[TheBlueFlash]

A couple of weeks ago, I checked my coolant levels in my 2013 Volt. I guess maybe I put the cap back on without tightening it or something, because I opened the hood today to refill my washer fluid and noticed the coolant cap was gone. It is the coolant reservoir in the back on the passenger side. Attaching a photo for reference. I found the cap on gmpartsdirect for $7.97 so no worries there, but should I be concerned about contamination of the fluid in the system after driving without a cap for a few weeks? Do I need to get the system flushed asap? Levels look okay, so I didn't lose any from sloshing around.

 

[jayoldschool]

Just go to the dealer and get one today.

 

[Prohidium]

I wouldn't worry about it. Wait until your 5 year flush and fill as you are not too far away from it.

 

[Raymondjram]

The GM coolant reservoir isn't under pressure unless the gas engine is very hot and coolant begins to flow out from the radiator, so a missing cap isn't a big deal. BTW, most GM coolant reservoir caps are the same, and can be found at any auto shop.

 

[El Dobro]

You want cap #13502353 which is a 20lb. cap. There is another cap out there that looks just like it, but is a 15lb. cap.

 

[Upper5Percent]

WOW...you actually looked under your hood...