Coolant does not flow through the intake manifold, nor would it cause an overheat. There is a passage through the throttle body that can plug and possibly cause an overheat, but it is somewhat rare. If you are not confident in who is giving you the diagnosis, and they have yet to do a block test, I would urge you to demand a test before spending anymore money. If they don't know how to perform the block test, or are not equipped, find someone who is. I would be willing to bet that it has leaking head gaskets(internal) due to pulled head bolt threads.
Wednesday, July 6th, 2011 AT 5:41 PM