1995 pontiac grand am overheating. new radiator, thermostat. mechanic says air in system. any ideas?

The system could be air locked like your mechanic says, a waterpump is meant to pump water, not air. So if there is an air bubble it will make it as far as your waterpump. It can be a pain to get the air out, I have sometimes left the rad cap loose and let the engine run for a while and eventually the air would make it out but you will likely have hot coolant splash out with the air so watch it from a distance. Does the car have good heat from the heater at all times or does it drop off when the engine is overheating, if it does then you know the coolant is not circulating. Is your electric fan kicking in when it's supposed to.

I have seen waterpumps that the fins busted off from having a bit of ice flowing through the system... not sure how cold it is where you are or the percentage of your coolant but that could be a reason why reving the engine would make a difference.

If your head gasket is bad it could be pushing combustion air into the coolant but coolant will normally push coolant back into the cylinder after the engine is shut off causing a the car to run bad when started with a minor leak and not Even turn over with a bad leak.

Try a different mechanic...he may be good, but might have his mind made up and overlooking a different problem.

One thing you left out. What were you doing when this started? From the way you explain it, it just started doing this on its own. What made the coolant get low to begin with?

You can bleed your system by making the radiator the highest point. An air bubble will settle to the highest point, or to a relief valve that is on the engine somewhere around the thermostat housing. Some systems must be bled through this valve or you can't get the air out. Jack the front up until the radiator cap is higher than the engine, and try bleeding it that way. I also suspect the fins that pumps the coolant has came off the pump, and/or slipping on the shaft. It would do just what its doing right now if it did. Once the thermostat has opened you should be able to look into the radiator, and see the coolant flowing out of the tubes. You may have to run the engine until the bottom gets hot too with the radiator cap off. This is also a sign of a plugged up radiator. Try running it with the cap off until it is pushing coolant out of the top, tighten the cap, and let the engine cool over night. The next morning remove the cap and fill with coolant to the top. Replace the cap, and run it till it opens the thermostat. Now see if the bottom hose is getting hot, if not then have the radiator cleaned or replaced. An air bubble should work its way to the top over night.

Glad to help you, Good Luck!!!

Grand Am 1995

You've got two bleeders.One for each radiator hose.Make sure engine is cold.Open each bleeder and crank car.As water starts coming out of each one shut the bleeder off.Make sure you have plenty of water in radiator and jug before starting.I had a 95 monte carlo with tha same problem.Thought I could fix it while hot.WRONG.The bleeders are easy to find.About 8 to ten inches back from thermostat on one side.Other side close to waterpump.Car needs to be cold.Hope this helps.

Air in the system?! That seems silly. Sounds to me that you might have a clog in your radiator if there is a temperature difference like you stated. Check your upper and lower hoses and make sure that you don't see any leaks and your coolant level is above the core. Ensure that your water pump is working too just to cover all the basics. I'd still say radiator clog.

Sounds like air to me too. Look on block for a bolt 3/4 way up or find a service manual showing how to bleed system