Oil in spark plug well, car won't start
Oil pooled around a spark plug does more than make a mess. It can short the ignition path and leave you with an engine that cranks but will not fire. When a no-start appears together with wet spark plug tubes, the likely culprit is a failed seal or cover gasket allowing engine oil into an area that must stay dry. The condition degrades ignition performance and may also point to aging valve cover or tube seals. Understanding how the leak affects spark delivery helps you focus the diagnosis and avoid swapping parts blindly.
Direct answer
Oil in a spark plug well can prevent a car from starting because the liquid creates an alternate route for high-voltage electricity. Instead of the spark jumping across the electrode gap inside the cylinder, current may track along the oil film to the metal cylinder head. This robs the plug of a strong, consistent spark and makes the air-fuel mixture fail to ignite reliably during cranking.
The usual source of the oil is not the combustion chamber. A leaking valve cover gasket or a hardened spark plug tube seal lets crankcase oil seep down into the recess around the plug. The fix generally involves removing the oil, replacing the spark plugs if they are fouled, and installing fresh sealing components. Confirm the exact gasket and seal design for your engine because layouts differ between overhead-cam and pushrod designs.