Our Products

Thermostats and Housings


In today’s high performance vehicle engines the Thermostat controls the temperature of the engine and therefore protecting it from the operating temperature created by the internal combustion and so the thermostat itself does not add to the temperature of the engine, it prevents overheating which would lead to engine damage and to the cooling system.

All engines must perform and run at a specified temperature and if an engine runs cold, ie without a thermostat, its fuel consumption will increase by 10-20% depending on the load and the engine will in fact not function correctly.

Motor Vehicles should never be run without a thermostat, regardless of the climatic conditions, as engines are manufactured to run at a certain temperature and maintain it through the performance of the cooling system, which brings the engine to its working temperature and maintains it, in order to prevent overheating and damage. It is also crucial that the correct pressure cap is also used to match the thermostat in use.

Overheating can result for a number of reasons including :

  • Non-Ironised water in the Cooling System.
  • Incorrect or Faulty Pressure Cap.
  • Poor quality Coolant or Incorrect Mixture.
  • Leaking or dirty Radiator
  • Defective Water Pump
  • Leaking Hoses
  • Faulty Thermo Switch or Sensor
  • Overloaded Vehicle.

Cold Weather Performance

  • In Older Vehicles – Ensure that the Heat Control is set to the correct temperature
  • Control correct Anti-freeze levels are maintained.
  • Check for split Hoses and radiator is not Clogged.
  • In older vehicles change the Thermostat to a higher temperature.
  • Ensure that the Thermostat is not stuck on open.

Water Outlets


The use of high specification plastics and injection mouldings is now at the forefront of vehicle design and modern cooling systems are no exception.

Plastics are far more cost effective to design and produce and generally offer unlimited scope to designers where engine compartment space is at a premium.

In many instances poor maintenance habits and the failure of associated components in the cooling system can quite often lead to secondary failure of the plastic water outlets and which then also need to be replaced.

These parts have for some time been an important part of the development of cooling systems and for this reason HpAp Industries places considerable emphasis on expanding its range of products in order to meet OEM specifications and market demands.

Complimentary Range of Pressure and Filler Caps


One of the simplest but key components in maintaining the correct running and optimum cooling in any engine is the Radiator Pressure Cap used to seal the radiator and this has become an important complimentary range of products also now available for most European and Japanese applications.

With greater levels of performance in today’s vehicles there is a need for cooling systems to work efficiently within a specified temperature range, normally between 85-96C (185-205F) and when the pressure in the cooling system increases above its psi rating, then the pressure cap releases some of the coolant into the expansion reservoir.

This radiator expansion reservoir or overflow tank is now common in most modern vehicles, where it collects the expanding coolant that is heated by the engine and recycles it back into the coolant system, once it loses sufficient heat. This overflow tank works in conjunction with the radiator cap to protect the engine and prevent coolant loss due to overflow.

The performance of the radiator cap is therefore crucial to keeping the psi of your cooling system at a higher level so that the coolant can absorb more heat from the engine and in the event of overheating issues, then the simple replacement of the radiator cap can be a quick and cost effective fix for coolant pressure problems.

Temperature Sensors & Senders


Linked with our extensive range of Thermostat Housings we also offer as a separate range – Sensors and Temperature Senders which are manufactured to the highest specifications and standards to ensure the working life of the Housings and thermostats.

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