98 Camaro overheating

My daughters 98 V6 Camaro is overheating mainly at highway speeds.It seems to run cooler when just driving around town.I have already replaced the radiator with a brand new one and I put in a 180 degree thermostat.I also blasted the condensor really good with a garden hose when I had the radiator out to make sure it was getting good air flow.I know the cooling fans are good because I jumped them directly to the battery and they both blew strong and they were also working when hooked up to the cars wiring.The water pump is also only a few months old so I think it is ok.I also made sure and bled the air out of the cooling system when I put in the new radiator.So anyway I am stumped does anyone have any suggestions for me to try?Thanks in advance,Dave

Try this site: http://www.aa1car.com/library/overheat.htm

driving around town the motor is not on "load" so it will stay much cooler. is there no leaks? check hoses, levels and what not you ruled out your basics water pump, therm. only thing i can see is that there is a leak that is dropping your pressure causing your glycol to boil. also running premium fuel keeps temps down but its much more id say check for a wet hose seems like a leak.

hi dave, you got everything good, even to bleed the thermostat. but you might want to check the cap. has it overheated prior to the things you replaced????? sometimes the radiator cap after a couple of overheating incidents the cap might warp, causing for the water to evaporate at high temps. and pressure making it look it has a leak somewhere. thats the only thing I can think of. good luck!!!

1. if sytem flush dont do it


its the water pump, the dexcool eats them alive $30 and 1 hour to swap out

don't rule out bad intake gaskets. symptoms are very close.

if the intake gaskets are bad you will also notice a loss of coolant and coolant in the oil

not necessarily. depends on what area o the gasket is broken.

not necessarily. depends on what area o the gasket is broken.if the lower intake gasket goes on a 3.8 3800 camaro the only place it can go is into the oil,

the upper intake has an o ring and if it leaks it will flow out the from the front of the upper intake (never seen this leak before)

the leak you have never seen has happened to me before.

I only speak from experience. I'm not saying that it's definitely the problem, I'm only offering it as a suggestion and to not rule it out.

need more info....... is the car losing fluid...what do you mean by overheating...... pegging the guage or just runing hotter than it used to?

How old is the sensor to the water pump??

Let me see....process of eliminaton.....

1. Do a pressure test and let it set overnight....Leak or No leak...that is the question.

2. Check for exhaust gases in the coolant. No beans for that motor !!!

3. Maybe pull the plugs and check for any unusually fouling.

Waterpump ...Good, No air in system. 50/50 mix coolant to H20.

Back to the orignial post...."over heats mainly at Highway speeds" ...OK...How much hotter...than in town ???....

Isn't that car/motor set up for a 195 deg F thermostate???

Cheers, Dr. JJ