Heating and Cooling› Overflow Tanks and Catch Cans

Rein Automotive

Coolant Overflow Reservoir

$164.40

SKU: 17111741167.Rein

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Easy — 1–2 hours

Overview

It functions as an overflow bottle, capturing expanded coolant and maintaining system pressure. This component is crucial for ensuring the radiator remains full and the cooling system operates efficiently.
Show original supplier description
The Rein Automotive coolant expansion tank serves as a vital component of your BMW's cooling system. Also known as an overflow bottle, its primary function is to manage the expansion and contraction of engine coolant due to temperature changes. It safely captures excess coolant, maintains system pressure, and ensures the radiator is adequately supplied, preventing inefficiencies and potential damage. Crafted from 100% virgin plastic, this expansion tank is engineered to withstand continuous heat cycles, resisting premature cracking and coolant loss that can occur with age and exposure to extreme temperatures. The unit does not include the expansion tank cap or coolant level sensor, which must be sourced separately. Symptoms of a failing expansion tank can include foggy or opaque plastic, making it difficult to read the coolant level, and leaks, typically originating from seams or seals. A compromised tank can lead to a loss of cooling system pressure, reducing the coolant's boiling point and potentially causing engine overheating. Regular inspection and timely replacement are recommended, especially when installing a new radiator. This Rein Automotive expansion tank is compatible with a range of BMW models including the 540i, 740i, 740iL, 750iL, 840Ci, 850Ci, 850CSi, and 850i.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandRein Automotive
Part Number17111741167.Rein
CategoryHeating and Cooling

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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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