Thermostat problem?

[Lspoo19]

I have 2016 with 5.3. I’ve noticed even driving highway speed for extended time my temp gauge will not stay at 210 on the gauge. Any slow down for stop light or other light city driving the temp will drop some on the gauge. I’m assuming I should be maintaining the normal operation temp no matter ambient temp? Anyone else run into this thinking it’s a thermostat stuck in between.

[mookdoc6]

41 minutes ago, Lspoo19 said:

I have 2016 with 5.3. I’ve noticed even driving highway speed for extended time my temp gauge will not stay at 210 on the gauge. Any slow down for stop light or other light city driving the temp will drop some on the gauge. I’m assuming I should be maintaining the normal operation temp no matter ambient temp? Anyone else run into this thinking it’s a thermostat stuck in between.

Time to replace it's all in 1.  Housing included 35-40.00 bucks

[SARNCAN]

I have 2016 with 5.3. I’ve noticed even driving highway speed for extended time my temp gauge will not stay at 210 on the gauge. Any slow down for stop light or other light city driving the temp will drop some on the gauge. I’m assuming I should be maintaining the normal operation temp no matter ambient temp? Anyone else run into this thinking it’s a thermostat stuck in between.

Yes, that means seals starts to leak/crack allowing the fluid to circulate and not being fully closed.
Just replace it with a new one if that bothers you.

[It's Tim]

Easier to just replace everything...

Coolant

Hoses

Thermostat

[Grumpy Bear]

2 hours ago, Lspoo19 said:

I have 2016 with 5.3. I’ve noticed even driving highway speed for extended time my temp gauge will not stay at 210 on the gauge. Any slow down for stop light or other light city driving the temp will drop some on the gauge. I’m assuming I should be maintaining the normal operation temp no matter ambient temp? Anyone else run into this thinking it’s a thermostat stuck in between.

How many miles do you have on this motor? 

[Lspoo19]

1 minute ago, Grumpy Bear said:

How many miles do you have on this motor? 

Just under 42k

[Grumpy Bear]

1 minute ago, Lspoo19 said:

Just under 42k

It's not that a thermostat can't fail in such a short time but for the factory one this is unusually short. How much short of straight up is the needle? Got a photo?

[Lspoo19]

Here is about where it normally stays at if I were to jump off the highway

[Grumpy Bear]

That's about where mine runs all the time but I'm running a 170 F thermostat so that is low. What part of the country to you live in? Mine would get that low on really cold days with the factory 207 F stat in it. 

 

On the thermostat housing is a small bleed line that goes back to the radiator catch tank. This is a minimum flow bypass around the thermostat to 1.) provide enough flow to keep the pump happy. 2.) Get hot water to the thermostat so it operates correctly as the thermostat itself does not have a bleed or 'jiggle pin" for this purpose as the Gen 1 motors had. IF you live an an area where it gets really cold then it is possible that this alone will keep the motor cool under light loads...non-highway.  

 

Of course it still could be the stat seal as was suggested earlier. They are not the hard to change. 

[Lspoo19]

19 hours ago, Grumpy Bear said:

That's about where mine runs all the time but I'm running a 170 F thermostat so that is low. What part of the country to you live in? Mine would get that low on really cold days with the factory 207 F stat in it. 

 

On the thermostat housing is a small bleed line that goes back to the radiator catch tank. This is a minimum flow bypass around the thermostat to 1.) provide enough flow to keep the pump happy. 2.) Get hot water to the thermostat so it operates correctly as the thermostat itself does not have a bleed or 'jiggle pin" for this purpose as the Gen 1 motors had. IF you live an an area where it gets really cold then it is possible that this alone will keep the motor cool under light loads...non-highway.  

 

Of course it still could be the stat seal as was suggested earlier. They are not the hard to change. 

In the Midwest been negative temps all week. I’ve still noticed it when it’s 60 out. I’m sure the bypass is what’s causing the cooler temp 

[JONBLARC7]

Anybody know the part number for the colder CTSV or ZR1 thermostat.

[Grumpy Bear]

1 hour ago, Lspoo19 said:

In the Midwest been negative temps all week. I’ve still noticed it when it’s 60 out. I’m sure the bypass is what’s causing the cooler temp 

Then change the thermostat if you're sure. You know your truck better than anyone else, right? 

 

[Grumpy Bear]

On 2/12/2021 at 1:21 PM, JONBLARC7 said:

Anybody know the part number for the colder CTSV or ZR1 thermostat.

Engine Coolant Thermostat Part Number:  12T020E Product Notes:  Engine Coolant Thermostat All; Temperature 194F; Incls housing, thermostat, & seal; OEM Recommended Temp; Std   Per Vehicle: 1; Years: 2016-2017

Edited February 14, 2021 by Grumpy Bear

[Skytrekin]

Not hard to change, their are some youtube videos out there.

I didn't drain the radiator, just took off the hoses and changed the assembly, and topped off the coolant. Mine did the same thing at 50k miles. 10mm socket and slip joint pliers, and common screwdriver for clamps

[Grumpy Bear]

On 2/12/2021 at 3:13 PM, Grumpy Bear said:

Engine Coolant Thermostat Part Number:  12T020E Product Notes:  Engine Coolant Thermostat All; Temperature 194F; Incls housing, thermostat, & seal; OEM Recommended Temp; Std   Per Vehicle: 1; Years: 2016-2017

The above number is the ACDELCO GOLD/PROFESSIONAL (lower priced, lower quality) 

 

The below number is the ACDELCO GM ORIGINAL EQUIPMENT

 

Engine Coolant Thermostat Housing
Part Number:  15-11113
Product Notes: 

Engine Coolant Thermostat Housing
All; V, VIN: 6, Eng Code: LT4*

 

Per Vehicle: 1; Years: 2017-2017