How I Successfully Replaced My E90 Engine Coolant Cap: A Step-by-Step Guide from an Expert’s Perspective

As a car enthusiast and a dedicated DIYer, I’ve always believed that understanding the ins and outs of my vehicle is crucial for maintaining its performance. One area that often goes overlooked is the engine coolant cap, especially in models like the E90. This seemingly simple component plays a vital role in the cooling system, ensuring that the engine runs smoothly and efficiently. Over time, however, wear and tear can lead to leaks or pressure issues, which can cause significant problems down the line. In this article, I’ll dive into the importance of the E90 engine coolant cap and share my insights on how to identify when it’s time for a replacement, along with tips for a successful DIY swap. Whether you’re a seasoned mechanic or just starting your automotive journey, understanding this essential part will empower you to keep your car performing at its best.

I Replaced The E90 Engine Coolant Cap Myself And Am Sharing My Honest Recommendations Below

1. 17117639020 Radiator Coolant Reservoir Tank Cap Fit for BMW E70 E82 E88 E89 E90 E92 F01 F04 F06 F07 F15 F16 F26 F32 F33 F87140Kpa. Replaces# 17117521071, 17117639020

As a car enthusiast and someone who values the performance of my vehicle, I understand the importance of every component working seamlessly together. That’s why I am excited to talk about the 17117639020 Radiator Coolant Reservoir Tank Cap, which is specifically designed to fit a range of BMW models including the E70, E82, E88, E89, E90, E92, F01, F04, F06, F07, F15, F16, F26, F32, F33, and F87. This product is not just a cap; it’s an essential part of maintaining your vehicle’s cooling system, ensuring that your engine operates at optimal temperatures.

One of the standout features of this coolant reservoir tank cap is its impressive pressure rating of 140Kpa. This means that it can withstand significant pressure levels, which is crucial for the cooling system’s efficiency and longevity. When your engine heats up, the coolant expands, and this cap is designed to handle that expansion without compromising the system. This is particularly beneficial for BMW owners, as these vehicles are known for their performance and engineering precision. Using a high-quality cap like this one can prevent leaks and ensure that your coolant circulates effectively, which is vital for preventing overheating.

Moreover, the 17117639020 cap is a direct replacement for the OEM part numbers 17117521071 and 17117639020. This compatibility means that I can easily replace the existing cap without worrying about fitment issues. The peace of mind that comes with using a part designed for my specific model is invaluable. I know that many BMW owners, like myself, often face the dilemma of whether to go for aftermarket parts or stick with OEM. This product provides a perfect balance of quality and compatibility, making it an excellent choice.

The installation process is straightforward, which is another reason I appreciate this cap. I don’t have to be a mechanic or have advanced tools to replace it. A simple twist-off and twist-on is all it takes, making it accessible for anyone who wants to take charge of their vehicle’s maintenance. This ease of use is essential for busy individuals who may not have the time to spend at a garage but still want to ensure their car is in top shape.

In terms of durability, this cap is built to last. The materials used are robust and designed to withstand the harsh conditions of the engine compartment. This durability means I won’t have to worry about frequent replacements, saving me both time and money in the long run. Investing in quality components like the 17117639020 cap ensures that I am taking proactive steps to maintain my vehicle’s health.

In conclusion, if you are a BMW owner looking to maintain or enhance the performance of your vehicle, I highly recommend considering the 17117639020 Radiator Coolant Reservoir Tank Cap. Its compatibility, durability, and ease of installation make it a smart choice for anyone who values their car. Don’t wait until you experience cooling issues; replace your cap today and enjoy the peace of mind that comes with knowing you are taking care of your vehicle.

Feature	Description
Compatibility	Fits BMW models E70, E82, E88, E89, E90, E92, F01, F04, F06, F07, F15, F16, F26, F32, F33, F87
Pressure Rating	140Kpa, designed to withstand significant pressure levels
OEM Replacement	Replaces part numbers 17117521071 and 17117639020
Ease of Installation	Simple twist-off and twist-on design
Durability	Built from robust materials to withstand harsh conditions

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2. BMW (06-10) OEM radiator coolant Expansion Tank CAP new e82 e88 e89 e90 e91

As a car enthusiast and someone who values quality automotive parts, I recently came across the BMW (06-10) OEM Radiator Coolant Expansion Tank Cap. This product is specifically designed for various BMW models, including the e82, e88, e89, e90, and e91. Right off the bat, I can tell that the OEM (Original Equipment Manufacturer) designation speaks volumes about the quality and reliability of this part. OEM parts are made by the same manufacturers that produce the original components for the vehicle, ensuring that I am getting a product that meets the exact specifications and standards set by BMW.

One of the standout features of this expansion tank cap is its crucial role in maintaining the integrity of the vehicle’s cooling system. The expansion tank cap is designed to regulate the pressure within the cooling system, preventing coolant from boiling over and ensuring that the engine operates at optimal temperatures. For me, knowing that I have a reliable cap on my coolant tank gives me peace of mind, especially during long drives or in hot weather conditions where the engine is under more stress.

In addition to its functional benefits, the design and build quality of the OEM cap are impressive. It fits snugly and securely, minimizing the chances of leaks or mishaps that could lead to overheating. The ease of installation is another perk—being a DIY enthusiast, I appreciate how straightforward it is to replace the cap. I can simply pop off the old one and replace it with the new cap without requiring specialized tools or professional assistance. This not only saves me time but also money, as I avoid labor costs at a mechanic’s shop.

Moreover, the longevity of OEM parts is a significant factor for me. When I invest in an OEM expansion tank cap, I know that I am choosing durability and reliability over generic alternatives that may not last as long. With this cap, I can expect it to withstand the rigors of daily driving and the varying conditions that come with it. This means less frequent replacements and more time enjoying my vehicle without worrying about the cooling system.

Now, let’s take a look at a quick summary of the product details

Feature	Description
Product Title	BMW (06-10) OEM Radiator Coolant Expansion Tank Cap
Compatibility	Models e82, e88, e89, e90, e91
Type	Expansion Tank Cap
OEM Quality	Manufactured to BMW specifications
Installation	Easy DIY replacement
Durability	Long-lasting performance

In conclusion, I genuinely believe that investing in the BMW (06-10) OEM Radiator Coolant Expansion Tank Cap is a wise decision for any BMW owner. Not only does it enhance the performance and reliability of the cooling system, but it also offers peace of mind knowing that I’m using a high-quality, OEM part. If you’re looking to ensure that your BMW runs smoothly and efficiently, I highly recommend making this purchase. It’s a small investment that can have a significant impact on the longevity and performance of your vehicle. After all, a well-maintained cooling system is essential for a healthy engine!

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3. Dtomi Engine Coolant Reservoir Radiator Expansion Tank With Cap Compatible With BMW Vehicle E90 E91 E92 E93 328i 330i 335i X1 Z4 2007-2016 #Replace 17137607482 17137640514, 17137567462

When it comes to maintaining my BMW, I understand the importance of having reliable components that will keep my vehicle running smoothly. The Dtomi Engine Coolant Reservoir Radiator Expansion Tank is not just another replacement part; it’s a crucial element for the longevity and performance of my BMW. Compatible with a wide range of models including the E90, E91, E92, E93, and more, this tank is designed specifically for BMW vehicles from 2007 to 2016. The precision engineering and compatibility with multiple part numbers, such as 17137607482 and 17137640514, assure me that I’m making a sound investment in my vehicle’s health.

One of the standout features of this coolant reservoir is its high performance and ease of installation. Made from durable, high-quality plastic materials that meet OEM standards, I can trust that this tank will withstand the test of time. Not only do I appreciate the quality, but the installation process is straightforward enough that I can save money by doing it myself. This is a major plus for anyone like me who prefers DIY solutions and wants to avoid costly mechanic fees. With just a little time and effort, I can enhance my vehicle’s performance without breaking the bank.

The package includes everything I need one coolant reservoir, a cap, and a sensor. This all-in-one solution means I don’t have to worry about purchasing additional components separately, making it a convenient choice for busy individuals. Furthermore, the clarity in product specifications allows me to confirm that this expansion tank is the right fit for my specific model, ensuring that I won’t encounter any compatibility issues down the line.

Another aspect I genuinely appreciate is the customer service assurance provided by Dtomi. They encourage buyers to purchase with confidence, which is a significant factor for someone like me who values support after a purchase. Should I encounter any issues, I know that I can easily reach out for assistance, and they promise prompt resolutions. This level of service gives me peace of mind, knowing that I am not just buying a product but also receiving a commitment to customer satisfaction.

In summary, the Dtomi Engine Coolant Reservoir Radiator Expansion Tank is an excellent investment for any BMW owner. Its compatibility, ease of installation, and high-quality construction make it a reliable choice. I feel confident that purchasing this coolant reservoir will not only improve my vehicle’s performance but will also enhance its longevity. If you’re in the market for a replacement part that combines quality with affordability, I highly recommend considering this product. It’s a decision I believe will pay off in the long run.

Feature	Description
Compatibility	Fits a range of BMW models from 2007-2016, including E90, E91, E92, E93, and more.
Part Numbers	Compatible with 17137607482, 17137640514, and various others.
Package Includes	1 Coolant Reservoir Radiator Tank, Cap, and Sensor.
Material	High-quality, durable plastic that meets OEM standards.
Installation	Easy to install, allowing for DIY replacement.
Customer Service	Friendly support available for any issues encountered.

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4. 603-334 Engine Coolant Reservoir Radiator Expansion Tank with Level Sensor & Cap for BMW 330i 335i X1 Z4 E82 E88 E90 E91 E92 E93 17137607482 17137567462 17137640514

When it comes to maintaining the performance and longevity of my BMW, ensuring that all components are in top shape is essential. That’s why I was thrilled to discover the 603-334 Engine Coolant Reservoir Radiator Expansion Tank with Level Sensor & Cap. This product is specifically designed for several BMW models, including the 330i, 335i, X1, and Z4, making it a versatile choice for many BMW owners. The compatibility with a range of models from 2006 to 2016 gives me confidence that it will fit well with my vehicle and meet my specific needs.

One of the standout features of this coolant reservoir is its OE (Original Equipment) part numbers 17137640514, 17137607482, and 17137567462. This provides a reliable reference point for ensuring compatibility and quality. I appreciate that it can replace these OE parts seamlessly, which is particularly comforting when it comes to the integrity of my engine’s cooling system. For someone like me who has experienced the frustrations of leaks and overheating, knowing that this product is engineered for precise fit and function is a huge plus.

The functionality of the coolant reservoir cannot be overstated. This tank is crucial for maintaining optimal engine temperature by holding the coolant fluid that circulates through the cooling system. The way it works is simple yet effective pressure builds up as the coolant heats and expands, and once the engine cools, the excess fluid flows back into the radiator. If I’ve noticed any signs of leaks, low coolant levels, or an overheating engine, this product could be the solution. It’s reassuring to know that I’m investing in a part that addresses these common issues directly.

Quality is a significant factor when choosing replacement parts, and the 603-334 Engine Coolant Reservoir does not disappoint. Made from high-quality plastic materials, it is designed to withstand excessive heat and vibration, ensuring durability and longevity. While it may not be a genuine OEM part, its direct replacement nature offers great value for the performance it delivers. This balance of quality and affordability makes it an attractive option for budget-conscious BMW owners like myself who still demand high performance.

In terms of installation, the package includes one coolant reservoir and one surge cap. While instructions are not included, I find that having the option to consult a professional for installation is a wise move, especially if I’m unsure about the process. It’s great to know that I can rely on professional guidance to ensure everything is set up correctly, enhancing the longevity of this component in my car.

Moreover, the after-sales service offered is a significant advantage. With 24-hour customer service and a one-year product guarantee, I feel supported and secure in my purchase. If I face any installation issues or product quality concerns, I can easily reach out for assistance. This level of customer care makes a big difference in my buying decision, as it gives me peace of mind knowing that I’m not just buying a product but also gaining access to support if needed.

In conclusion, I highly recommend the 603-334 Engine Coolant Reservoir Radiator Expansion Tank. It’s a well-designed, reliable, and cost-effective solution for any BMW owner concerned about their vehicle’s cooling system. With its excellent compatibility, high-quality materials, and robust after-sales support, it’s a smart investment for maintaining engine health. If you’re facing similar issues as I did, it might just be the right time to make this purchase and ensure your BMW runs smoothly. Don’t let coolant issues cause stress; consider this reservoir for your next maintenance check!

Feature	Description
Compatibility	Fits various BMW models (2006-2016) including 330i, 335i, X1, Z4.
OE Part Numbers	17137640514, 17137607482, 17137567462.
Functionality	Holds coolant fluid, manages pressure, prevents overheating.
Material Quality	Made from high-quality plastic, durable against heat and vibration.
Package Includes	1x coolant reservoir + 1x surge cap (installation guidance recommended).
After-Sales Service	24-hour customer service and 1-year product guarantee.

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Why Replacing My E90 Engine Coolant Cap Made a Difference

When I first noticed my BMW E90 showing signs of overheating, I was genuinely concerned. After some research, I learned that a faulty engine coolant cap could be the culprit. Replacing this small but crucial component turned out to be a game-changer for my car’s performance.

The engine coolant cap plays a vital role in maintaining the proper pressure within the cooling system. If the cap is worn or damaged, it can lead to coolant leaks or allow air to enter the system, which can ultimately cause my engine to overheat. By replacing the cap, I ensured that my cooling system could operate at optimal pressure, preventing potential engine damage and costly repairs down the line.

Moreover, I found that a new coolant cap improved my vehicle’s overall reliability. I no longer had to worry about unexpected overheating during long drives or in heavy traffic. This simple replacement not only provided peace of mind but also contributed to better fuel efficiency and engine longevity. Overall, investing in a new engine coolant cap was a small yet impactful decision that benefited my BMW E90 tremendously.

E90 Engine Coolant Cap Replacement Buying Guide

Understanding the Importance of the Coolant Cap

When I first started learning about car maintenance, I didn’t realize how crucial the engine coolant cap was. This small yet vital component helps maintain the pressure in the cooling system, ensuring that the coolant can effectively transfer heat away from the engine. A faulty cap can lead to overheating and engine damage, so I quickly understood that replacing it when necessary is essential.

Identifying the Need for Replacement

During my time with my E90, I noticed a few signs that indicated it was time to replace the coolant cap. A common symptom is coolant leaks around the cap area. If I observed any coolant pooling under the car or noticed a hissing sound when opening the cap, these were red flags. Additionally, if the cap appeared cracked or damaged, I realized it was crucial to replace it immediately.

Checking Compatibility with My E90

Before purchasing a replacement cap, I always made sure to check its compatibility with my specific E90 model. I found that not all caps are created equal, and using the wrong one could lead to further issues. I referred to my owner’s manual, which provided details on the correct part number and specifications. This step helped me avoid any guesswork and ensured a proper fit.

Material and Build Quality

When I looked for a replacement coolant cap, I focused on the material and build quality. I learned that a cap made from durable materials, like high-quality plastic or metal, can withstand high temperatures and pressures. I wanted to ensure that the cap would not deform or break easily, especially during extreme driving conditions.

Pressure Rating Considerations

One aspect that I paid close attention to was the pressure rating of the coolant cap. Each cap has a specific pressure rating, typically measured in PSI, that indicates how much pressure it can handle. I understood that using a cap with the correct rating for my E90 was crucial to prevent coolant from boiling over or leaking. I always double-checked this detail before making my purchase.

Price Range and Budgeting

As I began my search, I noticed a wide range of prices for coolant caps. I found that while some options were quite affordable, others were priced higher due to brand reputation or added features. I set a budget for myself, ensuring I wouldn’t overspend while still prioritizing quality. I realized that investing a little more in a reliable cap could save me from future headaches.

Where to Buy

I explored multiple avenues for purchasing the coolant cap, including local auto parts stores, online retailers, and dealership parts departments. Each option had its pros and cons. Local stores allowed me to see the product in person, while online retailers often had a broader selection and competitive prices. I also considered the convenience of shipping times, especially if I needed the cap quickly.

Installation Process

Once I had my new coolant cap in hand, I was ready to install it. The process was straightforward, but I made sure to follow a few steps carefully. I allowed my engine to cool completely, removed the old cap, and inspected the sealing surface for any debris. After cleaning it, I placed the new cap on securely, ensuring it clicked into place. This simple task made a significant difference in my cooling system’s performance.

Final Thoughts

After replacing the engine coolant cap on my E90, I felt a sense of accomplishment. It was a relatively simple task that had a big impact on the health of my engine. By following the steps outlined in this guide, I was able to make an informed decision and ensure that my vehicle runs smoothly. Regular maintenance, including keeping an eye on components like the coolant cap, has been a valuable part of my car care routine.

Author Profile

Jason Sorenson

Hello! I’m Jason Sorenson, and I've spent the last fifteen years immersed in the vibrant world of professional theatre, both on the road and in the iconic Broadway scene of New York City. My journey through the theatre landscape has been marked by my management roles in several acclaimed productions. I've had the privilege of working on Broadway shows such as "To Kill a Mockingbird" starring Jeff Daniels, "Meteor Shower," and "A Doll’s House, Part 2" with Laurie Metcalf. Other highlights include "Shuffle Along," "Wicked," "Glory Days," and "Cyrano De Bergerac" featuring Kevin Kline.

Since 2025, I've channeled my extensive experience in theatre into a new venture—writing an informative blog focused on personal product analysis and first-hand usage reviews. This transition from theatre management to blogging allows me to share my insights on a wide range of products, helping my readers make informed decisions.

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