Do I really need a new thermostat?

[John105]

Larger capacity on an aftermarket radiator??? I only see that happening if you went out of your way for it, or if you bought the radiator for towing package that your vehicle didn't come with.

People Do this all the time with the LS430. It doesn’t matter vehicle is still going to run at same temp due to the thermostat. They somehow feel mo’ better

Maybe an exception is due to malfunction more capacity needed to be below spec’d temp with thermostat wide open

 

[Rhymingmechanic]

Is this new behavior, or is it a new-to-you truck that you're driving in cold weather for the first time?

If it's a change from previous cold weather, that would suggest a problem.

My first thought is that you need to read the temperatures with a scan gauge, or on the dash readout if the truck has that option. The gauge is probably not exactly accurate.

I thought my 2001 Silverado had a "real" gauge rather than a buffered one because the reading would change with different conditions. I learned otherwise when it got hot in the school pickup line one day. Next time, I brought along an old tablet with Torque Pro to read the actual temps. I drew the image below as I crept through the line. Black is the gauge, and red is the actual reading from Torque.

My drawing is a little inaccurate--the gauge actually has three small marks between the larger, labeled ones. Reading left from the middle/210, (assuming the actual three small marks) normal range is from the middle mark to between the third one and 210. Temperatures and the general locations on the drawing are accurate. That shows just how off the gauge is.

If it does need a thermostat, I would recommend getting the GM Original Equipment model, from a dealer or someplace like RockAuto.

 

[JRay’07]

Many modern ECUs will set a fault code for either the thermostat or ECT when the thermostat operates incorrectly. You can usually tell if the reading on the instrument cluster is rational or not.

 

[John105]

Not sure if it’s changed but I thought it was interesting 18 years ago when I got a BMW, there was no coolant temp gauge, rather an oil temp gauge. And even though my car has an external oil cooler, the needle is 3/4 up the scale at operating temp. Folks complained, so BMW introduced a new gauge where the scale was modified so at the exact same temp, the needle was in the middle. A lot is mental which is fascinating with analog instruments.

I do know where the temp needle falls on the other 2 cars, and really would feel uncomfortable if the needles were to move higher, or lower. Seeing as they have been the same 8 and 13 years respectively.

 

[RobbyDawg]

Proper engine operating temperature is important. If you’re remotely handy, the t-stat replacement is an easy DIY job and could be done for 1/4 of the cost you were quoted.

 

[Lubener]

Some consider the thermostat a maintenance item. Just get a new OEM or Stant one.

If it works, I see no reason to change it.

 

[Snagglefoot]

Just to be clear, 210 F is the normal operation temperature for this vehicle. If it’s lower than that when the heat is on chances are it is stuck open. Watch a You Tube video on changing coolant and a thermostat. This would be considered a beginner level mechanic job if you are interested.

Also, you can check the temperature with an infrared laser pointed temp gun pointed at the thermostat housing.

 

[John105]

If it works, I see no reason to change it.

This is what the Japanese indie told me when they did the timing belt job that includes the water pump. They stated in our experience, there is no reason to change it. But it's your money, we will spend it if you insist. So I didn't change it and now another 7.5 years has gone by and it's fine. I am the type that would be paranoid if the temp gauge needed changed. The job often is not as easy as when I was a kid and my dad had a GM 350.4 V8.

There is also a very good chance that the one made in 2005 in Japan, is more reliable than the one made who knows where in 2024, or then, 2017.