Every now and then when I am driving my SVT around town with the AC on both my water temp gauge and oil temp gauge will shoot all the way up but with no warning lights. As soon as I shut the AC off, they go back down to normal. I'm pretty sure the fans are engaging and the coolant level is good (just had to fix a leak in the expansion tank). Anyone have any idea on what might be causing this? It is very random. I was able to drive for 4 hours with the AC on and no problems yet earlier this afternoon, the symptoms returned.