Hello,
I hate to bump a dead thread, but I thought it would help future modders to know that this wasn't an isolated incident. Independently of OP's experience, I had a strikingly similar problem with my G37 and a Mishimoto sandwich plate adapter.
One of the mods on MyG37.com recommended I link the thread to here so readers can know that it wasn't a coincidence. I won't be buying Mishimoto again.
Ebay Oil Cooler - MyG37