2001 Chevrolet Malibu

Engine Cooling problem
2001 Chevy Malibu 6 cyl Front Wheel Drive Automatic 150000 miles

I have a coolant leak that cannot be found by the shops that I have taken my car to. After driving for a period of time, I start to smell the coolant and once stopped I can see steam or smoke from what I presume to be the leaking coolant burning on the exhaust. I have already replaced the lower intake gasket (common problem I understand) around 85,000. The shops I took it to said they cannot find anything wrong. I only notice this leak in the winter months when I need to run the heater, but the mechanics assured me that there was not a leak in the heater core.

I am stumped and in need of suggestions. Thanks in advance.
March 27, 2009.

Did they check the water pump. Sometimes the can leak and not leak depending on the temp or how long its been running. I would start there.

Mar 27, 2009.