* Rod bearing failure: This is a very common cause of this type of failure. The connecting rods, which connect the pistons to the crankshaft, rely on bearings to allow smooth rotation. If these bearings fail (often due to insufficient lubrication or wear), the rod can start to knock against the crankshaft, causing a loud rattling sound. The resulting damage can quickly lead to low oil pressure as the oil passages are compromised.
* Crankshaft failure: Similar to rod bearing failure, a cracked or broken crankshaft will also cause a severe rattling and low oil pressure. The crankshaft is the central rotating component of the engine; its failure is devastating.
* Cam bearing failure: Although less common than rod bearing failure, camshaft bearings can also fail, causing rattling sounds and oil pressure loss. The camshaft operates the valves, and a failure here can cause significant internal damage.
* Oil pump failure: While less likely to cause the *initial* rattling, a failing oil pump will eventually lead to low oil pressure, potentially exacerbating existing damage and causing more noise as parts start rubbing together due to lack of lubrication.
* Major piston damage: A severely damaged or broken piston can also create a rattling noise and low oil pressure.
Why the sudden onset? The sudden nature of the event points to a catastrophic failure rather than a gradual wear-and-tear issue. This could be due to:
* Lack of oil maintenance: Improper oil changes, using the wrong oil, or not changing the oil filter frequently enough leads to engine wear and eventually catastrophic failure.
* Low oil level: Running the engine with low oil severely compromises lubrication, leading to accelerated wear and eventual failure.
* Pre-existing damage: Minor damage might have been present, leading to eventual catastrophic failure.
Important: Driving a vehicle with a rattling noise and low oil pressure is extremely dangerous and will likely cause irreparable damage to the engine. Stop driving immediately, have the vehicle towed, and avoid attempting to start it again until a mechanic has diagnosed the problem. Continuing to run the engine will likely lead to a complete engine seizure and require a costly rebuild or replacement.
