Draper Diesel Compression Test Kit (12 Piece)

Reliable Diesel Compression Testing at a Practical Price

Worn piston rings, damaged valves, a failed head gasket — compression loss in a diesel engine rarely fixes itself and almost always gets worse if left undiagnosed. The Draper CTED2 gives you a fast, accurate way to identify which cylinders are underperforming, so the right repair can be carried out with confidence rather than guesswork.

Covering both direct injection and indirect injection diesel systems, the CTED2 is a capable and practical compression testing solution for independent garages, mobile mechanics and competent DIY enthusiasts who need professional-level results without the price tag of a top-tier kit.

High-Pressure Dual-Reading Gauge

The 63mm diameter gauge reads from 0–1000psi and 0–70bar simultaneously — a pressure range specifically suited to the high compression ratios characteristic of diesel engines, which commonly require readings well in excess of what a standard petrol compression tester can measure. The dual-scale face means you can read directly against whichever unit your service data uses without needing to carry out manual conversions.

The gauge is fitted with a heavy duty rubber protector that shields the precision instrument inside from knocks and drops during workshop use. It's a straightforward feature that makes a real difference to the long-term reliability of a tool that will be regularly in and out of a case.

Anti-Kink Hose for Consistent, Durable Performance

The 380mm flexible hose connects the gauge to the engine's glow plug bore and is protected by anti-kink coils at both ends. Hose failure in compression testers almost always begins at the connection points — where repeated bending, flexing and tension cause stress fractures over time. The anti-kink coils absorb and distribute this stress, significantly extending hose life and ensuring a consistent, leak-free seal throughout the tool's working life.

Accurate Readings, Safe Operation

Two integrated valve systems make the CTED2 both more accurate and safer to use. The Schrader one-way valve holds the peak pressure reading at the gauge between each compression stroke, preventing the needle from falling back and giving you a stable figure that accurately represents the cylinder's maximum compression. Once testing is complete, the spring-loaded pressure relief valve allows accumulated pressure to be safely bled off before the adaptor is removed — preventing the sudden release of high-pressure air that would otherwise occur when disconnecting from a pressurised bore.

Comprehensive 12-Piece Glow Plug Adaptor Set

The kit includes a well-selected set of glow plug dummy adaptors and fittings designed to cover a broad range of diesel engine specifications across cars, light commercial vehicles and agricultural machinery:

• 1 x 63mm diameter pressure gauge
• 1 x 380mm flexible hose
• 1 x Clamping bracket
• 1 x Right-angled hose adaptor
• 2 x Non-threaded dummy glow plugs
• 7 x Dummy glow plugs (various sizes)
• 1 x Assortment of sealing washers

The inclusion of both threaded and non-threaded dummy glow plugs broadens compatibility across engine types, while the right-angled hose adaptor is invaluable when glow plug access is restricted by adjacent engine components — a common occurrence on modern diesel engines with densely packaged engine bays. The assortment of sealing washers ensures a proper, leak-free fit across different adaptor and bore configurations.

Supplied in a Plastic Storage Case

All 12 components are housed in a plastic storage case that keeps adaptors, washers and fittings organised and protected between uses. With 12 separate pieces to manage, a dedicated case isn't just convenient — it's essential for ensuring the right adaptor is always to hand when you need it.

Key Features & Benefits

• Direct and indirect injection compatibility — Covers the two main diesel fuel system types found across cars, vans and light commercial vehicles
• 0–1000psi / 0–70bar dual reading gauge — High-pressure range suited to diesel compression ratios; dual scales eliminate unit conversion
• 63mm gauge face — Large and clear for accurate readings in all workshop conditions
• Heavy duty rubber gauge protector — Practical workshop durability for long-term reliability
• Anti-kink coils at both hose ends — Protects the hose at its most vulnerable points for extended service life
• Schrader one-way valve — Holds peak pressure for a stable, accurate compression reading
• Spring-loaded pressure relief valve — Safe, controlled pressure release after testing
• Right-angled hose adaptor — Provides access to restricted or obstructed glow plug locations
• Non-threaded and threaded glow plug dummies — Broader engine compatibility across diesel types
• Plastic storage case — All 12 pieces organised, protected and ready to use

Who Is It For?

The Draper CTED2 is well suited to independent workshops, mobile mechanics and experienced DIY enthusiasts who regularly work on diesel cars, light commercial vehicles and agricultural machinery and need a dependable, high-pressure compression tester without the extended adaptor range of a full master kit. It offers a strong balance of capability, build quality and value — covering the essential bases for diesel compression testing in a compact, well-organised 12-piece set.

For workshops requiring greater adaptor coverage across commercial vehicles, the Draper Expert CTED1-E offers an expanded 13-piece professional set. For workshops covering both petrol and diesel across motorcycles, cars and marine engines, the Draper Expert CTED2-E 42-piece master kit provides the most comprehensive solution.

Technical Specifications

• 12-piece diesel compression test kit for direct and indirect injection systems
• Dual-reading gauge 0–1000psi / 0–70bar — high-pressure range for diesel engines
• 63mm gauge face with heavy duty rubber protector for workshop durability
• 380mm flexible hose with anti-kink coils at both ends for long-term reliability
• Schrader one-way valve holds peak pressure; spring-loaded relief valve for safe pressure release
• Includes 7 threaded and 2 non-threaded dummy glow plugs for broad diesel compatibility
• Right-angled hose adaptor for restricted or obstructed glow plug access
• Assorted sealing washers for a leak-free fit across adaptor configurations
• All 12 pieces supplied in a fitted plastic storage case
• Product Code: CTED2 | Brand: Draper

Q: What diesel engine types is the CTED2 compatible with? The kit is compatible with both direct injection (DI) and indirect injection (IDI) diesel systems, covering the two principal diesel fuel system configurations found across modern and older diesel cars, light commercial vehicles and agricultural machinery.

Q: Why does this kit have a higher pressure range than petrol compression testers? Diesel engines operate at significantly higher compression ratios than petrol engines — typically between 14:1 and 25:1 — which produces much higher cylinder pressures. A 0–600psi petrol compression tester would be inadequate and potentially dangerous for diesel use. The CTED2's 0–1000psi/70bar range is specifically designed to accommodate the full compression pressure range of diesel engines safely and accurately.

Q: What is the difference between threaded and non-threaded glow plug adaptors? Threaded dummy glow plugs screw directly into the glow plug bore of the cylinder head, creating a secure, sealed connection for the compression hose. Non-threaded adaptors are designed for engines where the glow plug bore configuration requires a clamped or push-fit connection rather than a threaded one, broadening compatibility across different diesel engine designs.

Q: How does the Schrader valve improve accuracy? Without a one-way valve, cylinder pressure would fall back through the hose between each compression stroke, causing the gauge needle to fluctuate and making it difficult to read a stable peak figure. The Schrader valve retains the maximum pressure reached after each firing stroke, giving you a clear, stable reading that accurately represents the cylinder's peak compression.

Q: How do I safely release pressure after testing? The spring-loaded pressure relief valve allows built-up pressure to be bled off at the gauge in a controlled manner before you disconnect the hose from the engine. This is an important safety step — unscrewing an adaptor from a pressurised bore without first releasing pressure can cause a sudden, forceful release of compressed air.

Q: How does this compare to the Draper Expert CTED1-E? Both kits share the same 0–1000psi/70bar gauge range and core valve systems, and both cover direct and indirect injection diesel engines. The Expert CTED1-E is the professional-grade version with an expanded 13-piece adaptor set including additional glow plug dummies and adaptor sleeves for broader commercial vehicle coverage. The CTED2 offers the same core testing capability in a practical 12-piece set at a more accessible price point.