Test Equipment for Cooling Systems

Frequently Asked Questions About Cooling System Inspections

Inspecting a vehicle's cooling system can involve various steps: from pressure testing and leak detection to vacuum charging and checking the coolant. Here, we answer frequently asked questions about professional cooling system diagnostics in auto repair shops.

• What test equipment is needed to diagnose a vehicle's cooling system?

  The testing equipment required depends on the specific diagnostic task. A cooling system tester is used to pressurize the cooling system under controlled conditions in order to detect leaks. A radiator vacuum filler facilitates quick and largely air-bubble-free refilling. A CO₂ leak tester is used to check for combustion gases in the coolant. Refractometers and other measuring devices are used to check the antifreeze concentration and the condition of the coolant.

• How can you detect a leak in the cooling system?

  A commonly used method is a pressure test. To perform this test, a suitable test adapter is attached to the expansion tank or the radiator opening, and the system is pressurized using a cooling system tester. If the displayed pressure drops, there may be a leak. Next, check hoses, connections, the radiator, the expansion tank, the water pump, and the heat exchanger, among other components, for coolant leaks.
  
  The specified test pressure and the exact test procedure must comply with the vehicle manufacturer’s instructions.

• What is the difference between a pressure test and a vacuum test?

  During a pressure test, a controlled overpressure is generated in the cooling system. This allows for the detection of leaks, which become apparent through a drop in pressure or coolant leakage.
   

  During a vacuum test, a negative pressure is created in the cooling system. If the vacuum remains stable, the system can then be filled using a suitable device. The vacuum method ensures uniform filling and reduces the risk of air pockets.

• When should a cooling system be filled using a vacuum?

  Vacuum filling is particularly recommended after draining the coolant or after repairs in which large portions of the cooling system were drained. These include, for example, the replacement of the radiator, the water pump, coolant hoses, or components of the thermal management system.
  
  Before refilling, you can check whether the vacuum created is being maintained. This prevents a system with an obvious leak from being refilled with coolant immediately.

• Wie wird eine defekte Zylinderkopfdichtung über das Kühlsystem erkannt?

  A standard pressure test shows whether the cooling system is losing pressure, but it cannot always clearly determine the cause. If there is a suspicion that exhaust gases are entering the cooling system, a CO₂ leak tester for the cylinder head can also be used.

  This test checks whether combustion gases can be detected in the area of the coolant or the expansion tank. The result should always be evaluated in conjunction with other diagnostic data and the manufacturer’s specifications.

• How do I find the right cooling system adapter for a vehicle?

  The test adapter must fit the opening or connection point of the respective vehicle and reliably seal the cooling system. Depending on the vehicle, the adapter is attached to the expansion tank or directly to the radiator opening.

  Leitenberger Automotive Test Equipment offers vehicle-specific and universal cooling system test adapters. You can find the corresponding vehicle manufacturers and models in the adapter list in the service area. For hard-to-reach connections, adapters with an angled fitting or a connecting hose may be useful.

• Can the cooling systems of hybrid and electric vehicles also be tested?

  Hybrid and electric vehicles also have cooling and thermal management systems that must be checked for leaks and properly filled. Depending on the vehicle, there may be several separate systems for the battery, power electronics, electric motor, and cabin climate control.

  The inspection must be performed exclusively in accordance with the vehicle manufacturer’s specifications and in compliance with the requirements for working on high-voltage vehicles. Special filling and testing devices for the thermal management of electric vehicles are available for these applications.

• Why should the radiator cap also be checked?

  The radiator cap, or expansion tank cap, is part of the cooling system’s pressure regulation mechanism. A defective valve or damaged gasket can lead to coolant loss, incorrect system pressure, or engine cooling problems.
  
  Using a compatible cap test adapter allows the cap to be tested separately from the cooling system. This makes it possible to determine whether the cause of a pressure loss is possibly the cap itself rather than another system component.

• How is the condition of the coolant checked?

  In addition to leak testing, cooling system maintenance also includes checking the coolant. For example, a suitable refractometer can be used to assess the antifreeze content. Depending on the vehicle and coolant, conductivity, concentration, contaminants, or other chemical properties may also be relevant.

  Only coolants that have been approved by the respective vehicle manufacturer may be used or mixed.

• Which cooling system testing solution is right for my workshop?

  For occasional testing on individual vehicle makes, a cooling system tester with selected adapters may be sufficient. Multi-make repair shops often benefit from a cooling system test kit with several vehicle-specific adapters. Separate solutions are available for commercial vehicles, agricultural machinery, motorcycles, and hybrid and electric vehicles.

  When making a selection, you should consider your existing vehicle fleet, the required pressure range, adapter coverage, and the desired testing procedures.