My 1997 Dodge is over heating

I have a 1997 dodge that is overheating as soon as i get on the highway or turns on the A/C. If the car is idle,the car is fine. I changed the water pump, changes the thermostate and flushed the rediator. Nothing worked. What amazes me that it should be the opposite.
The car should cools down on the highway and overheat in traffic. I had a presssure test done and it was leaking some where, but the car hardly looses water. I don't know what to do.

It must be pressurizing somewhere. It has to be.

I had this same problem on my 97 Intrepid. There are two cooling fans. One of these fans has a two speed motor. The motor wasn't working on the high speed and would slowly overheat on the highway. Both motors appeared to be working when visually inspected and were eliminated as the problem but I was not aware one of them had a higher speed. Changing the fan motor fixed the problem. Unfortunatly, I toasted the engine and warped the heads from overheating. The fan motor was about $100. The top end was $2400. If the heads are warped, they need to be streached at a cost of about $700. They can't be milled because the cams will bind from warpage. Hope this helps

BleedDodge: what do you mean by pressurizing?. Thanks

Look for a collapsing lower radiator hose as you park the car and rev it to 3000 rpms. Look for belt slippage on the water pump at same rpms. Power wash the radiator/condensor using degreaser. Thoroughly clean out the cooling system with strong Cleaner and open drain block plugs for flushing out . Make sure radiator is sealed up on all four sides , and, limit the coolant to water ratio at 25% coolant / 75% water (water is far better than coolant).

As a temporary measure till you can remedy your overheating on the highway...id remove the engine thermostat ; but id work on getting it remedied asap.

Let us know,

Dave

check both of your fans, the fans on these vehicle's go out quite often, try and spin them with your hand, also these engines can trap a lot of air in the system some times it may take up to 30-45 minutes of bleeding the system to take all of the air out. also checked you radiator cap,