Chase Bays Tucked Aluminum Radiator - BMW E30 / E36 / E46


SKU: CB-E306RAD-15

The all new Chase Bays Tucked Radiator for BMW is finally here!  It's designed to free up space in BMW engine bays, improve cooling performance & Aesthetics.  This radiator is a cooling upgrade, with more fluid capacity than stock, more direct airflow, & dual pass design. It's mounted under the core support to open up to 6" of space. This radiator has been rigorously track tested on our Chase Bays E36 drift car & on countless race/drift/show winning builds.

We've designed this all aluminum radiator to fill every bit of space under the core support while still being able to run 16" electric fan. Requires some light cutting of front core support. More mod info below. We've integrated features no other competitor is offering. From fan sizing to modularity.


We formerly sold our Radiator with a Fan Shroud, until Nov 2019. This was a great way to mount fans (Mounting fans directly to core will void your warranty and ruin the Radiator) and to increase cooling efficiency. The only problem is anything past 12mph...shrouds can actually restrict flow. We changed to fan brackets built into the radiator and no complete covering shroud. This decreased the price $175 dollars AND increased cooling efficiency. =O


• Chase Bays 16 Ultra HD Fan  |  2,200 CFM |  $170

It's important that the fan is on its own relay w/ proper sized wiring & fill point is the highest point in the system. These 2 things are commonly overlooked.   We make a Dual Fan Relay Harness w/ 180º F Thermoswitch that simplifies the wiring.  We don't currently have a single fan relay harness, but will soon.

WARNING: DON'T ATTACH FAN DIRECTLY TO RADIATOR VIA FAN ZIP TIES. Over time this can wear through the core & puncture it.  Aluminum on radiator cores is very thin. This will immediately void your radiator warranty

Fill Point

Top of our radiator sits 6" lower than stock, so you have to make a new fill point. The 1st step is an inline filler neck, Click Here

Proper filler neck setup makes hose selection easier. We recommend on radiator itself w/ Raised Inline Filler Neck. (see photo) Select -20AN for 1 side of Filler Neck under options, other side will be hoses you choose. If you're using OE Push-On style Silicone Hoses, you'd select "1.5mm Normal Hose" for 1 option & "-20AN" for other. The -20AN side will thread right into the radiator then twist the filler neck onto that. W/ the thick O-Ring Seal on both sides, getting the filler neck 0º vertical is easy w/ adjustment of both sides. Other option is putting it on upper water neck which requires some fab work.

Modular Inlet/Outlet & Reversible Orientation

Radiator was designed to be reversible w/ interchangeable inlet/outlet types. The radiator inlet/outlet have to be on the same side b/c of the dual pass design. It looks the same on top & bottom & brackets are centered.

The inlet/outlet are -20AN female threads. Just install the adapters you need. If you change your mind later, Just thread on new adapters. We offer OE style in 1.38", -16AN, & -20AN. We recommend you put radiator inlet/outlet closer to upper water neck since that hose is more visible.

We don't recommend -16AN for 400hp+ setups!  The stock inner diameter of hose for BMW is 1.5" / 38mm. -16AN is 1" & -20AN is 1.25". By going w/ -16AN, you create restriction & reduce flow by 34%.

Factory hoses don't work.  We piece together silicone hose bends w/ small joining couplers & use Gates Heat Shrink Clamps for a seamless install. We've been drifting our E36 non stop w/ no issues with this. Click here to set your hoses up.

Eliminate the BMW expansion tank w/ this radiator if you place the fill point on the radiator as shown above. Just use a sufficient plug on the side inlet under the intake manifold & the fill point is on the radiator. This applies to M50, M52, S50, S52, S54, M60, M62, S62, etc. See below pic

Dual Pass Design

Coolant passes through TWO times instead of ONE for TWICE the cooling at half the size. Both inlets are on the same side of the radiator & a plate is welded inside b/w the 2 inlets. The radiator has 2 L brackets on each side that bolt to your core support. This radiator doesn't use any OEM radiator mounting points.

Pressure Tested

Each radiator is water pressure tested to 40psi. Your radiator shouldn’t see more than 16-19psi before the radiator cap spring does its job & expands into the overflow.

22" Wide x 17" Tall x 3.5" Thick (3" Core)

Due to the BMW Radiator being smaller than our Nissan offering, generally anything over 450hp will need a larger radiator.

Chassis Mods

E30 lower bar has to be cut (see photos) & hood latch has to be removed plus surrounding hood latch metal trimmed. The lower bar isn't structural.

E36 slight trim to the upper grille valence on left & right side.

E46 requires no trimming at all.

You can’t run AC w/ this radiator since it takes its place.  You could custom fabricate a forward mounted condenser & extended lines.  

An intercooler can work w/ some metal valance trimming on the E30.  For the E36 & E46 light bumper trimming

FAQ, Product Revisions, & Fun Facts