2004 Dodge Stratus

2004 Dodge Stratus

My car has been losing engine coolant very quickly and I'm not sure why. I filled the reservoir before taking a 2 hr trip and by the end of the trip, the coolant was half gone. A mechanic told me that he did not find any leaks and that he didn't know what the problem was. He suggested getting a flush but I'm not sure if that will help. When the car is low on coolant, it usually overheats in stop-and-go traffic. What do you think I should do?
August 30, 2010.

Is there any evidence of coolant mixing with the engine oil? Also, is there white smoke coming from the exhaust?

There is no white smoke. What should I look for to determine if there is coolant mixing with engine oil?

Sep 1, 2010.
Pull the dipstick to see if there is a white creamy substance on it as well as the oil cap.

I did not find any white substances. Is there anything else you'd suggest?

Sep 9, 2010.
Have you checked the trans for any evidence of contamination?

Make sure you do not overfill the reservoir if you fill it above the level indicated it will just kick out the amount over the fill line.

Sep 26, 2010.
Hi: I haven't heard from you. I asked about the trans because the trans cooler is part of the radiator and if there is an internal problem, they can mix.

One last check I need you to do. With the engine cold, open the radiator cap and start the engine. Is there any pressure coming out or coolant being forced out?

Let me know.