Hi Nikki,
This is not uncommon for the gaskets that they provide to not fit quite right.
You have a couple options. Parts stores sell sheets of gasket material and you can make your own gasket. Or you can just get a silicone sealant which will probably be the best option and is what I usually use instead of the gasket. Just make sure you get one that is meant for coolant. Attached is a picture of a common one.
You just put a bead of this on the perimeter of the sealing surface and then install it and let it dry.
Let me know if you have questions.
Aug 30, 2019 at 1:11 PM