3.6R Aluminum Radiator Upgrade (Finally) - 40mm, Dual-Core, Plug & Play

Long post incoming. Recently finished up a project I’ve been working on for a couple of months, and figured it was time to compile it into a thread: a 3.6R 40mm Aluminum Dual Core Radiator upgrade that is fully plug and play (or at least as plug and play as possible). The radiator used is actually originally made for BL/BP EZ30. The goal behind this project was to find an aluminum radiator upgrade setup for 3.6R that could be accomplished with little to no fabrication other that what can be done with simple hand tools, and most if not all parts readily market available.

 

Before we get started, you might be asking "What's such a big deal about a 3.6R radiator?". Well, the big deal is that currently, or prior to this project at least, there were no radiator options available for 3.6R that were aluminum, a capacity upgrade, or both. Why? Because of the second upper coolant port. If the 3.6R used a single upper port, we'd have dozens of options available, and all stuff that fits 08+ STI's (the same stuff that works for GT) would also fit 3.6R. But cutting into and welding another upper port onto an already expensive aluminum radiator is something that's outside of the majority of owners capabilities.

 

 

The company that makes the radiator is “Golpher”. They make three radiator versions that are relevant to us: BL/BP EZ30 40mm, BL/BP EZ30 26mm, and BE/BH EZ30 40mm. The one that I used for this project is the BL/BP 40mm version.

 

Golpher Webstore: https://www.aliexpress.com/store/1101235148

BL/BP EZ30 40mm: https://www.aliexpress.com/item/3256803630438734.html

BL/BP EZ30 26mm: https://www.aliexpress.com/item/3256801706982365.html

BE/BH EZ30 40mm: https://www.aliexpress.com/item/3256801706939513.html

 

Credit for the genesis of this project goes to Patrick (ThreeSixMafia on the forums). He originally found Golpher’s BE/BH H6 version radiator, and did all of the original cross-platform radiator measurement research. He did his experimenting with the BE/BH version of the radiator and used the Mishimoto STI fan shroud with its original fans. He did have to make some modifications to the trans fluid lines, as well as the upper radiator stays, and the radiator cap positioning/overflow tube path was different as well. After his project, I discovered that Golpher offered the BL/BP Gen H6 version radiator, and through my own research, found that it should be much closer to direct fitment for 3.6R than the BE/BH Gen radiator, so I decided to go all out with my setup. Link to his Patrick’s work is here, we had a lot of DM back and forth between us trying to figure this whole project out:

 

As stated, the radiator is originally for a BL/BP Gen 3.0R, but fitment is nearly identical to 3.6R. The top and bottom stay mounts are identical, the upper and lower coolant hose ports are identical, and the rad cap location is identical. The only real difference between the two is the trans cooler ports: 3.0R uses 2 straight fittings, while 3.6R uses 1 straight and 1 90-degree elbow. Here's a comparison between the 3.0R & 3.6R OEM radiators (using the CSF website pictures just for comparison).

 

 

Again, since I’m not a welder and I didn’t want to have anything custom-manufactured for this project, that elbow fitting was what held this project up for the longest amount of time, as Golpher used an uncommon thread pitch fitting, and the male end is welded into the radiator so it’s unable to be changed easily. It turned out to be 9/16x24 thread (which is very near the thread pitch for common sizing AN-6 fittings, but AN-6 fittings are 9/16x18 thread so will not work). The adapter I found with the correct female end thread had another, but different, uncommon thread for its male end: 5/8x18. I finally ended up finding a 90-degree elbow fitting with 5/8x18 pitch that would work.

 

 

Being that this radiator also has an integrated trans fluid cooler just like the factory radiator, it should also increase ATF cooling efficiency as a side benefit. I’m going to be reaching out to Golpher with my project to see if they could make a version with 90-degree elbows from the get-go instead and offer it directly for 3.6R to hopefully eliminate the need for the adapter shenanigans.

 

There’s multiple ways you can go about this setup. There’s a minimum list of parts you need to get it up and running, and there’s a handful of non-essential bonus parts that are nice to have if you want a “premium” installation.

 

—Bare Minimum Parts (Basic)—

-Golpher 03-09 EZ30 H6 Aluminum Radiator 40mm Dual Core (or 26mm version) - $503 (26mm is $440)

-Mishimoto 08+ STI Aluminum Fan Shroud w/ Slim Fans (MMFS-STI-08P) *might not be necessary with 26mm rad, needed for 40mm) - $277

-BrassCraft 3/8" Female Fine Thread Flare (9/16x24) x 3/8" Male Flare Adapter - $10

-Parker Elbow Fitting 90-Degree Swivel 3/8" x 5/8-18 Thread (37982-6-6) - $13

-Various 10mm & 13mm hardware (M6 & M8) and brackets/mending plates (I opted for stainless everything)

Total: $803 ($740 for 26mm, possible as low as $463 if stock fan shroud can fit)

 

—Non-Essential Bonus Parts (Premium)—

-SPAL 12" Medium Profile Curved Blade Puller Fan (30101522) x2 *need to drill new holes in fan shroud* - $206 (can be found cheaper by googling part number)

-Mishimoto 08+ STI Aluminum Coolant Overflow Tank (MMRT-STI-08) - $202

-Samco H6 3.6 L Non-Turbo Coolant Kit (TCS700/C) - $211

-Samco Clamp Kit (CK700/C) - $30

Additional Total: $649

---

Grand Total (40mm Basic): $803

Grand Total (26mm Basic): $740 (possibly $463)

Grand Total (40mm Premium): $1452

 

 

Now onto the install: Thankfully, all of the difficulties with this project were on the research/part sourcing side. Install was a breeze. Everything fit exactly as I hoped it would and it looks *fantastic* in the bay. I fabbed up a little bracket assembly to mount the fan control module on, made out of mending plates and a t-bracket I found at Lowes. Wiring was pretty straight forward, my buddy helped me with it since I’ve never soldered before, but essentially we just chopped the plugs off the SPAL fans and soldered the plugs from the original fan control on. We also swapped out the large fan control plug as well, since I had a burn/flare issue that damaged my original plug and fan control (which we think is what murdered my original engine). A side note on the fan control: the control module is the identical part # between Legacy/Outback 3.6R and 08+ Tribeca. If you look them up on eBay, you typically find cheaper results for Tribeca than you do for Legacy/Outback, despite being exactly the same part (I paid $41 for my new unit with all three plug ends).

 

 

Radiator fitment is perfect, the entire assembly rad/shroud/fan is EXACTLY the same thickness as the OEM assembly, 5” thick, so absolutely no clearance issues. That means that it’s likely that the slim fan shroud *is* necessary for the 40mm radiator, but the 26mm should be able to use the factory fan shroud. I did have to trim about 3/4” off the three coolant hoses, and did need to get a different hose clamp for the radiator side of the lower hose, as the radiator nipple is just slightly too large for the OEM clamp. The Mishimoto overflow tank also fit perfectly, with the only caveat being that you have to rest the tank on the shroud bracket but NOT insert the bottom tab into the hole. This is the only way it will fit; using the tab hole makes the bottle contact the engine and not clear. But it holds more than firm enough with the top two screws. It actually clears better set like this than the stock bottle does when inserted into the hole, and the Mishimoto bottle is about 1.5x as thick.

 

 

Moving the rest of this to a new post as I believe I've hit the 20 image limit with this one.

Edited November 7, 2022 by Humble Rumble

 

The radiator does seem to be paying dividends. Prior to the upgrade, I’d see temperatures from 197 up to 208 while driving, and since doing the upgrade, I’m ranging from about 188 to 201. The temp pic is after my morning commute, didn’t break 201 once. Haven’t had a chance to thrash it on track to push it, but so far so good and I expect the benefits will carry to track too. I should also note that I have swapped in the STI 78C thermostat for the 82C thermostat the 3.6R comes with.

 

 

Lastly, for those curious about my gauge setup, here's what I'm running:

 

-Btssm app (Android only, $15)

-Lenovo M7 tablet

-Tactrix OpenPort 2.0

-Micro-USB to Mini-USB cable

-CD tray magnetic mount

 

It works pretty well, and since I already had the Tactrix from tuning, it was certainly a lot cheaper, easier, and quicker to set up compared to bunging, plumbing, and wiring a bunch of sensors and gauges.