* Intake Manifold Gasket: This is a very common failure point on older GM vehicles, including the 1994 Blazer. The intake manifold gasket sits between the intake manifold and the engine block. A leak here can allow coolant to seep down and appear to be coming from near the oil pan. This is a relatively involved repair.
* Cylinder Head Gasket: This is a more serious issue. A blown head gasket can allow coolant to mix with oil (resulting in milky oil) or leak externally, often showing up in various places, including near the oil pan. This is a major repair.
* Water Pump: While typically more obvious as a leak from the front of the engine, a severe crack or leak at the base of the water pump *could* drip down to the area near the oil pan.
* Oil Cooler Lines (if equipped): Some engines had oil coolers integrated with the oil filter. A leak in these lines could leak coolant if the lines also carry coolant. This is less common but possible.
What you need to do:
1. Don't drive the vehicle until the leak is diagnosed and repaired. Driving with a coolant leak can lead to overheating, engine damage, and potentially a catastrophic engine failure.
2. Thorough visual inspection: Once the engine is cool, carefully inspect the area behind the engine, focusing on the intake manifold, the cylinder head, and the water pump. Look for obvious signs of coolant stains, dripping, or corrosion. A mechanic's mirror might help with visibility.
3. Pressure test the cooling system: A mechanic can pressure test the cooling system to pinpoint the exact location of the leak. This is crucial for accurate diagnosis.
4. Oil inspection: Check your engine oil. If it's milky or has a brownish color (instead of its normal amber), it strongly suggests a head gasket failure.
5. Professional repair: Given the location of the leak and the potential severity of the problem (head gasket, intake manifold gasket), it's highly recommended to take your Blazer to a qualified mechanic for diagnosis and repair. Attempting these repairs yourself without experience is strongly discouraged.
Ignoring this leak is risky. The sooner you get it diagnosed and repaired, the better the chances of avoiding costly engine damage.
