Draper Expert Radiator and Cap Pressure Test Kit (32 Piece)

The Draper Expert RPT2 Radiator and Cap Pressure Test Kit is a professional thirty-two piece cooling system diagnostic kit designed for pressure testing both the cooling system and radiator caps on most popular vehicles. Building on the foundation of a standard pressure test kit, the RPT2 goes further — providing 30 colour coded adaptors covering both direct radiator and expansion tank connections and a dedicated range of radiator cap testing adaptors, alongside a hand pump with a gauge graduated in both bar and PSI for accurate, clearly readable pressure monitoring across both measurement systems.

The colour coded adaptor system makes vehicle-to-adaptor identification fast and reliable in a busy workshop environment, while the quick coupling system and pressure release pin ensure safe, efficient operation across back-to-back testing procedures. Supplied in a carrying case with display sleeve, the RPT2 is the most comprehensive cooling system pressure test kit in the Draper Expert range — and the definitive choice for workshops that need complete radiator and cap testing capability in a single, well-organised kit.

What's in the Kit?

The RPT2 contains thirty-two pieces providing full cooling system and radiator cap pressure testing coverage:

Hand Pump with Bar/PSI Gauge and Quick Coupling System: The central tool of the RPT2, the hand pump delivers simple, controlled pressurisation of the cooling system or radiator cap to the required test pressure. The integrated gauge is graduated in both bar and PSI — providing clear, accurate pressure readings in whichever measurement unit the technician prefers or the vehicle's cap rating specifies. The quick coupling system allows the full range of thirty adaptors to be interchanged rapidly and tool-free, while the pressure release pin ensures safe depressurisation before adaptor detachment — preventing pressurised coolant release at all times.

Cooling System Adaptors x20 — Direct Radiator and Expansion Tank Connection: Twenty colour coded adaptors provide pressure-tight direct connection to the radiator filler neck or expansion tank cap opening across the broadest possible range of popular vehicle cooling system configurations. The colour coding allows the correct adaptor to be quickly identified and retrieved from the case, reducing vehicle-to-vehicle changeover time and eliminating the trial-and-error approach often required with uncoded adaptor sets. Each adaptor is profiled to seal correctly against its specific filler neck geometry, ensuring an accurate pressure test result without adaptor leakage producing a false reading.

Radiator Cap Testing Adaptors x10 — Direct Cap Pressure Testing: Ten dedicated radiator cap testing adaptors extend the RPT2's capability beyond the cooling system itself to include direct pressure testing of the radiator or expansion tank cap. The cap is the cooling system's primary pressure relief valve — if it fails to hold the specified pressure, the system will lose coolant prematurely through the overflow, leading to unexplained coolant loss without any leak in the system itself. The ten cap testing adaptors cover the range of cap designs found across popular vehicles, allowing the cap to be tested directly on the hand pump before being returned to service or replaced.

Carrying Case with Display Sleeve: All thirty-two pieces are supplied in a carrying case with display sleeve, keeping the complete adaptor range organised by colour code and type, protecting the pump and gauge between uses and ensuring the full kit is always together and immediately accessible for the next job.

Key Features

• Thirty-two piece cooling system and radiator cap pressure test kit for most popular vehicles
• Thirty colour coded adaptors for fast, reliable vehicle-to-adaptor identification in a busy workshop
• Twenty cooling system adaptors for direct radiator and expansion tank connection
• Ten radiator cap testing adaptors for direct cap pressure testing across a wide range of cap designs
• Hand pump with gauge graduated in both bar and PSI for accurate, dual-unit pressure monitoring
• Quick coupling system for fast, tool-free adaptor changes between vehicles and test types
• Pressure release pin for safe system depressurisation before adaptor removal
• Diagnoses cooling system leaks and faulty pressure caps — the two most common causes of unexplained coolant loss
• Supplied in carrying case with display sleeve for organised, protected workshop storage
• Manufactured to Draper Expert's professional quality standards

How the RPT2 Differs from the RPT1

The RPT1 (22-piece) provides twenty cooling system adaptors and a hand pump for cooling system pressure testing — covering the core diagnostic requirement for most cooling system leak investigations. The RPT2 extends this capability in two important ways.

First, the RPT2 increases the adaptor count from twenty to thirty, providing ten additional cooling system adaptors that extend coverage across a broader range of vehicle applications — particularly useful for workshops servicing a wide variety of makes and model years where the RPT1's adaptor range may occasionally fall short.

Second and most significantly, the RPT2 adds ten dedicated radiator cap testing adaptors — a capability entirely absent from the RPT1. This is the defining upgrade between the two kits. A faulty radiator cap is one of the most common and most frequently overlooked causes of unexplained coolant loss, overheating and cooling system pressurisation issues. Without the ability to test the cap directly, a cap failure can easily be missed during a cooling system pressure test — leading to an incorrect diagnosis and unnecessary further investigation or repair.

The RPT2's cap testing capability closes this diagnostic gap completely, allowing the cap to be tested in seconds and either confirmed as serviceable or identified as the cause of the problem — saving both diagnostic time and customer frustration.

The gauge's dual bar/PSI graduation is a further practical improvement over single-unit gauges, allowing the applied pressure to be read directly in whichever unit the vehicle's cap is rated in without conversion.

Why Choose the Draper Expert RPT2?

Unexplained coolant loss is one of the most common and diagnostically challenging presentations in the independent workshop. The causes range from visible external leaks at hose joints, the radiator and water pump, through to invisible internal losses at the head gasket — but one of the most frequently overlooked causes sits right on top of the radiator or expansion tank: a faulty pressure cap.

The radiator cap is a precision pressure relief valve. When it fails to hold its rated pressure, the cooling system cannot maintain the elevated boiling point that the pressurised system is designed to provide — leading to premature coolant boil-off through the overflow, apparent coolant loss with no visible leak, and a tendency to overheat in conditions that a correctly sealed system would handle without difficulty. A cap that tests below its rated pressure may appear visually perfect and show no obvious signs of failure — making pressure testing the only reliable way to identify this fault.

The RPT2's ten cap testing adaptors make this test a routine thirty-second addition to any cooling system diagnosis — transforming it from a capability that requires a specialist tool into a standard step in the diagnostic process. Combined with the twenty cooling system adaptors for direct system pressure testing, the RPT2 provides the complete diagnostic picture: confirming whether the leak is in the system, in the cap, or both — on the first visit, without uncertainty.

The colour coded adaptor system reflects the practical reality of a busy workshop where speed matters — allowing the correct adaptor to be identified and fitted immediately rather than working through an uncoded set one by one.

The Draper Expert range is trusted throughout the UK professional workshop trade for precision engineering, robust build quality and genuine value.

Ideal Applications

The RPT2 provides complete cooling system and cap pressure testing capability for a wide range of diagnostic and inspection scenarios, including:

• Unexplained coolant loss diagnosis — testing both the system and the cap to identify the source of coolant loss comprehensively in a single diagnostic session
• Faulty radiator cap identification — directly testing cap pressure relief performance to confirm whether the cap is holding its rated pressure or requires replacement
• Cooling system leak detection — locating external leaks at hoses, the radiator, water pump, heater matrix and expansion tank under test pressure
• Head gasket integrity checking — identifying internal coolant loss where no external leak or cap fault is found, indicating potential head gasket failure
• Post-repair cooling system verification — confirming pressure-tight cooling system and correct cap performance following radiator, hose, head gasket or water pump repair
• Pre-purchase vehicle inspection — comprehensive cooling system health check covering both system integrity and cap performance as part of a pre-sale inspection

Frequently Asked Questions

Q: What is the difference between the RPT1 and RPT2? The RPT2 extends the RPT1's capability by adding ten dedicated radiator cap testing adaptors — allowing direct cap pressure testing in addition to cooling system pressure testing. The RPT2 also increases the total cooling system adaptor count and features a gauge graduated in both bar and PSI rather than a single unit. For workshops that need complete cooling system and cap testing capability, the RPT2 is the definitive choice.

Q: Why is radiator cap testing important? The radiator cap is the cooling system's pressure relief valve. A cap that fails to hold its rated pressure causes the system to lose coolant prematurely through the overflow, leading to apparent coolant loss with no visible leak and a tendency to overheat. Cap failure is one of the most common and most easily missed causes of unexplained coolant loss — direct cap pressure testing with the RPT2 identifies this fault quickly and definitively.

Q: How many adaptors are included in the RPT2? The RPT2 includes thirty colour coded adaptors in total — twenty for direct radiator and expansion tank connection for cooling system pressure testing, and ten for direct radiator cap pressure testing. Combined with the hand pump with gauge and carrying case, the complete kit is thirty-two pieces.

Q: Why are the adaptors colour coded? Colour coding allows the correct adaptor for a specific vehicle or cap type to be quickly identified and retrieved from the case without working through an uncoded set one by one. In a busy workshop where multiple vehicles are being tested, colour coding significantly reduces changeover time and the risk of selecting an incorrect adaptor.

Q: What pressure units does the RPT2 gauge display? The RPT2's integrated gauge is graduated in both bar and PSI, allowing pressure to be read directly in whichever unit the vehicle's radiator cap is rated in — without the need for unit conversion.

Q: Is the pressure release pin important to use before removing the adaptor? Yes — always. The pressure release pin safely depressurises the cooling system before the adaptor is detached. Removing the adaptor without depressurising first will release pressurised hot coolant, which can cause burns and contamination. Always depressurise using the release pin before detachment.

Q: Is the RPT2 supplied with a storage case? Yes. The complete thirty-two piece RPT2 kit is supplied in a carrying case with display sleeve, keeping all adaptors organised by colour code and type, and protecting the pump and gauge between uses.