* Head Gasket Failure: This is the most common cause. A blown head gasket allows coolant to leak into the cylinders. The coolant turns to steam, creating the white smoke. The uneven pressure and the presence of coolant in the cylinders also cause the engine to shake.
* Cracked Cylinder Head: Similar to a blown head gasket, a crack in the cylinder head allows coolant to enter the combustion chamber. This will also produce white smoke and shaking.
* Cracked Engine Block: Less common but possible, a crack in the engine block can also lead to coolant leaking into the cylinders, producing the same symptoms.
* Coolant Leak into Intake Manifold: While not directly entering the cylinders, a leak into the intake manifold can draw coolant into the engine, resulting in white smoke and potentially rough running.
Less Likely, but Possible:
* Valve Stem Seals: While worn valve stem seals usually produce blue (oil) smoke, if they are particularly bad and mixed with coolant from another source (like a minor head gasket leak), it might contribute to a whitish hue.
* Excessive condensation (cold weather only): In very cold weather, condensation in the exhaust can produce temporary white smoke, but it usually clears quickly. The shaking would not be explained by this.
Diagnosing the Problem:
To determine the exact cause, a mechanic should:
* Inspect the coolant level: A low coolant level points towards a leak.
* Check for coolant in the oil: A milky, mayonnaise-like substance in the oil indicates coolant mixing with the oil, a clear sign of a head gasket or block crack.
* Pressure test the cooling system: This helps identify leaks in the system.
* Compression test the cylinders: Low compression in one or more cylinders points towards a head gasket failure, cracked head, or other internal engine damage.
* Visual inspection of the engine: Look for external coolant leaks.
Ignoring this problem will likely lead to significant engine damage. It's crucial to have a qualified mechanic diagnose and repair the issue promptly. Driving the truck with these symptoms risks catastrophic engine failure.
