Turner Motorsport Aluminum Coolant Expansion Tank Relocation Kit - E9x 335i (N54)

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Product Details

Hotside intakes are a very common modification for N54 powered BMWs. Here at Turner Motorsport, we found ourselves unsatisfied with all existing solutions to relocate the coolant expansion tank to the cold side of your engine bay, freeing up real estate on the hot side. We decided to make an end all be all solution for people looking to relocate your expansion tank that's compatible with both hotside intakes and factory location coldside intakes. All CAD designed in-house, our N54 aluminum expansion tank relocation kit allows you to seamlessly mount our new aluminum expansion tank on the cold side of your engine bay.

During the design process, we did everything possible to ensure no air pockets could develop in the cooling system even during spirited drives. The baffled tank is all TIG welded 5052 aluminum construction, featuring a carefully designed bleed passage. We also machined all of our bungs to accept OEM hose ends, to keep the fit and finish as OE+ as possible. Keeping with this same mindset, we made sure that coolant elevation matches OE exactly, and integrated a power steering pump reservoir mount. Our aluminum expansion tank accepts the OE coolant level sensor, bleeder screw, and coolant cap, but we include new ones with this kit, as we thought you should replace them during installation. See more about these features in the list below, and if you have any additional questions please feel free to call into our staff of skilled BMW enthusiasts at 1-800-280-6966

Find our Turner Aluminum Expansion Tank Installation Guide HERE

Features and benefits:

  • TIG welded 5052 aluminum construction, wrinkle black powder coated
  • Utilizes factory coolant capacity and expansion volume
  • CAD designed to retain OE coolant elevation, which prevents air pockets
  • Baffled tank ensures that air pockets will not be created under spirited driving conditions, and ensures accurate coolant level reading
  • Meticulously designed bleed passage prevents air pockets while the engine cools
  • All bungs machined for factory hose end compatibility (no barb fittings!) 
  • Integrated power steering reservoir mount
  • Kit includes Turner Motorsport aluminum expansion tank, Turner Motorsport wiring harness, all necessary hoses, hardware, OE level sensor, bleeder screw, and coolant cap

This product fits the following BMWs:

E9x 335i 335i 335xi 335is (N54)


*NOTE: This aluminum expansion tank is only for N54 powered 335i vehicles. If you are looking for the Turner Motorsport aluminum coolant expansion tank relocation kit for your 135i, see T#568368



Qty Description T# Part#
1 Genuine BMW Expansion Tank to Upper Radiator Hose - E90 335d T#46422 17127803838
1 Coolant Level Sensor for Late E36 6-cyl, Early E39 528 T#1625 61318360855~TMS
1 OEM Behr Coolant Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 T#2766 17111742231~OEB
1 Turner Aluminum Expansion Tank T#568365 021942TMS01~A
1 N54 Expansion Tank Wire Harness T#568366 021942TMS05~A
1 Dayco Molded Heater Hose T#568367 80418~DAY
1 N54 Aluminum Coolant Expansion Tank Relocation Kit - 335i T#568345 021942TMS11~A
1 Flared Coolant Connection Line T#577607 013178ECS03~A

We have a 20-day return policy, which means you have 20 days after receiving your item(s) to request a return. Please note we charge a 25% restocking fee on all returns. To be eligible for a return, your item must be in the same original/new condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase. To start a return, you can contact us at Items sent back to us without first requesting a return will not be accepted. You can always contact us for any return question at Please inspect your order upon arrival, and contact us immediately if the item is defective, damaged or if you received the wrong item, so that we can evaluate the issue and make it right.

Exceptions/non-returnable items:

Certain items cannot be returned, like sale items, perishable goods, custom products (such as special orders or personalized items), hazardous materials, flammable liquids, and/or gases. Please get in touch if you have questions or concerns about your specific item. Unfortunately, we cannot accept returns on sale items or gift cards.


The fastest way to ensure you get what you want is to return the item you have, and once the return is accepted, make a separate purchase for the new item.


We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method. Please remember, it can take some time for your bank or credit card company to process and post the refund.