As everyone probably knows, the coolant gauge isn't really a gauge in our cars. Its an idiot light that only moves up to normal after a cold start and then remains there unless there is a large change in engine temperature. This is why the gauge doesn't move when going up hill on a 110 degree day with the AC on. A few weeks ago I started to notice that coolant temp readout on my scangauge was reading over 200 degrees during normal driving and then last week it stayed at 220 when 188-195 was what was being recorded since getting the gauge over 3 years ago. My aux fan started chiming in as well, cycling on and off as the coolant temp soared past 225 degrees. Meanwhile, the temp gauge on the car stayed at the usual 50 percent. Turned out I had a bad thermostat. I'm at 105k and decided to change the coolant and throw a new thermostat in. Problem fixed and I would never have known about it if I had just relied on the regular gauge.
The buffering of the coolant gauge
- Thread starter 5zoom
- Start date
Well, I didn't know that. Lame.
phunky.buddha
Booga Booga?
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- DFW TX
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- No mo MZ5 want MX5
Quite a few cars are actually like this now... my S2000 (03 model) has LEDs for the temp gauge- and the "center" segment covers about a 40 degree range while the rest are in much smaller increments. Not too helpful to know when you're starting to overheat- just when you're already in "oh crap" territory. 
The Volvo is like that too. Guess too many people complained about idiot lights, so they changed it into an idiot gauge instead to appease the masses who like to feel like they know what's going on but don't want to put in the effort to REALLY know whats going on. Just like the incredible surge in call centers about 15 years ago.
phunky.buddha
Booga Booga?
- :
- DFW TX
- :
- No mo MZ5 want MX5
Sounds about right.
Jasonjames
Member
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- Mazda 2002 BJ Astina 323 1.8 L
Interesting. Maybe they are trying to stop people panicking if the coolant-gauge climbs slightly. A good cooling system should have enough "head-room" or spare cooling capability [meaning the t/stat is not quite fully open during everyday driving] to handle most demanding situations without causing coolant to get hotter. All depends on how clean the water-jacket [around the motor] and radiator is. Since the intro of Glycol based coolants, a dirty system is not as common as in earlier years.
