* Hoses: Inspect all coolant hoses, including the upper and lower radiator hoses, heater hoses, and any smaller hoses connected to the engine. Look for cracks, bulges, or loose clamps. These are common failure points.
* Water Pump: A failing water pump can leak coolant, often seeping from the weep hole (a small hole designed to indicate a failing seal). Look for a wet spot around the pump.
* Radiator Connections: Even with a new radiator, the connections can be the source of the leak. Check the clamps on the hoses where they connect to the radiator. Ensure they are tight and the hoses are properly seated. Look for leaks around the connections themselves.
* Thermostat Housing: The gasket on the thermostat housing can fail and leak coolant.
* Engine Block/Cylinder Head Gasket: This is a more serious issue. A leak here could be internal or external. Internal leaks might not be immediately visible and would often manifest as coolant loss without obvious external wetness. External leaks might be more evident near the head gasket area.
* Heater Core: A leak in the heater core will result in coolant inside the vehicle's cabin, or possibly a wet spot under the passenger side carpeting.
* Pressure Cap: While less likely, a faulty pressure cap could allow coolant to seep out slowly.
To Diagnose:
1. Visual Inspection: Carefully examine all the above areas for any signs of coolant leakage (wet spots, stains, or residue). A flashlight can be helpful.
2. Pressure Test: A pressure test of the cooling system can help pinpoint leaks that aren't readily visible. This is best done by a mechanic.
3. Coolant Smell: A sweet smell of coolant might be present near the source of the leak.
4. Check Coolant Level: Regularly check your coolant level in the overflow tank. If it drops consistently, you have a leak.
If you're not comfortable performing these checks yourself, it's best to take your Pontiac Montana to a mechanic for a proper diagnosis and repair. Ignoring a coolant leak can lead to serious engine damage.
