Normal Engine Temp?

Grumpy Bear · June 7, 2020

13 hours ago, Paul_’18 Silverado said:

Is it normal for the temp gauge to fluctuate?

temp in picture is from idling and revving in park up to 3-4000 rpm with outside temp being 20deg C. It also climbs when accelerating up hill with no load at same outside temp of 20deg C...it does go back to a needle width below 100 right after

called dealer, said it’s normal up to 120deg C. Anyone experience this?

2018 Silverado 5.3 with 27000km

Posting in this forum I assume your truck falls in these years of production. The factory thermostat is 207 F (97 C). They have a 3 degree tolerance so it is possible that it is just starting to open at mid gauge. The gauge itself is a bit of joke. 75 C will actually be closer to 40-45 C. Pretty close at mid gauge though. You're observing the cycling of the thermostat. In slow speed traffic ,city or behind a wreck the thermostat gets fully open but the radiator isn't large enough to hold the set temperature because new cars/trucks don't have FANS that are belt driven. As noted earlier the thermal switching temperature is 221 F / 105 C but even then the fan is graduated in speed so given a hot day it will climb until there is enough fan speed to pull enough air to cool it back to under the switching point then just cycle between the two. It will continue this until you get enough free air in the radiator at a speed above 50 mph / 88 kph (roughly) to 'get right' which isn't right but it is the design.

There are solutions such as colder thermostats but without getting into the PCM/ECM and resetting the fan speed lower slow work temperatures will not change and hover the switching temperature. However it will take longer for the system to get that hot first run of the day.