Temperature gauges


I’m a 60+ year-old car-guy. I’ve owned lots of cars, foreign and domestic, cheap and pricey. My last 4 purchases have been Hondas/Acuras. Modern cars, if you believe the temp gauges, seem to warm up extremely fast, even in cold weather, and the engine temp seems to never vary, even when you’re in stop-and-go traffic on a 95 degree day. Are the gauges lying to us?


I don’t think so. Cars are designed to warm up quickly because they pollute more until they are warm. Therefore, the quicker the engine warms up the less pollution it emits.

Modern cooling systems, assuming they are functioning properly, are VERY good at maintaining a specified temperature.

Why don’t you believe the gauge?


Well, it seems to stay too steady, even under severe conditions. This summer, for example, I was stuck in traffic in my '05 Acura TL (a terrific car). I basically idled for over 30 min. at almost 100 degees with the AC full blast. I was ready to cut off the AC and roll down the windows, but that gauge never budged! Also, this car warms up on cold days easily twice as fast as say, my 1980 Mercedes did, under the same conditions. I know modern engines are aluminum, they have efficient coolant systems and radiator fans, but nothing seems to affect the temp, even slightly.


Well, it seems to stay too steady, even under severe conditions

That also is part of MC’s response. To keep the engine clean they need to keep it at an even temperature too hot is one problem too cold causes other pollution problems. They use a number of tricks to keep it even.


The power per displacement is higher so power per mass of metal in the engine is higher. Power is proportional to fuel combustion and so is heat. Thus heat/metal mass is higher. The heat/coolant volume in the block will also be higher. This makes the whole package warm up faster. The only thing you need to keep the thing cool in hot weather is a large enough radiator and fan and a working t-stat. Did the Benz have an electric fan? That can make a big difference at idle or in crawling traffic.


If your gauges are not digital, and stay on after shutting off the engine, you should see a temporay rise after shutting off the engine. When the water pump stops, even if the fan is still running, the residual heat in the engine block should meake the temperature rise. If that happens, your gauge is really working.

Modern cooling systems are part of the emission guarantees the car compnies have to provide for 50,000 miles at least. So they make them large enough to cope with high heat as well as provide quick warmup. Previous poster is right that the pounds of metal per 100 horsepower has dropped dramatically, so you now have much faster warmup. I used to specify vehicles for the Arctic. We always picked the smallest standard engine, since you could not go very fast there, and the large engines took forever to warm up at -50F.


You’re thinking of the "old days, " which are gone. Modern cars don’t overheat in traffic, regardless of the ambient temperature. Manufacturers test their cars in desert conditions, arctic conditions, etc., to make sure you and I can have a trouble-free commute back and forth from work.

Isn’t it wonderful?


The gage will go up if you are getting hot. You usually don’t have trouble anyway unless the temperature outside goes over a hundred and change. Not with a car in good shape.


No, I think the gauges are accurate. I think what you are noticing is cooling systems that are designed better. Also consider that engines are designed better and cars are lighter, especially the Hondas and Acuras you have been driving.