OTC Compression Tester Kit 5606 — Dual-Scale 2.5" Gauge, 5 Adapters & 2 Flexible Hoses in Case

The OTC 5606 Compression Tester Kit is a professional-grade dual-scale gauge set with multiple adapters and flexible hoses for fast, accurate gasoline engine compression checks.

This compact kit gathers everything a technician or serious DIYer needs to measure cylinder compression on cars, motorcycles, marine engines, and small engines. Built around a 2-1/2 inch dual-scale (0–300 psi / 0–2100 kPa) gauge, the set combines long and short flexible hoses, five thread adapters that fit flat and tapered plugs, and a rugged blow-molded case to keep parts organized and protected.

How does the OTC 5606 help diagnose engine performance?

The kit lets you quickly compare cylinder pressures to manufacturer specifications, revealing issues such as worn rings, leaking valves, or head gasket problems without disassembling the engine. With its dual-scale gauge and zero-adjust feature, readings are clear and repeatable.

• Dual-scale 2-1/2" gauge reads 0–300 psi and 0–2100 kPa for broad compatibility.
• Zero-adjust feature ensures accurate baseline before each test.
• Adapters fit both flat and tapered spark plug or injector seats for most gasoline engines.

What adapters and hoses are included, and why they matter?

The kit contains five thread adapters (10mm, 12mm, 14mm standard, 14mm long reach, and 18mm) plus two hose assemblies (12" flex and an extra-long 25" flex hose with quick coupler). This range covers domestic and import cars, motorcycles, marine units, and many small engines, so you can reach awkward spark plug locations.

• 12" and 25" flexible hoses let you access tight engine bays and long-reach plugs.
• Quick coupler on the 25" hose speeds connection and disconnection during testing.
• Adapters work on flat and tapered seats to reduce the need for adapters from other kits.

How durable and portable is the kit for shop or field use?

OTC designed this set for regular service use: nickel-plated fittings resist corrosion, the gauge has a protective rubber outer boot and chrome bezel, and all pieces stow in a blow-molded hard case with a removable lid. The case protects components and makes it easy to carry between jobs or store on a shelf.

• Corrosion-resistant nickel-plated metal parts for long service life.
• Protective gauge boot and chrome bezel reduce damage risk in busy shops.
• Blow-molded case keeps adapters, hoses, and replacement parts organized.

How do you get accurate readings in cluttered engine compartments?

The included 25" flex hose with a quick coupler positions the gauge where you can read it without awkward bending or obstructed views. The long hose plus a clear dual-scale dial improves safety and efficiency when diagnosing engines in confined or messy bays.

• 25" hose allows the gauge to sit outside crowded engine areas for easy reading.
• Quick coupler prevents pressure loss during connection and disconnection.
• Large 2-1/2" dial provides legible numbers and fast comparisons between cylinders.

Who this is for: The OTC 5606 is aimed at professional technicians, mobile mechanics, and committed DIY enthusiasts who need a portable, complete compression-testing solution for gasoline engines. It suits people who service a variety of vehicles and engines and want a reliable kit that reduces adapter hunting and speeds diagnostic work while protecting tools between jobs.