Adding Coolant

I'm trying to add coolant to my car but under the cap to the reservoir is another cap that I can't get off. It's almost like a plug. I can twist it with pliers but it won't come out and I keep breaking pieces off. Anyone know what this is and how I can get it off to add coolants?

Try it when th car is warm and pour some hot water over it to get the cap warm. It creates a vacuum when its cold after running. pressure when its warm will help you. then try again . I busted mine but managed to get the pieces together.

Welcome to AF ashleyG !!

That would be the inside of your cap that has broken.

Like Crystalion said try warming it up.

A screw driver might help pry it up after its warmed a little.

Mine broke the same way, made it a real pain to open up. You can get a new one at NAPA pretty cheap.