after release).
  • Premature front brake pad wear – Pressure tests are used to determine if a lack of rear braking is related to the cause of front pad wear.
  • Height sensitive control valve diagnosis or adjustment – These valves usually incorporate pressure tests in the adjustment procedure and can be diagnosed using pressure gauges.

Side to Side pressure for a malfunctioning system

Checking side to side pressure:

Performing a side to side pressure test can be done to help diagnose the following conditions:

  • Brake pull – different hydraulic pressures results in different clamping forces and can result in a pull
  • Side to side pad wear differences – if the pads on one side of an axle are wearing faster than the pads on the opposite side

Performing a Front to Rear Pressure Test

  1. Connect the gauges using the manufacturerʼs instructions. Most pressure gauges connect to the caliper or wheel cylinderʼs bleeder screw hole (See Figure 85.4). Make sure to properly bleed each gauge hose.
  2. Place the gaugeʼs memory needles on zero.
  3. Start the vehicle. Apply the brake first using light to moderate force as if making a normal stop. Note the pressure readings, under this pedal force the front pressures should not be over 500psi in most vehicles. Compare the front and rear pressure readings. At this pedal force they should be equal or near equal. If equal continue to next step. If there is a large difference with the rears being substantially lower than the fronts there is a potential problem. The list of possible causes will depend on the system configuration. The list will include:
  • Restricted proportioning valve
  • Restricted brake hose to the wheel or axle
  • Restricted steel brake line
  • Out of adjustment or restricted height sensitive control valve
  • Restriction in ABS modulator

 

Preventing Damage to ABS Modulators During Brake Pad Replacement

Preventing Damage to ABS Modulators During Brake Pad Replacement

Many of us are unaware that every ABS modulator is equipped with multiple filters. These filters can be placed in the inlets, isolation and dump valves and pump or motor. The filters are designed to keep the ABS unit free of debris. Below you can see a few examples of these filters. Most filters are a very fine screen mesh while others are a more course metal mesh. These filters are unserviceable.

Because these filters are unserviceable it is very important to keep them clean. Dirty filters can lead to dirty particles entering the ABS unit. Particles can clog ports and keep actuators from properly sealing. You can inadvertently send sludge and dirty particles up into the ABS unit by depressing a caliper piston too quickly.

This is a brake master cylinder made from acrylic. You can see that it is clean and looks to be capable of performing its proper function.

This is the same acrylic master cylinder with the addition of sludge filled brake fluid. When the caliper piston is depressed too fast it stirs up sludge and quickly sends it back up through the brake system. This sludge can clog ports and malfunction the ABS unit.

There is a simple solution to help prevent sending sludge up into the ABS unit. First, if you have a line lock tool and are able to open the bleed screw then use it to block the brake hose. Then, while depressing the caliper piston, open the bleed screw to allow the brake fluid to escape. Your second option is to not open the bleed screw and don’t block the brake hose. This must be done carefully, but if you take at least 60 seconds to slowly depress the caliper piston then you normally will not stir up any sludge or debris. This will help to keep the ABS filters, ports and actuators clean.

Tech tip: When changing brake pads, take at least 60 seconds to slowly depress a caliper piston. 

Rotors, Brake Hoses and More

Rotors, Brake Hoses and More

Brake Service Basics

With everything that could go wrong, servicing brakes can sometimes feel overwhelming. Over the years we have found if we keep it simple and use tried and true service methods your brake work can be very successful.

The following pictures and text present brake service repair tips and methods learned over the years or shared with us from seasoned professionals.

Line Locks

Professional brake service people normally use line locks like the one shown. Line locks are diagnostic tools in addition to being service tools. If you are changing a caliper and don’t want the system to run dry because the hose is dripping constantly then block it off with a line lock tool. There are several types. Just don’t use locking pliers.

Valve Stem Block

If you have a “banjo” type of hose to caliper connection you can block the fluid flow while changing the caliper by inserting a valve stem into the large bolt opening of the hose.

Use Soap and Water

If you have your rotors turned wash them off with soap and water before reinstalling them. Even if they have been sprayed with a brake clean type of product it is best to wash them with soap and water. Brake cleaning products remove oil based film but it takes soap and water to really clean everything.

Rotor Coating

Some new rotors have a petroleum coating while other have a unknown coating or some even say to remove from the box and install on the car. Some coatings are supposedly ok to make contact with a new set of pads and do no harm, but many knowledgeable professionals still wash all rotors before installation. Most professionals suggest washing new rotors with a brake clean type of cleaner then a soap and water wash. This is the safe way to be sure they are really clean and ready to use.

Rotor Run Out

If you see a shiny spot on a rotor such as the one shown it’s an indication of excessive rotor run out (wobble). This problem may have been caused by either rust and scale behind the rotor hub face, the wrong method or value of torque when tightening the wheels or hub run out that caused the rotor to not track at zero run out.

Hanging Caliper

Don’t ever hand a caliper by its attaching hose. Use a wire hook, a flexible wire wrap or something to positively hold it from hanging on the attaching hose.

Excessive Heat

The separation of the hose from the crimp holding the attaching end was caused by excessive heat. In this case a torch was used to heat the end to enable the flare nut on steel brake line to be loosened. While not common, extremely high brake operating temperatures can also cause this connection to be weakened or fail.

Rust Build-Up

Just because a hose looks ok doesn’t mean it is. This hose has an internal restriction caused by rust and scale building up on the inside of the wrap around clamp holding the flexible hose in place. As the rust formed it caused inward pressure on the hose until it squeezed the hose enough to block the small fluid opening inside. This caused a brake pull to the other side of the vehicle. Appearances can be deceptive.

Locking Plier Problems

This hose also appears to be ok. There are no external cracks yet the vehicle has a pull to the opposite side. What has happened is someone at one time used locking pliers instead of a line lock on the hose. This cause the internal layers of the hose to break down and a piece of the internal liner has broken free and is now blocking the fluid from reaching he caliper.

We hope you learned something that can make your work day a little easier. Please let us know if there are any specific repairs or tips you want us to explore in the future.

For questions or comments you can email me at jt@brakebleeder.com

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