Overhead cam engine timing chains may use mechanical, spring, or ___________ tensioners

• A. Electronic
• B. Manual
• C. Hydraulic
• D. Pneumatic

Answer: (C)

Overhead cam timing chains need a tensioner to keep the chain tight as it spins around the gears. A hydraulic tensioner uses engine oil pressure to apply and maintain that tension. Inside the tensioner, oil pressure pushes a piston or plunger against the chain, automatically adjusting as wear, temperature, and engine speed change. This self-regulating action helps keep the chain snug and reduces slack, which is why hydraulic tensioners are common in modern engines.

Electronic tensioners aren’t typical for timing chains, and manual tensioners require constant adjustment rather than self-adjusting operation. Pneumatic tensioners aren’t a standard option for this purpose either. The hydraulic type best fits how these systems are designed to maintain consistent tension automatically.