Expansion tank caps Radiator expansion tank cap for Land Rover Expansion tank sealing pressure cap OE MJA4440BA
Expansion tank caps Radiator expansion tank cap for Land Rover Expansion tank sealing pressure cap OE MJA4440BA
Product Description:
Coolant expansion tank cover
OE NO.: MJA4440BA PCD500030
Applicable vehicle type: For Land Rover
The coolant expansion tank cap serves as a critical sealing and pressure control component within the automotive cooling system, mounted atop the expansion tank (also termed the reservoir or coolant recovery tank). Through its integrated spring-loaded valve mechanism, it maintains stable internal pressure within the cooling system, prevents coolant boiling and leakage, and provides safe pressure relief during overpressurisation.
Installation Guidelines
- Clean the expansion tank opening to ensure no contaminants are present
- Align the threads, manually pre-tighten, then secure with a torque wrench to the specified torque (typically 12-20Nm)
- Verify the seal ring is correctly positioned without deformation or crushing
Fault Indicators
- Frequent coolant depletion: Inspect the cap seal integrity and pressure valve functionality
- Insufficient system pressure: May lead to boiling and overheating
- Failure to release excess pressure: May cause pipe rupture
Company Profile:
Beijing Huarui Jietong Trading Co., Ltd. brings 20 years of automotive aftermarket expertise as a professional auto parts supplier. With strategic locations in Beijing, Guangzhou, and Jiangsu, we efficiently meet quality and quantity demands for global customers.

The company primarily focuses on accessories for Land Rover, Jaguar, and VO LVO product series, including Air Conditioning Systems, Braking Systems, Driving Systems, Engine Systems, Cooling Systems, Auto Body Systems, Steering Systems, Suspension Systems, Transmission Systems, and other related parts. Facing the trend of economic globalization, our company is committed to bringing better products and services to the world, providing high-quality products and services for domestic and foreign enterprises and customers.
We welcome any inquiries and look forward to your contact.

- 20 years of specialized auto parts industry experience
- Expert technical team for comprehensive support
- Direct partnerships with repair shops for real-world feedback
- Premium quality parts ensuring reliability and durability
- Extensive inventory with over 500,000+ items ready to ship
- Responsive customer service with quick turnaround
- Customized solutions for specific vehicle requirements
- Professional technical guidance and installation support
- Comprehensive 12-month warranty coverage
- Competitive pricing through optimized supply chains
- Rigorous quality control meeting industry standards
- Efficient global shipping via multiple carriers
Items ship within 3-7 business days via Epacket/UPS/FEDEX/DHL/EMS.
Remote areas may incur additional shipping fees.
Inspect items upon delivery and contact us immediately for any damage.
Russian customers must provide full name; Brazilian customers must provide tax number for courier shipments.
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.







