Coolant reservoir level

[dsr2]

Hi, I have a 2003 Trailblazer with 4.2 engine. I noticed that the level in my coolant overflow tank never seems to change, even after being driven. Is it supposed to go up over the FULL line when it gets hot? Mine is always at the Full Cold line. Thanks.

 

[Mooseman]

It will go up if the cap lets off pressure. That usually happens when it gets fairly hot. If everything is working well and keeping it cool, it might not let off pressure. Or, your thermostat is stuck open and overcooling. What are your temps like? If it hangs to the left of 100c/212f, it might be running cooler than it should. If you have access to scanner that can read live data (not just a code reader), get the actual temps from the PCM as the gauge is a guesstimate filtered by the PCM.

 

[dsr2]

Thanks for the reply. My temperture gauge reads at 1 hash mark to the left of 210 F. I did check it using a scan tool, and the readings were steady at 195 on the scan tool (on freeway, but outside temperature was only about 78 F). Is this within the normal/acceptable range? Note that on very hot days (around 95 degrees or more) the gauge does go up to 210 occasionally.

 

[Blckshdw]

You're reading at the acceptable minimum temp. My EXT does the same thing here in FL, unless I run the AC or get in heavy traffic, then I get up around 205-210.

 

[Mooseman]

Yep, normal. And I wouldn't worry about the reservoir not moving. As long as you're at least at full cold, you're good. Also shows your cap is holding pressure.