Thread: Is there to be a tube INSIDE the overflow tank?

97 Grand Prix GT

Issues:
1) visible brown sludge coating in radiator system
2) low coolant light is intermittent
3) temp spiked to RED after highway run yesterday

Note: car is not using standard DEX coolant. Sludge was still visible when using DEX. Been using a replacement for DEX for years. Had no problems until this past year.

Known outstanding problem: Coolant level remains constant at a "below full" level. After adding (little) coolant to full (top of radiator) and running, the coolant gets pushed out into the overflow tank. (such that after a highway run, when moving slowly in traffic, the temp gets very close to RED that I will roll down the windows & turn on the heat to help reduce the temp. (happened once last year)

After looking into it more, and finding online WHERE the low coolant sensor is located, I am "seeing" that the level of the coolant may be near the level of the sensor.

Then pulled off the overflow cap, I do not see a tube that SHOULD? connect and go toward the bottom of the tank. I would assume there should be, so that when the engine cools, it draws the coolant back in.
Can someone verify if there is to be a tube connected to the overflow tank cap that protrudes into the tank?

Is there an online schematic of the radiator front end?

Thank you for your help.

Thanks for the reply...yet there is ample evidence that my thermostat is working properly. The motor gets up to temp and holds around the 160 mark.

I have discovered for sure there is a tube that protrudes from the overflow cap. And I believe the reason the coolant level remains at a lower than normal level is because of the missing tube in the overflow tank. When the system heats up, it expands into the overflow tank, and is unable to return because of the missing tube. Therefore, the coolant level will always have a new normal level as it will no longer be at a level to get pushed out into the overflow tank.

So this should explain why I only see the (problem) temp rise when the outdoor temp is warmer in combination with the low coolant level.

I was able to get to the dealership to verify the missing part, and purchased the correct tube.

Yes there is supposed to be a tube on there. It is also marked with a line to show the proper level...busmech...1998 GTP box stock...