i have just completed a head gasket on my v6 camaro. it seems like it can idle forever in my driveway and not get to operating temp but once we get it on the highway it gets to 240 or so and i pull over before it gets worse. it seems like it happens more when the air is on.... it has a new thermostat, proper coolant mixture, and head gasket. when the air is on the serpantine belt with shift side to side on the idler pully and i can take it off with just my hands... i was wondering if i just need to replace the tensioner to get it to stop overheating or if its something other than that.

 

Give more info? Even though it is a 5 year old car, have you flushed the cooling system? Is it dexcool, or real coolant?

 

If that's a single belt set up and it's slipping, then, yes, that could be the problem. If there's not enough tension, then the water pump isn't turning fast enough to circulate the coolant through the engine and radiator. Also, did you burp the system when you filled it up? You could have an air pocket. Easiest way to remedy that is to park it on an incline, loosen the radiator cap and run it up to operating temp. This should force all of the air out of the system. Then you just top off the coolant and happy motoring

 

its a ninety six and i have flushed it about three times. once before the head went out a year ago, once after i finished the head to get the crud out and once recently with dex cool. i used prestone green coolant the other times

 

i bled it on my driveway which is really inclined. i realized that the heater core was the high point in the cooling system so i tried the incline right away. like i said though the belt does move side to side and is fairly easy to take off. the only thing that makes me doubt or at least not be sure about it being the tensioner is that the power steering works flawlessly and so does the alternator....... i am just kinda tired of dumping money into this thing...

 

nvm i think i just threw a rod. swwweeeeeeeeeeeettt! thanks anyways though

 

If you threw a rod, you'd know it. Either they turn loose and come out the bottom of the oil pan (if you're lucky) or the side of the block. It would have started hammering like hell if a rod came loose or even if you spun a rod bearing. What makes you think it threw a rod?

 

loud knocking in what i believe is in the lower half. it wasnt gradual. it was instant