So the rumor that they were screwing with the ect gauge so it reads cooler is false??
YES, very literally false.
The GM ECT gauge behaves consistently with just about EVERY coolant gauge ever produced, to be informative without drawing attention to itself
when thermostats cycle. If anything, ours is more sensitive than most. Next time you are not in a duramax take a look. Japanese, German, Swedish, thay are all the same. The gauge rises very quickly, within 5 minutes, to a fixed point around 20 degrees shy of the thermostat cracking temperature, and never moves. I have driven civics that ran at 200-230 degrees all day in Phoenix city traffic, electric fan cycling, with oil at 300 degrees, and nary a sign of anything out of the ordinary.
ALL these gauges are INTENTIONALLY fixed with a large dead zone, 30 to 50 degrees wide, where the needle parks itself forever, moving only to illustrate what the OEM intended it to show, severe undercooling or overcooling of water based coolant. This is done because it is a passenger car, not the Space Shuttle Challenger, and because the gauge is not a diagnostic tool. OEM's hate gauges because they create work. Intended only to be mildly more informative
than a dummy
light, with graduated markings that promote the same intelligence as most of its operators (
a forum cross=section is not representative of this IQ, most
of whom are quite a bit more knowledgeable than average tow Joe
GM changed the deadband a year ago, in response to ECT complaints, many of which came from people whose vehicles only got warm. NOT OVERHEATing, as in no loss of coolant, just get hot. With some exceptions, few actually get coolant to spill, but many get the DIC notification. The corporate response..."lets pretend the problem doesn't exist, mask it more and we will reduce these nuisance calls by 50%". That is what I would expect from GM, there is no money in fixing issues when the check has been cut. Ethically, its a debate, but the acts of GM to deal with the service call issue, are very appropriate and common. Deny, deny, deny
These people came in and there was nothing GM deemed appropriate or cost effective to fix it. So they went with reducing the visibility of the issue. How? They deadened the warning system a bit more. Grandstanding conspiracy supporters say they added deadband to the gauge so it behaves ("lies
") more like a typical consumer oem gauge. Unproven, however IMO, irrelevant. They also raised incidence of audible alarms by 4 degrees, 244 to 248 IIRC, in one act. That much can be viewed in the ECM code.
The relevant fact is, if you get hot enough to spill coolant, the gauge WILL tell you beforehand. It has always done this, and GM did nothing to inhibit it from notifying the operator thus. The graduated markings are worthless, and they always were (like every oem gauge), just as they are in every other car out there. 160 is not 160, But 205 is 205 with +/-15 degree certainty.
A dummy light with trend information.