Honda Civic IV (1988–1991) – cooling system, water pumps, thermostats and radiator caps

The cooling system in the Honda Civic IV (1988–1991) plays a crucial role in maintaining optimal engine temperature, ensuring proper coolant circulation and protecting classic D-series and B-series engines from overheating. In this category, you will find essential cooling components for the Civic 4th generation, including water pumps, thermostats and radiator caps. All products come from trusted manufacturers known for reliability and perfect compatibility with classic Honda engines.

Water Pumps – Aisin and NPW Japan

The water pump is the heart of the cooling system, responsible for circulating coolant throughout the engine. In the Civic IV, the pump is driven by the timing belt, which means its condition directly affects both cooling performance and overall engine safety.

• Aisin – a top-tier Japanese manufacturer, widely used as OEM on many Honda engines. Renowned for outstanding durability and precise fitment.
• NPW (Nissan Pump Manufacturing Co., Ltd.) – a highly respected Japanese company specializing exclusively in water pumps. Established in 1965, NPW is known for precision engineering, high reliability and OEM-equivalent performance. NPW pumps are considered one of the best premium replacements for classic Honda models.

It is recommended to replace the water pump during every timing belt service or at the first signs of leakage from the inspection hole.

Thermostats – Honda OEM, Tama, Blueprint

The thermostat ensures rapid engine warm-up and stable operating temperature. A malfunctioning thermostat can cause temperature fluctuations, increased fuel consumption, poor engine performance or overheating during city driving. Available brands include:

• Honda OEM – factory-grade components offering maximum precision.
• Tama – a Japanese specialist known for durable, highly accurate thermostats.
• Blueprint – reliable aftermarket replacements with excellent fitment.

Radiator Caps – HKT

The radiator cap maintains proper system pressure and plays a significant role in preventing coolant loss and boiling. A worn cap can lead to overheating, poor coolant circulation and difficulties with system bleeding. HKT offers high-quality caps compatible with Honda Civic IV specifications.

Why Regular Cooling System Maintenance Matters

• Prevents overheating and thermal damage to engine components.
• Ensures stable combustion and proper lubrication.
• Improves engine performance and fuel efficiency.
• Essential for reliable operation of 30+ year-old classic vehicles.

This category includes core cooling components for the Honda Civic IV (1988–1991). The assortment is gradually expanding with additional compatible parts for this classic model.

FAQ – Honda Civic IV Cooling System

When should the water pump be replaced?
During every timing belt service or at the first signs of leakage.

What are the symptoms of a failing thermostat?
Temperature fluctuations, slow warm-up, weak performance, overheating in traffic.

Can a faulty radiator cap cause coolant loss?
Yes. A worn cap fails to maintain proper pressure, which may cause boiling and coolant overflow.

Which coolant should be used?
The recommended option is Honda Type 2 or any high-quality long-life coolant (LLC) compatible with Japanese engines.