Thanks. All of this started after the shop changed plugs and wires and distributor, and had water pump off so replaced gasket. I can’t help but wonder if it’s somehow related to that work they did. But when I removed the battery there was that little puddle of coolant, which led me down the path of replacing the reservoir tank... ugh.... it’s frustrating tracking down these gremlins!

 

Sucks I haven't been on here lately and didn't respond sooner. After reading your original post, my first thought was to tell you to check under the battery tray for a leak. It's pretty common on these and tricky to spot it actually leaking. Surprise Craby didn't make that suggestion right off the bat.The other suggestion I would have had was to check plugs individually and see if one is abnormally clean. That would indicate coolant being burned in the cylinder, which has a nice steam clean effect.

Just an FYI, my reservoir cap doesn't fit tight and have zero issues with pulling coolant. I've also ran into an issue where I had to constantly add coolant to the radiator after having the system open. There can still be air pockets in the system. Like Crabs said, these can be a ***** to bleed.

 

Thanks. I love these forums because everyone is so helpful! My shop did a pressure test and found a hose leaking- can’t recall which one and don’t have the paperwork in front of me- it’s a long, twisted one that they said “gm likes” to the tune of $250! I’m relieved to know my overflow tank cap doesn’t have to fit perfectly- but I was thinking (uh oh) there must be a way to rethread the bottle? The caps are fine.