Temp and Volt Gauge Readings - normal?

Jimmy-Mack · March 28, 2021

My normal temp gauge reading is running a tick over 210. I'm not towing anything yet and it's only 60-70 degree ambient temps.

Also my volt gauge reads 15 -16 volts most of the time. This seems high for a 12 volt system? 13.6 - 14 would seem normal. I realize the truck has a intelligent alternator and will reduce the volts to around 12 volts on trips for fuel economy .

Dealer is saying both are normal?

What is everyone else seeing?

Thanks

Wxman · March 28, 2021

Less than 500 miles on my '21 gasser. Yes, my temp gauge runs barely higher than the 210 mark. Needle still touching but higher than 210. Volt gauge does seem to run higher than my '17 5.3L, but I have seen it 'go down' in the right conditions. This truck has the aux battery and i don't know if that affects it or not.

redwngr · March 28, 2021

Seems to be a common voltage observation on brand new ones.

The last few new GM's around here have done that initially, and once they got some time/miles on them the high reading was much less common.

The explanation of all the things the computer considers when commanding the charging system is multi-pages long.

L8T · March 28, 2021

My coolant temp is usually 200 or a bit below but I haven’t seen over 60F ambient.

That voltage seems normal.

mrjulian416 · March 29, 2021

I'm seeing coolant temps just above 210 at full operating temperature.

I see voltage vary from about 15 down to 10 depending on driving conditions and how long its been since starting.

Jimmy-Mack · March 30, 2021

Thanks for the replies. Seems to be the new norm then.

powderMonkey · March 31, 2021

I have a Banks iDash and have some interesting info for you guys!

I cold start the truck in my garage this past Sunday having not been driven in several days, and the Banks shows ECT (eng coolant temp), EOT (oil), and TRNS (transmission) temps all between 55-57F, which is the ambient temp in the garage. On the Banks, the ECT rises more quickly, with Oil and Trans temps warming more slowly. Get this - the factory gauge in the truck on the dash is at the 210F+ a hair mark, and on the Banks iDash ECT is at 165F, 166F, 167F climbing along as normal. The highest the Banks has shown me so far is about 199-205F. It fluctuates / changes info in real time, very high refresh rate. it's fun to watch!

I truly believe the Banks is accurate, and the factory temp gauge needle probably sits in that 210F spot from 165F thru whatever temp the fan kicks on at probably 215-220F? The average person - they just want to see that the engine temp is 'Normal' so the needle never really moves.

I've also got the Banks showing me Throttle Position %, and ECU Commanded Horsepower. Pretty interesting to look at. Take off on a highway stoplight, just a normal take off I use about 23-27% throttle. It shows 80-100HP. Once at 60mph it takes about 60HP to maintain that speed. An aggressive take off will show 240HP and like 48-56% throttle. The Banks iDash is a slick little dude... ; )

powderMonkey · April 13, 2021

I drove my Z71HD again on Sunday for the first time in a week so I paid attention to the temps again. What I noticed was the GM dashboard temp gauge came alive (up off the low 160F mark) when the actual coolant temp was about 127F. And again, GM gauge is at it's TDC 210F spot when in reality the coolant is at 160-165F.

Wxman · April 13, 2021

Hmmmm, interesting. I wonder if they are reading from the same spot in the flow, or if there is more than one sensor and they aren't reading from the some one.