Here's a breakdown of possible causes and troubleshooting steps:
Possible Causes:
* Head Gasket Failure: This is a common issue in older vehicles and can cause coolant to leak into the cylinders, resulting in white smoke from the exhaust and potential overheating. The engine might also lose compression.
* Cracked Cylinder Head: Similar to a head gasket failure, a crack in the cylinder head can allow coolant to enter the cylinders.
* Blown Head: A severe case where the head is actually damaged and needs replacement.
* Oil Consumption: If you're burning oil, it might be due to worn piston rings, valve stem seals, or other internal engine wear. This would result in blueish smoke from the exhaust.
* Coolant Leak (Unrelated to the Water Pump): The problem might be a leak elsewhere in the cooling system (hose, radiator, etc.) that you didn't notice before.
* Incorrect Belt Routing: While unlikely if you followed a diagram, an incorrectly routed serpentine belt could cause some components to not function properly, potentially leading to overheating or other issues.
* Damaged Components During Water Pump Replacement: It's possible you accidentally damaged something during the repair process. Double-check all components related to the water pump (hoses, thermostat, etc.).
Troubleshooting Steps:
1. Check for Smoke: Carefully observe the color of the smoke coming from the exhaust. White smoke often indicates coolant burning, while blue smoke usually means oil. Black smoke often points towards a rich fuel mixture, but that's less likely given your description.
2. Check Coolant Level: Check your coolant reservoir. If the level is significantly low, there's a leak somewhere in the system.
3. Check Oil Level: Check your oil dipstick. If the level is low or the oil is milky (indicating coolant mixing with oil), this strongly suggests a head gasket or cylinder head problem.
4. Inspect the Engine Bay: Carefully inspect the engine bay for any signs of coolant leaks (wet spots, puddles, etc.).
5. Pressure Test the Cooling System: A professional mechanic can perform a pressure test to identify leaks within the cooling system more effectively.
6. Compression Test: A compression test will measure the compression in each cylinder. Low compression indicates problems with the rings, valves, or head gasket.
What to do NOW:
* Stop driving the car immediately. Continuing to drive with a potential head gasket failure or other serious internal engine problem can cause irreversible damage.
* Have a qualified mechanic diagnose the problem. Describing your symptoms to a mechanic will help them pinpoint the cause much more effectively than trying to diagnose it yourself. The cost of a proper diagnosis is far less than the cost of potentially making the problem worse by continuing to run the engine.
The water pump belt is unlikely the direct cause of your issue. The symptoms you describe strongly suggest a more serious internal engine problem requiring professional attention.
