Coolant temp gauge fluctuates

[Daniel Brazzle]

52 minutes ago, MaverickZ71 said:

Think about this.  When you start the vehicle, if it has sat overnight, the coolant temp is ~ the temp of where the truck is parked.  Anywhere between 185F and 235 is considered normal operating temperature, with 260 and above overheating.  So if you're not seeing above 210, how could your radiator have possibly been damaged by the thermostat??

The way the TSB is stated it sounds like the thermostat is opening and closing to quickly which is putting stress on the radiator because the coolant is going from hot to cold too quickly. 

[MaverickZ71]

23 hours ago, Daniel Brazzle said:

The way the TSB is stated it sounds like the thermostat is opening and closing to quickly which is putting stress on the radiator because the coolant is going from hot to cold too quickly. 

I guess in modern vehicles, anything is possible.  But for instance, the temps here today are ranging from a low in the lower 70s to a high in the mid 90s.  So according to the temp gage in the truck, the coolant would be going from 70 degrees to 210 while driving and from 210 back down to 70 overnight, all without leaking, with cycles of 210 down to 185 or so over stops.  So if it can do that range cycle daily without leaking, I don't see how 185 to 210 and back would make it leak, unless you had a leak-prone rad to begin with.  Best of luck with your thermostat fix and hope you can then enjoy driving without worry.  

[Daniel Brazzle]

3 hours ago, MaverickZ71 said:

I guess in modern vehicles, anything is possible.  But for instance, the temps here today are ranging from a low in the lower 70s to a high in the mid 90s.  So according to the temp gage in the truck, the coolant would be going from 70 degrees to 210 while driving and from 210 back down to 70 overnight, all without leaking, with cycles of 210 down to 185 or so over stops.  So if it can do that range cycle daily without leaking, I don't see how 185 to 210 and back would make it leak, unless you had a leak-prone rad to begin with.  Best of luck with your thermostat fix and hope you can then enjoy driving without worry.  

Maybe the ones in the TSB change the temp a lot more than mine does. I don’t know because the TSB doesn’t say anything about temperatures 

[Swifty5]

On 6/24/2020 at 10:55 AM, Daniel Brazzle said:

I thought the the same thing but there is a TSB for over cycling thermostats which cause radiators to leak 

I had my 14' Silverado in for the smell of antifreeze and this is exactly what happened. Even though it is within operating temp, the thousands of cycles of different temperature cracks where the hoses connect on the radiators.