engine overheating

the most common problem with the alero and malibu w/3.4 engine is intake manifold gaskets are leaking. It will also have water in oil that can portray blown head gasket. 95% of the time it is only intake gasket leaking internally. Also look on top of bell housing for antifreeze.

Here is a guide to help

https://www.2carpros.com/articles/engine-overheating-or-running-hot

good luck!!

I had same problem; replaced the coolant temp sensor, thermostat, and reservoir cap. Didn't help. Turned out that the plastic reservoir itself was slightly warped/out-of-round where the cap screws in, so that even with cap on tightly it would not hold pressure. To test this, I put the black overflow hose that comes out of the reservoir (near the cap) into a clear plastic water bottle. With engine hot and a little water in the bottle, I could squeeze the radiator hose and see bubbles in the water bottle. No air or coolant is supposed to get through that cap until it's over 15PSI. Got a new reservoir ($35/RockAuto) and now system holds pressure... I'm leaving the plastic bottle in place, the overflow hose sort of holds it in place, doesn't interfere with nearby moving parts, and will show me if there's any more overflow (haven't seen any in 3 days)

I had this problem it has the head gaskets DOH!. Its normal for the temp gauge to run a little high on a 3.4

i had the same issue and it is normal for it to run a little hot because the gauge is off a little.