Disappointment is the word that describes my reaction to reading at The Car Connection that there is a trend afloat to reduce the use of coolant temperature gauges. The article dealt specifically with Mazda's decision to use a cold light in the new 2012 Mazda5.
I don't take issue with the idea of tweaking the driver's subconscious mind with a "cool blue" glow on the dash to discourage excessive revving of the engine when the vehicle's engine is hovering around the "C". It's the other end of the spectrum, the part that resides in the neighborhood of the "H", which seems to be getting short shrift.
Since the engine damage caused by going crazy on a cold engine is a bit more subtle and only detected over time, it would seem that the consequences of a hot engine would deserve even more consideration. I know that the proponents of gauge exclusion will offer the use of a "Hot Light" as a defense. You know there is a reason that these indicators are called idiot lights.
There are observant, conscientious drivers who actually care about the welfare of their investment in their car and monitor engine condition while driving. I know because I talked to one this week who described a climbing temperature gauge which he used as a tool to nurse a car home safely by stopping periodically before it began to run hot.
So that is one occasion- the car beginning to overheat- when the gauge can make a big difference. Another has to do with lack of heat in the car. As mentioned in The Car Connection piece, being able to monitor the actual coolant temperature helps in diagnosing a problem with the thermostat. If the gauge climbs but the output of the heater is minimal it is usually the sign of one of two conditions. The thermostat is either stuck closed or there is insufficient coolant to heat up the cabin.
Since there is not enough coolant flowing through the heater core in either instance no heat can be provided to the passenger area and at the same time the engine will run hot. This would lead to the conclusion that the cooling system has a leak or the stat is indeed not opening. But the initial step to these diagnoses is a rising temperature gauge.
At a time when the conventional wisdom is that vehicles are being made better than ever, which is supported by data showing the increasing longevity of cars and trucks, it seems that a decision like this is either based on shortsightedness or the very fact that cars are lasting as long as they are.