03 Sable Overheat/Temp rise at idle
About two weeks ago my Sable overheated; I pullled over, let it cool, refilled the coolant, and slowly made it back home.
I took it to my mechanic who did a basic radiator flush. It ran fine the next day, but began to overheat again on the way home off of the expressway.
These are the things we have completed up to this point. Changed the radiator cap (slight leak), changed the thermostat, a complete radiator flush (removal and cleaning), looked at coolant for oil (did not see any), changed oil (looked oil for coolant/water did not see any).
The next day car drove fine until at one point the guage got about 80% to hot. I pulled over and turned it off to cool down. The following day it did not appear to overheat, but I see the H/C guage move up slightly (about 65%) at idle. I even ran it on the highway a few times yesterday without any issues other than it getting a bit hot at idle.
My questions are:
*Could the radiator flush have left some residual gunk (guy who did it said it was about 90% full of stuff) that may have blocked the coolant?
*Would it be worth changing the pump (I've heard of the blades going bad), even though we have not seen any leak from the pump?
*My worst case scenario is a cracked/blown gasket. Any way of having a pressure test done without it costing too much?
*Any other ideas what it might be before I get to the expensive repairs?