Installing Mishimoto BMW performance parts

BMW E46 3-Series Aluminum Expansion Tank, Part 4: Prototype Installation

Interested in picking up this awesome aluminum coolant expansion tank? Check out our pre-sale details linked below!

Mishimoto E46 3-Series Aluminum Expansion Tank Pre-Sale

Another update on our E46 expansion tank project! Last time we showed off some images of our prototype unit, noting the numerous precise features we built into our design. This time we are installing the tank in our test vehicle to confirm fitment with the stock shroud and all coolant connection points. In addition, we will check out clearance between the tank and the belt-drive system to ensure appropriate fitment.

Removing the Stock BMW E46 Expansion Tank

Stock BMW E46 expansion tank installed
Stock BMW E46 expansion tank installed

First we need to remove the stock tank from our test vehicle. As you can see in the image above, the stock fan shroud is the first component to come out before we tackle the expansion tank, hose connections, and mounting plate.

Stock BMW E46 expansion tank installed
Stock BMW E46 expansion tank installed

After Dan managed to spill coolant all over the garage floor (thanks, Dan!), the stock tank and mounting plate were removed from the E46.

Stock E46 expansion tank removed from vehicle
Stock E46 expansion tank removed from vehicle

Separating the tank from the mounting plate can be a challenge, especially if these pieces have been married for a long time. Once the clips are removed, we used a screwdriver, pick, or small pry bar to slowly pull up the tank away from the connections. Keep in mind that the plate is plastic and likely fragile from age, so you may need to take it easy and give it a little wiggle during removal to unstick the components.

Once apart, the level sensor can be twisted out for removal. We are left with the components below.

Stock E46 expansion tank removed from mounting plate
Stock E46 expansion tank removed from mounting plate

Mishimoto BMW E46 Expansion Tank Install

With the plastic tank removed and thrown in the garbage bin, we could now install our aluminum counterpart. Our previous install was on a new OEM mounting plate. Installing it on the well-used unit on our test vehicle would be more representative of the install performed by our customers.

We installed the level sensor and slid our tank onto the plate.

Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts

A little bit of force and an audible click notified us that the tank is seated. Tight, secure, and precise is all I can say about the fitment of this piece!

Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts

Back in the car it goes!

Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts

All coolant line fittings mated up perfectly and clicked into position. Assuming the O-rings within the stock hoses do not have any flat spots, these should be leak free.

Installing Mishimoto BMW performance parts
Installing Mishimoto BMW performance parts

A look from above!

Installing Mishimoto aluminum BMW E46 expansion tank
Installing Mishimoto aluminum BMW E46 expansion tank

Once this piece was in place, we fit the fan shroud into position!

Mishimoto aluminum E46 expansion tank installed
Mishimoto aluminum E46 expansion tank installed

Our fitment report is in! All components slid into place properly and operated leak free. Clearances were nearly identical to those of the stock expansion tank. After a few hundred miles, the sensor is functioning perfectly, and the tank is performing exactly as designed.

Additionally, we will be collecting data on external tank temperatures and any impact on the components near the tank. So far, we are seeing expansion tank temperatures equal to that of the radiator end tank, which is expected because of the aluminum construction. Our initial results showed no appreciable increases in temperatures recorded on nearby intake components. More on this testing coming soon.

Coming Up!

Now that we have a final design that fits perfectly and operates exactly like the stock expansion tank, it is time to start manufacturing our first batch of tanks! Soon we will be launching a discounted pre-sale for those interested in picking up this product.

Keep an eye out for more updates on upcoming Mishimoto BMW performance parts.

Thanks for reading!

-John

Interested in picking up this awesome aluminum coolant expansion tank? Check out our pre-sale details linked below!

Mishimoto E46 3-Series Aluminum Expansion Tank Pre-Sale

11 thoughts on “BMW E46 3-Series Aluminum Expansion Tank, Part 4: Prototype Installation”

    1. Thanks for the interest CJ! The complexity of this part is resulting in a long time-frame for manufacturing. We should be launching our discounted pre-sale in around 3 weeks and hope to ship out our first batch of orders before the end of this year.

      We will announce our discounted rate on the forums and the blog!

      -John

  1. Any updates? I’ve been trying to fab a reliable solution for this for 2 seasons of club racing/HPDE to mount to my Mishi Rad, this would be an awesome solution. Also, there is no way to select BMW 323 yr 2000 on the drop down menu to subscribe. Thanks for the development

    1. Hey Aaron,

      Thanks for the interest in our expansion tank, and the heads-up regarding the site drop-down. Our discounted pre-sale is set to launch next week, and we anticipate that our first batch of orders will be shipping out right around the middle of January. We will update our blog with details on the pre-sale as soon as it launches.

      Thanks again for the interest!
      -John

    1. Thanks for the interest in our E46 expansion tank! This product is now released, meaning our vendors likely have these in stock. Check with any of our vendors, they should be able to provide the best pricing for this kit. For search purposes, the part number for the tank is MMRT-E46-99E.

      Let me know if you need assistance locating a vendor!

      Thanks
      -John

    1. Thanks for the interest! The OE part number for this tank is 17117573781. From the looks of the fitment listing this tank should be applicable for your 318 model.

      Thanks
      -John

  2. Hello John, i ordered two radiators and expansion tanks for e46 330ci. the fittings and the installing was ok, ( first radiator+tank are installed ) but the coolant level indicator always lights up after 1 min. the coolant level is ok. filled. we will try to change the level sensor, but just pulled out from the plastic tank, and was ok. is that possible if the magnet or something tightens? can i check that is working and moving? can i see it with endoscope?

Leave a Reply

Your email address will not be published. Required fields are marked *