hello all, new guy here. My wife needs to smog her 2007 mazda 3i 2.0L her in California. She got it from her parents in Texas. Had the check engine light scanned and came up with thermostat stuck open. after removing the tensioner, i can clearly see what looks like part of the intake blocking half the top, drivers side bolt. i will try to attach a picture.

 

You can use an open ended wrench on it, but I guess the problem might be trying to get the bolt past that part of the intake., If that is the case, you will have to take off the intake manifold. It should not be too hard to take off as it is usually made of plastic these days and the stuff connecting to it is also pretty light. This would be a biger problem if it's being blocked by the exhaust manifold....

 

You do not need to remove the intake manifold. As the thermostat is moulded into the black plastic housing you can snap off the smaller of the two outlet pipes for more access.