Is Engine knock harmful?

Yes, it can be very harmful. The combination of intense pressure waves and resulting high cylinder temperature can induce piston or ring failure. Under high-speed or high load conditions knock can lead to pre-ignition (pinging), which then accelerates engine destruction. Pre-ignition and detonation are the major cause of headgasket failures. Major cause of pinging or detonation in the engine are:

1. Poor fuel quality

2. High cylinder temperatures caused by lean fuel mixtures, failed or mis-adjusted engine controls or high engine temperatures cause from cooling system problems.


Fuel Additives

Gasoline additives such as de-icers or octane boosters usually do more harm than good. They contain alcohol which changes the volatility of the gasoline and may result in performance or hard starting problems. Although gasoline de-icer may be helpful when a small amount of water is introduced into the fuel, this condition is very rare under normal driving conditions when using quality fuel because of the sealed fuel systems on cars built in the last 20 years.

Fuel system cleaning additives can in some cases remove gum from the fuel tank and flush it into the injetors causing even more problems. Higher grade fuels contain detergents that will keep injectors, valves and fuel system clean if used regularly.

In the long run it is more economical to buy quality fuel to begin with, instead of trying to add expensive additives to accomplish what you fuel should be doing for you in the first place.


Fuel Pump Care:

GAS TANKS should be kept at least 1/4 full if your vehicle has fuel injection. This keeps plenty of fuel for the electric pump, which depends on a constant supply to lubricate its internal parts. Running low on fuel causes the pump to wear out more quickly. Dirty fuel filters can also cause early pump failure from overheating.

keeping Coolant Clean

A survey of ASE-certified automotive technicians throughout th enation determined that coolant is the second most neglected vehicle maintenance item. Coolant should be checked for both strength and also pH level at each service. To check the pH level, you should use a chemically treated test strip, which can be purchased at most part stores.

The average pH level range of typical coolant is around 10.5. When diluted with water, it drops to 8.5 to 9. A pH level at 7 or lower can lead to both excessive corrosion and electrostatic discharge (ESD). With ESD, the PCM can receive false readings from the electronic cooant temperature sensor, which can lead to poor fuel economy and setting off of diagnostic trouble codes. With a low pH level, the coolant becomes acidic, which can cause hose, radiator and water pump failures.

So the bottom line is that if coolant is contaminated or the additives are depleted, flush the system. The use of low or no silicate coolant at a 50/50 ratio is best. You and your customer will be satisfied with a job well done.

Also, radiator caps play an important role on automotive cooling systems. They can lead to radiator or water pump seal damage. The job of the cap is to hold pressure on the system, which raises the boiling point of the coolant and prevents steam bubbles from forming inside the cooling system.

Caps should be pressure tested each time the system is serviced. Most caps will range from 4 psi to 18 psi.

When testing the cap, it should hold pressure for two minutes. If it doesn't the cap should be replaced. The condition of the gasket in the cap also should be inspected for swelling or tears that could lead to coolant loss and engine overheating.

Courtesy Airtex Automotive Division.