Where did the coolant go?

A common occurrence is to check the coolant level on a hard-working gas or diesel engine and to find that it is low while there appears to be no leak. You top it off and carry on but with an uneasy feeling – is a severe engine problem looming?

The coolant had to go somewhere. The answer, in most instances, is probably not. The cooling system is working the way it should. When you work an engine hard, it uses more fuel, but what we do not think about is the heat that is created by the fuel consumption.

The thermal load on an engine is directly linked to the rate of fuel burned. The heat needs to be absorbed by the coolant to prevent thermal distress.

The job of the liquid is to remove heat from the engine. The task of the radiator is to remove heat from the liquid. It is the liquid that cools the engine and not the radiator.

Under high thermal load, the coolant in the water jacket of the cylinder head undergoes a regiment identified as nucleate boil. When nucleate boiling occurs, the most effective heat transfer to the liquid happens.

When the engine is lightly loaded, the surface temperature of the combustion chamber is usually low enough that boiling in the water jacket does not take place. After the coolant boils, it is pushed from the site via the system pressure and water pump. It takes heat with it and will recondense as it cools.

This boiling and recondensing consume the additive package along with the water that turned to steam.

The mystery of the missing coolant is now solved!


Is a Diesel Tuner Right For You?

The sentiment of a famous country song says it all, “There can’t be a girl too pretty or a car too fast,” or in our case, a diesel engine that is too powerful!

The promise of added performance with a diesel tuner is easy to fall prey to. Before you invest in a diesel tuner, you need to understand how it works and its possible ramifications. The modern diesel engine replaced the pump-line-nozzle system with common-rail electronic injectors and an ECU (engine control unit).

The ECU can be recalibrated to alter the timing and length of the injection pulse along with the boost pressure. This is the source of the power gain.

The calibration a diesel tuner employs is more aggressive than that fitted by the engine manufacturer. Engine power is produced by the pressure created during the combustion of the fuel. The higher the power, the more heat generated, and the greater the cylinder pressure.

Heat and pressure when excessive will end up hurting the engine.

The logic of the engine manufacturers is to build an engine and transmission that can take more power than the tune produces. It is like building a truck that can carry more weight than it is rated for – it is the buffer for when it is overloaded. An aggressive high horsepower tune either diminishes or removes the safety barrier.

A tune identified for towing offers the best of both worlds; better throttle response, increased power and fuel economy, while still being safe for the engine.

If the truck is worked hard often, then I suggest keeping the stock calibration and just go a little slower up the hills.

Why risk an expensive repair?