2nd Gen OEM Oil Cooler On 1st Gen

[Tatsu333]

Because of my particular use case (usually very short drives day-to-day, with the occasional brief canyon run and a few track days planned each year), I'm looking at installing the 2nd gen OEM oil cooler on my 2020 BRZ.

This is both to help with quicker oil warm-up day-to-day, and as just a little bit of extra insurance for oil temps for my very occasional harder use. For the latter, I know that it won't make a huge difference in peak oil temps, but I'm also not really convinced that's necessary anyway from the discussion in this thread. Basically - I'm comfortable that this is sufficient for my purposes.

I've picked the 2nd gen cooler over the Forester XT cooler because of the better inlet / outlet locations for the cooler itself, and I want the cleanest possible install. I know some have used the throttle-body connection route with this cooler like others used with the Forester XT cooler like in this YouTube video:

...and I know it's a really simple way to connect it, but I don't love the (admittedly minor) potential for the hoses getting rubbed by the block or belt along the way.

I'm wondering if using the 2nd gen water pipe and hoses listed alongside the oil cooler at this page would work on the 1st gen for a 100% OEM solution?

I haven't seen under the hood of a 2nd gen to get a closer look at the setup, and the diagrams online are either really unclear and have drawings that don't match up to pictures I've seen of some of the actual parts (Toyota) or totally non-existent (Subaru - no link because there are no pictures!). It appears there are four hoses and one water pipe used to connect it to the cooling system.

I watched some videos of installations of aftermarket oil coolers on 2nd gens where they remove the OEM cooler, and it looks like the two hoses from the cooler go straight down to what I presume is the water pipe in the parts list, which you can briefly see referred to as the "coolant hose bracket" around the 1:43 mark of this video:

...but then have no idea where it goes from there.

I'm guessing the water pipe is just a transition to keep the flexible hose out of danger from heat or other moving parts, and then the other two hoses from the parts list connect somewhere else downstream, but where? Are there coolant ports on the FA24 for this that aren't on the FA20? I'm going to see if I can get a look under the hood at a 2nd gen at a local dealer to see what I can see, but I'm not hopeful that I'll be able to see any further than is shown in the video linked above without being able to get under the car with the splash shields removed.

If anyone has any clearer answers on whether the 2nd gen parts can be fitted to the 1st gen, where the coolant hoses ultimately connect after the water pipe, and if there are additional parts required, I'd appreciate it!

[makinen]

Please refer my post at https://www.ft86club.com/forums/show...4&postcount=11.

And 2nd gen. has dedicated inlet and outlet for its oil cooler.


The outlet of the oil cooler could be Tee'd to the water pump inlet hose. But the inlet of the oil cooler should be routed somewhere. In my installation I routed from the electric water pump outlet.

[Teseo]

I bought 2nd gen cooler but I use the throttle body method for coolant hoses. Best bet is to buy the forester combo for hassle free/one buy

[Tatsu333]

Originally Posted by makinen

Please refer my post at https://www.ft86club.com/forums/show...4&postcount=11.

And 2nd gen. has dedicated inlet and outlet for its oil cooler.
Attachment 223185

That's great - exactly the information I needed, thanks so much! Given that info, I think I'll most likely end up just going with the throttle body method.

Originally Posted by Teseo

I bought 2nd gen cooler but I use the throttle body method for coolant hoses. Best bet is to buy the forester combo for hassle free/one buy

Even if I use the throttle body method, I think it's still better to use the 2nd gen cooler because both hose connections on the cooler are on the side nearest the throttle body instead of having to route a hose 180 degrees around the cooler.

[Luns]

Originally Posted by Tatsu333

I'm guessing the water pipe is just a transition to keep the flexible hose out of danger from heat or other moving parts, and then the other two hoses from the parts list connect somewhere else downstream, but where? Are there coolant ports on the FA24 for this that aren't on the FA20? I'm going to see if I can get a look under the hood at a 2nd gen at a local dealer to see what I can see, but I'm not hopeful that I'll be able to see any further than is shown in the video linked above without being able to get under the car with the splash shields removed.

If anyone has any clearer answers on whether the 2nd gen parts can be fitted to the 1st gen, where the coolant hoses ultimately connect after the water pipe, and if there are additional parts required, I'd appreciate it!

2nd gen has two ports that aren't present on 1st gen. One is easy to adapt; the coolant bypass pipe for second gen has an additional branch at the bottom for the oil cooler to feed coolant back in. (14050 in the figure; port B in makinen's figure)



I expect this pipe to fit perfectly on a 1st gen, either with the associated short rubber hose (616021) connecting it to the upper oil pan, or by trimming the 1st gen hose appropriately.

The other port (C on makinen's figure) is a little bit trickier. The 2nd gen upper oil pan has a pipe that exits the bottom face of the pan, then wanders around the base of the water neck. The 1st gen oil pan is completely blank where this pipe is attached. A short rubber elbow connects this pipe to the vertical pipe feeding the oil cooler.

Where this supply pipe comes out of the upper oil pan is very close to where coolant outlet is for the ATF cooler on AT cars. If you have an MT car, there's a plug (11021AA190) that could be replaced with the hose bung used on AT cars, which can be used to supply coolant for the oil cooler. The catch is that this bung is 11mm, which conveniently matches the Forester's oil cooler's coolant inlet side, but is doesn't match the 2nd gen BRZ's inlet.


This may be of interest:

https://www.importcarparts.co.uk/pro...il-cooler-kit/

this is a kit consisting of the Forester XT oil cooler, and associated pipes/hoses/fittings. The instructions describe replacing the MT plug I mentioned with an adaptor/bung included in the kit. The coolant bypass pipe matches pictures of the WRX part. I suspect this kit was assembled before the 2nd gen BRZ/GR86 came out and was never updated to use available 2nd gen parts.

[Tatsu333]

OK - so looking up the exact part numbers for the "Engine Coolant Bypass Hose. Engine Coolant Flange. Engine Coolant Pipe (Inlet)" (14050 on the diagram), it looks like the current 1st gen part number is 14050AA871 (manual) or 14050AA881 (automatic), while the corresponding 2nd gen part number (with the extra fitting for the oil cooler hose) is 14050AB511 (manual) or 14050AB531 (automatic).

The drawings don't really help, since the close-up drawings only seem to show the automatic variants (with their extra pipes for the AT cooler), but it looks like the main pipe that is common to both variants is quite different on the 2nd gen, longer overall and having an elbow turning towards the vehicle centerline after where the port is for the oil cooler.

That appears to be accounted for with a difference in piping beyond that - the 1st gen has a long elbow (99078*A) where the 2nd gen has a straight section (H616021). Not sure whether the total length ends up the same or not.

Presuming it is, you'd need to swap in the following from 2nd gen to replace the 1st gen parts 14050AA871 or 881 and 99078*A:

• 14050AB511 (manual) or 14050AB531 (automatic)
• H616021 (either)

You can re-use the two hose clamps (F92209) from the original pipe.

Are we sure that the flow direction for the connection for the AT cooler would be correct (I.E. it wouldn't oppose the flow of the inlet pipe)? If so, then yes, that would be a perfect place to connect the other end of the oil cooler circuit. I'll dig into it some more when I have more time to research if nobody knows the answer off the top of their head.

EDIT: I suppose another answer might be to return the other end of the oil cooler circuit to a T mounted in the H616021 hose...? Or is there something I'm forgetting to consider here?

[Luns]

Originally Posted by Tatsu333

That appears to be accounted for with a difference in piping beyond that - the 1st gen has a long elbow (99078*A) where the 2nd gen has a straight section (H616021). Not sure whether the total length ends up the same or not.

Presuming it is, you'd need to swap in the following from 2nd gen to replace the 1st gen parts 14050AA871 or 881 and 99078*A:

• 14050AB511 (manual) or 14050AB531 (automatic)
• H616021 (either)

You can re-use the two hose clamps (F92209) from the original pipe.

Yep, that mostly sums up that side of things. I would think you could just cut the 1st gen elbow to the appropriate length instead of getting the 2nd gen hose section. But I imagine the 2nd gen hose is cheap enough I would just get the new part.
Oh, also for the AT cars, the ATF cooler hose connection changed the other way - being straight on 1st gen, and now an elbow for 2nd gen. I'm thinking of getting that elbow for my MT car to supply the coolant; for an AT car this would be where you'd put in a tee to get your supply.

Originally Posted by Tatsu333

Are we sure that the flow direction for the connection for the AT cooler would be correct (I.E. it wouldn't oppose the flow of the inlet pipe)? If so, then yes, that would be a perfect place to connect the other end of the oil cooler circuit. I'll dig into it some more when I have more time to research if nobody knows the answer off the top of their head.

I'm certain it's the right direction. There's a figure in the 2022 New car information document that shows the coolant coming out of the pump going straight to the oil cooler and straight to the ATF warmer side-by-side on the schematic. My Acrobat reader is broken at the moment, otherwise I'd screenshot the figure. Coolant leaving the ATF warmer goes to a thermostat on the upper coolant pipe (the manifold on top of the block that sends coolant to the radiator and the cabin heater core).

Originally Posted by Tatsu333

EDIT: I suppose another answer might be to return the other end of the oil cooler circuit to a T mounted in the H616021 hose...? Or is there something I'm forgetting to consider here?

Yes, that would be an appropriate alternative, the trick being in getting an appropriate tee as the H616021 hose is a larger diameter than the 9mm return hose from the oil cooler.

[Luns]

Originally Posted by Luns

I'm certain it's the right direction. There's a figure in the 2022 New car information document that shows the coolant coming out of the pump going straight to the oil cooler and straight to the ATF warmer side-by-side on the schematic. My Acrobat reader is broken at the moment, otherwise I'd screenshot the figure. Coolant leaving the ATF warmer goes to a thermostat on the upper coolant pipe (the manifold on top of the block that sends coolant to the radiator and the cabin heater core).

My Acrobat reader decided to wake up, and I found a more apropos figure.

[Tatsu333]

OK - not sure if I'm misunderstanding that image or not, but it appears to indicate that the flow goes IN to the port (g) on the upper oil pan FROM the oil cooler, and coming OUT from the upper oil pan port (h) TO the ATF warmer.

So, that suggests logically that the flow from the port on the "Engine Coolant Bypass Hose" we had previously been discussing to the oil cooler is flowing TO the oil cooler. I think this is backed up by (f) being coolant coming "from bottom by-pass" (which I'm guessing is the port the bypass hose connects to) flowing IN to the upper oil pan.

Based on this, if I hooked up the other side of the oil cooler to the ATF warmer port, I think the two flows would be counteracting each other...?

[Luns]

Originally Posted by Tatsu333

OK - not sure if I'm misunderstanding that image or not, but it appears to indicate that the flow goes IN to the port (g) on the upper oil pan FROM the oil cooler, and coming OUT from the upper oil pan port (h) TO the ATF warmer.

Think of the water pump as sucking fluid in from g, and pumping it out port h.

Originally Posted by Tatsu333

So, that suggests logically that the flow from the port on the "Engine Coolant Bypass Hose" we had previously been discussing to the oil cooler is flowing TO the oil cooler. I think this is backed up by (f) being coolant coming "from bottom by-pass" (which I'm guessing is the port the bypass hose connects to) flowing IN to the upper oil pan.

Subaru's naming for things can be confusing, but I think anything other than the radiator (thermostat) that feeds coolant in to the water pump is referred to as a bypass. What I was referring to as the bypass line (14050) is the return line from the heater core; the parts catalog calls it a engine coolant bypass hose. It connects via the H616021 hose to port g, and it also accepts coolant from the oil cooler, to feed back into the water pump. Port f isn't relevant to us; it's internal and comes from the short block.

Coolant TO the oil cooler is by a different path not shown in the figure, but is equivalent to port h.

Originally Posted by Tatsu333

Based on this, if I hooked up the other side of the oil cooler to the ATF warmer port, I think the two flows would be counteracting each other...?

There's no counteracting; coolant from the water pump outlet goes out the ATF warmer port, through the oil cooler, and then back into the coolant bypass pipe back to the water pump inlet.

[Tatsu333]

Originally Posted by Luns

Think of the water pump as sucking fluid in from g, and pumping it out port h.

Subaru's naming for things can be confusing, but I think anything other than the radiator (thermostat) that feeds coolant in to the water pump is referred to as a bypass. What I was referring to as the bypass line (14050) is the return line from the heater core; the parts catalog calls it a engine coolant bypass hose. It connects via the H616021 hose to port g, and it also accepts coolant from the oil cooler, to feed back into the water pump. Port f isn't relevant to us; it's internal and comes from the short block.

Coolant TO the oil cooler is by a different path not shown in the figure, but is equivalent to port h.

There's no counteracting; coolant from the water pump outlet goes out the ATF warmer port, through the oil cooler, and then back into the coolant bypass pipe back to the water pump inlet.

OK - so the additional port on the 14050 bypass hose (which connects to port (g)) is where the outlet from the oil cooler should be fed from, and then use port (h) as the inlet feed for the oil cooler (using the fitting for the ATF warmer).

Do we know if there is somewhere on the FA20 block to mount part #21328AA300 (which is two hoses / pipes on a metal bracket feeding up to / down from the oil cooler), or does that mounting point not exist? Here's the image of the oil cooler parts for reference:

[Luns]

Originally Posted by Tatsu333

OK - so the additional port on the 14050 bypass hose (which connects to port (g)) is where the outlet from the oil cooler should be fed from, and then use port (h) as the inlet feed for the oil cooler (using the fitting for the ATF warmer).

Yep!

Originally Posted by Tatsu333

Do we know if there is somewhere on the FA20 block to mount part #21328AA300 (which is two hoses / pipes on a metal bracket feeding up to / down from the oil cooler), or does that mounting point not exist? Here's the image of the oil cooler parts for reference:

The FA20 timing cover already has the bosses to bolt on a coolant pipe (as used on the Forester XT) and I believe the bosses used for the FA24's coolant pipe are identical. While I didn't actually test putting a bolt into the bosses on my timing cover, I'm pretty sure they're already threaded. Worst case would be that you'd have to tap threads into them yourself, but I don't believe this to be the case.

The only detail I haven't yet nailed down is how to address the ATF port. That port is threaded on the FA24 upper oil pan, and is either plugged off with a blank for MT, or a pipe nipple is screwed in for AT cars. The FA20 MT upper oil pan has threads in that hole and a plug but I believe the threads for the MT plug to be smaller than the FA24 threads (the part numbers for the plug are different), so I don't think the FA24 pipe nipple fits an FA20 pan. The FA20 upper oil pan has the pipe nipple pressed in for AT cars and is considered to be a part of the oil pan rather than a separate part like it is for FA24.

I plan to order the FA20 plug ( 11021AA190 ) to identify what thread it is. I have a hunch it might be 1/4" BSP. Whatever it is, I'm crossing my fingers it's something we can find a 9mm hose barb for. If it is 1/4" BSP, this seems like the perfect part:

https://www.ebay.com/itm/156539268051

[makinen]

For the coolant flow direction, refer this.
https://www.ft86club.com/forums/show...4&postcount=11

[Tatsu333]

Originally Posted by makinen

For the coolant flow direction, refer this.
https://www.ft86club.com/forums/show...4&postcount=11

Thanks! Yeah - I had looked at that, but it didn't show the port for the ATF warmer and its direction of flow.