Frank, there definitely is a ball and spring assembly in most
oil cooler plates, but the spring would be smaller than the
oil pump check valve spring.... In any case, you may as well check it. If it's not too much trouble, you'll have to pull the
oil filter adaptor off, then the centre threaded section that this adaptor attaches to. From there you can get to the back of the sandwich plate. Hopefully, there's still a ball in there!
Now, when reinstalling everything, remember to attach your oil filter lines the right way
