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Coolant leak when using the heater

My 01 Saturn SL2 with the DOHC 1.9 leaks coolant only in the winter when the heater is in use. I add coolant every 3 weeks or so when the dash light comes on. I do not need to add coolant over the summer. I can see coolant under the car after it sits and sometimes smell it burning right after shutting it off. Some coolant sits in a low spot on the front of the engine near the exhaust header but I can not tell exactly what or where the leak is.

Has anyone seen this before and what was the solution?

Is there a valve that controls coolant flow to the heater core? If so, one of the hoses to the core may be leaking, or one of the connections, and it only leaks during the winter because that’s when the valve is open and coolant is flowing. Otherwise I can’t explain the seasonal nature of the leak.

Such a valve, however, would likely be located behind the engine, and the hoses would run to the firewall. If there’s coolant on the front of the engine something in the area must be leaking.

I would try drying the visible coolant when the engine is cold, then starting it and letting it warm up while watching to see if the coolant puddle returns while the engine is running. Maybe you can see where it’s coming from.

Where does the coolant on the ground seem to be coming from? The front of the engine or the rear?

Thanks for the response. The coolant on the ground seems to be close to the middle of the engine but closer to the driver’s side front tire than the passenger’s. I will try your suggestion of watching it warm up to get a better idea of exactly where the leak is. I will also try to find out more about a possible valve and to check hoses behind the engine.