New E30 Heavy Duty Aluminum Expansion Tank Kit

BMWs are well-known for their problematic cooling systems, which often lead to irreversible engine damage and hefty repair bills. The coolant expansion tank—a crucial component that holds hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory E30 expansion tank out of plastic. After decades of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for E30 owners: a heavy-duty expansion tank built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, Turner’s design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your E30 today and drive with confidence!

Just like the rest of your vehicle's major systems, the cooling system must also be addressed periodically to ensure proper cooling and component reliability. Plastic and rubber components become brittle and prone to splitting or cracking after long periods of heating and cooling cycles, especially in colder climates! The coolant itself can degrade or become contaminated, leading to potential corrosion or freezing issues. Finally, thermostats and sensors can fail completely, preventing proper cooling and/or coolant temperature readings to become inaccurate.

To make sure you are not left stranded on the side of the road with an overheated engine, we have put together this Basic Cooling System Service kit. This kit contains all of the most-likely-to-fail components, giving you peace of mind knowing your engine will continue to run cool for another 60,000+ miles.

See kit contents below for all included components.

This is a compete cooling system overhaul kit, which includes all the common cooling system failure parts bundled into a complete package. This cooling system package is for the E30 325 with the M20 engine. 

A failure in the cooling system can lead to overheating and catastrophic engine failure. Don't gamble your engine! By replacing these core items preventatively, such as the thermostat housing, radiator, and waterpump, you are defusing what could be a ticking cooling system time bomb. And if you've had a failure of one of these parts, now is the time to refresh your entire cooling system. Keep on top of the cooling needs of your engine for your own piece of mind. Potential buyers also see the upside of a properly maintained car with receipts. 

This water pump fits the following BMWs: 
1998-1991 E30 BMW 325e 325es 325i 325ic 325is 325ix