Motorad T138 Engine Coolant Reservoir Cap

Engine Coolant Reservoir Cap Overview

The Motorad Standard T138 engine coolant reservoir cap is a threaded replacement cap built to meet OEM specifications. It is made from plastic and uses a round, black design with indicator markings for straightforward service checks.

Key Features

• Manufactured to OEM specifications for direct replacement use.
• Threaded female attachment for secure installation and removal.
• Standard open-system design with proper relief and vacuum valve function.
• Black plastic construction with indicator markings.
• Round profile with a 1.48 in. outside diameter.

Detailed Description

This Motorad coolant reservoir cap, part number T138, is engineered for vehicles that use a standard open cooling system cap with a threaded female connection. The cap is designed to seal the reservoir properly while supporting pressure control through relief and vacuum valves. Its compact 0.44 in. overall height and 0.33 in. cap depth help it match the original service profile. This part number T138 is a practical replacement for Nissan cooling system service, including applications on the Nissan Altima, Nissan Maxima, Nissan Quest, Nissan Frontier, and Nissan Xterra.

Motorad’s Standard line focuses on OE-style service parts that follow original specifications and are intended for straightforward replacement. This makes the T138 a suitable choice when you need a coolant reservoir cap that matches the original design and service function without unnecessary complexity. This part cross-references Gates (e.g., T138) for the same application.

What It Helps Address

• Loose or worn reservoir cap sealing.
• Loss of proper cooling system pressure control.
• Vacuum valve issues that affect coolant return.
• Cracked or damaged threaded cap threads.
• Service replacement for a missing or unreadable cap.

Installation Notes and Tips

Confirm the reservoir neck diameter, thread type, and system style before installation. This cap uses a female threaded attachment and is not vented or pressurized as a separate service feature. Match the cap to the reservoir opening and verify that the indicator markings are readable after installation.

Quality Assurance

Motorad states that this cap is quality tested and manufactured from high-quality components to meet OEM specifications. It is built to withstand demanding automotive cooling system conditions.