Air in the Coolant System – Will cause the vehicle to overheat.
Coolant in the Cylinders – Causes a rough idle. Sooner or later severe engine damages may result. Over the time damage will occur leading to engine failure and costly repairs.
Compression Loss – Will causes a miss fire issue, rough idle, lower the power output of the engine? Fuel economy will slowly diminish along with the compression.
Coolant in the Oil – When they mix it turns to thick good; it will not be able to pass though oil passages to lubricate the engine which causes metal on metal contact. Over time mechanical failure will occur. Water displaces oil, leading to premature bearing damage.
Oil in the Coolant – Sign of a head gasket going bad and or an oil cooler leaking.
Coolant Leaks – There are quite a few components to your cooling system. Which ones over time don’t leak? Your vehicle might say not to change your coolant till 100,000-150,000 miles on some applications. But going that long some coolants will breakdown, overtime when coolant ages sometimes it becomes acidic P.H. wise. What that does is eaten through parts from the inside out, including your head gasket. That is one trick manufacturers use to get you to trade in your vehicle for another. Typically when a head gasket goes bad the price can be so costly to fix, sometimes you can just buy another vehicle. Changing your coolant sooner than later (preventive maintenance) pays for itself and helps your investment lasts.