Coolant Gurgle coming from recovery bottle.

[c good]

Noticed a gurgling noise while stopped for fuel. It was after pulling a pretty long grade so the Envoy had been working a little harder than usual

I've driven the same grade dozens of times but rarely stop for fuel at the top so have never heard this before.

I checked the recovery bottle for bubbles, fearing it was maybe head gadget problem.

No air bubbles, just a little chugging of coolant going back into the recovery bottle.

My temp gauge read perfectly normal the whole time. 210 Degrees

I understand the recovery bottle is there for a reason, and it's possible this is completely normal. I've just never heard it before as I usually don't stop at the top of this grade. Coolant level is stable after cooling down.

Or...maybe the radiator cap is a little weak and not holding correct pressure? Thanks for any input.

 

[Mooseman]

Could have heat soaked after the hard pull and shutdown. Could also be the cap that's not holding pressure. I'd keep driving it and monitor.

 

[TJBaker57]

Or...maybe the radiator cap is a little weak and not holding correct pressure?

I had this exact issue myself Bought a cap from Napa. That leaked. Got a used original cap from the boneyard. That fixed it.

 

[Realism]

replace both your rad cap and your holding tank cap. If you arent leaking underneath it means the top of your system is drawing air, and usually its one of the two, but best to replace both at same time.

 

[Mooseman]

replace both your rad cap and your holding tank cap.

The overflow tank cap is not like on the full size. It's just a regular non-pressure cap. The tank holds no pressure and is just an overflow. However, there have been instances of leaking tanks that would drip however this isn't the problem here.

 

[budwich]

My temp gauge read perfectly normal the whole time. 210 Degrees

are you saying that was temperature during "climb" or that was the temp even once your stopped with KEY OFF ... and then with KEY ON / engine off... to get an "NEW" temperature reading?

My guess is that you don't actually know what the temperature was once your stopped your vehicle. The water temperature climbed to probably something like 220-230F because of no pumping and latent engine heat around the whole interior of the engine.

I would take this as somewhat normal as thermal dynamics is a "science" while "free air cooling" is an "art"...

 

[Mooseman]

And the dash gauge is usually not that accurate with lots of "filtering" by the PCM. Unless you're using an OBD reader or something to read the PID directly, the gauge is not the most accurate.

 

[c good]

The overflow tank cap is not like on the full size. It's just a regular non-pressure cap. The tank holds no pressure and is just an overflow. However, there have been instances of leaking tanks that would drip however this isn't the problem here.

Thanks everyone for the input. I ordered an original AC Delco radiator cap. After researching a little more I'm pretty sure the coolant is sneaking past the bottom O-Ring on the cap. I think it's original so it would not surprise me. The coolant level is stable so not losing anything. I think the cap is just not holding pressure or it's sneaking past the O-Ring. Will keep everyone posted on the results.