Subaru Forester CVT Cooler How To

These are the parts that I used:
Hayden Transmission Cooler
amzn.to/2Rn1tVp
Transmission Oil Hose
amzn.to/3uORQ0k
Stainless Steel Hose Clamps
amzn.to/32bjtEv
Fluid Control Thermostat
amzn.to/3a942B4
Mounting Bracket
amzn.to/3mV9Qn7
Subaru CVT Oil Type-II

[@JevaughnGraham123]

I love the fact that you didn't just buy an over expensive kit like mishimoto, loved how you sourced all the parts individually

[@MatthewHeiskell]

Thanks man! I recently did the same thing with my oil catch can. You know, cuz it has direct injection and the PCV system puts oil on the hot, top side of your intake valves causing lots of carbon build up and restricted air intake. I used a $30 universal one. I haven’t made that video yet, I’m still waiting on the 1,000 miles so I can report how much oil it collected.

[@happyhome41]

Great video. Love this ! All the facts, just the facts, no music, beautifully illustrated.

[@bruceyyyyy]

Good video! One thought: I had an external cooler attached to the 4EAT on my 2000 Outback and those style zip mounts caused abnormal wear on the radiator/condenser fins. It never failed but it did get loose and waller a hole in the fins to the point that I re did it and built a bracket to hard mount it. There weren't any leaks but I could see it becoming an issue on a long enough time line. It was super easy to do on the 2000 since the grill lifted up with the hood. Keep up the good work Matt!

[@MatthewHeiskell]

Hey Bruce! Thanks for the warning. I just went outside and checked mine. It is still very secure after nearly a year. Did you use the foam pieces that go between the two radiators? They are the real MVP \^o^/

[@bruceyyyyy]

@@MatthewHeiskell Yup! You can probably find the build thread where I did it on my 2000 if you search hard enough on the forum lol

[@TomtheDilettante]

best video I've seen on this topic so far. I just have 2 questions. (1) Are you part of the Amazon associates program and have affiliated links to these products? If so, I'll totally use them in support of this content. (2) did you pre-fill the cooler and/or bleed the lines prior to post-install start-up? I'm wondering if any air pockets in the system might prevent the thermostat from operating correctly. Great work! Thanks for sharing!

[@MatthewHeiskell]

Hey Tom, great questions! Yes, there are product links in the video description. No need to pre-fill the cooler or bleed the lines because when the fluid control thermostat is "closed" is actually still 10% open, this prevents air pockets, maintains constant system pressure, and prevents cold oil shock when the valve opens. The thermostat flows up to 20 gallons per minute, so it is certainty not the limiting factor. I've had this installed for a year without any problems. Using my Scan Gauge II to monitor the CVT temperature, it averages about 30 degree colder than normal.

[@valdius85]

@@MatthewHeiskell "cold oil shock": that makes sense. Especially in the winter.

[@bygonebob]

@@MatthewHeiskell So glad you mentioned "cold oil shock" and the "10% open" because I was a little concerned about what will happen with all the trapped oil past the thermostat when it is closed i.e. oil in the tubes + in the cooler will probably turn gelatinous or thickens during winter and cause restrictive flow or even blockage by the time it opens up. So the 10% opening prevents this from happening? I just want your confirmation. Also good to know that the thermostat is rated @ 20 gpm but what about the cooler itself? Is it also rated the same? Thank you so much for sharing all these figures including the 30% heat reduction you got from this particular model. I never got all these info from other videos. Keep it up! 👌👍

[@JDS-Dalton]

I'm definitely going to have to have this done for my '19. Was on a trail yesterday, and the way back was couple miles of steep uphill climbing. Saw temps higher than I'd like on my scangauge.

[@MatthewHeiskell]

Hey Dalton, I’m glad to hear that you’re monitoring the temps. The scan gauge is amazing, right? Yeah, add the trans cooler, it is a must for off road.

[@JDS-Dalton]

@@MatthewHeiskell that it is! That was one of the first things I got after installing the lift and skids! And definitely! Hopefully I can get it installed soon.

[@JDS-Dalton]

@@MatthewHeiskell quick question, how many quarts of the cvt fluid did you need? Just an extra one?

[@MatthewHeiskell]

Yes, just one quart. Multiply the inner cross section area by the total path length to get an accurate volume estimate. For me, it was about half a quart, but I dumped the whole thing in there haha. It was difficult for me to imagine having too much oil in a box of moving metal parts haha. An engine can have too much oil though haha, but I don’t think that I transmission can.

[@JDS-Dalton]

@@MatthewHeiskell thanks! I got the cooler you listed in the description, going to have a shop do it though, but I'll provide the oil as well as it's not a subaru specific shop.

[@rnelsontn]

Also, in your original factory configuraation, there are two hoses attached to transmission from HE; I see only one hose from HE to transmission, which I'm guessing is the return line for cooled fluid. The other three hoses disappear toward the front of the engine.

[@benson098123]

Great video. A stacked plate cooler will give you more efficient cooling for the same size. Very tidy install, great explanation.

[@milesmakale7129]

Thanks for this video! I'm getting the parts asap to do this myself!!

[@MatthewHeiskell]

Right on! 👍

[@practicaldriver]

Thanks brotha I used your video to cobble together my own CVT cooler for my SJ Forester XT!

[@MatthewHeiskell]

Right on! Glad it helped you! 😄

[@justinman1226]

Hayden 402?

[@gerardoruiz72]

how is this cooling comparing with the Mishimoto one in terms of grades?

[@pasteldecocoa1754]

thinking on doing this, i live in a hot weather country with lots of hills.

[@MatthewHeiskell]

It's a pretty easy mod, affordable too! Potentially saving you thousands in transmission repair.

[@WolfKingJS54]

I have a 2016 Crosstrek and I was thinking about doing this. So on line goes from HE to Thermostat and then from Thermostat directly to the Transmission

[@MatthewHeiskell]

Uh, follow the diagram that I made. Study it carefully.

[@rnelsontn]

I'm in the process of installing a Hayden transmission cooler on my 2019 Forester. I have watched several videos and am having a problem with how to run the hoses. Regarding the hoses you point out at 1:28 in your video.......Those are coming from the heat exchanger to the cooler and then from the cooler back to the transmission, correct? Did you just cut the original hoses and splice in sufficient hose to the thermostat and the cooler and return? Thank you for any help you can provide.

[@skiwealdo1973]

On your video diagram you're having the output of the transmission oil going into the what is the smaller spring side! What is on the derale site, it's going in where the thermostat side is this is confusing me where the output oil of the transmission goes to where? On the derale site it looks like from the transmission going out into the input thermostat bigger side is going into the thermostat bigger side not the smaller side where the spring is like what your diagram is depicting. Are you sure you have your diagram right??

[@MatthewHeiskell]

Yeah, the diagram is a bit wrong.

[@mathieupaquette2259]

would consider the towing capacity to be significantly upgraded with a modification like that on a 2020 cvt forester?

[@MatthewHeiskell]

Yes! The towing capacity was limited by the lack of a factory transmission cooler.

[@DIYDad1]

This is probably one of the most important upgrades for offroading. Especially with the cvt. I’ve seen so many videos where the cvt simply cuts power when going up steep hills and part of that is temperature. Luckily it’s pretty flat where I live but still, this is almost a necessity to prolong the life of the cvt. That and regular fluid changes which for whatever reason Subaru says it’s lifetime fluid, which we know is a lie. I’ll probably change mine out every 30k or so. Btw do you think any obd2 reader should be able to pull transmission temp? Was looking at getting one of those Bluetooth scan tools so I can see the read out with live data on my phone when I want it. But idk if they can all read trans temp.

[@MatthewHeiskell]

You're so well informed! I have a Scan Gauge II mounted to my steering column. It displays the CVT temp after you type in some codes from the official website. amzn.to/35rvivp www.scangauge.com/x-gauge-commands/2014-subaru-forester-with-cvt/

[@DIYDad1]

@@MatthewHeiskell I’ll check it out. Looks like a nice thing just to have always mounted in there for a constant read out.

[@MatthewHeiskell]

It does other stuff too. It can read and clear check engine codes. It can display a lot of other values too

[@valdius85]

Out of all the unreasonable mods you've done, this one I'd recommend even for people who still have the original front bumper. :) For now, most of my "off-road" is during the winter, with the temps around 10 deg cells (50 Freedom). They always short in time as well. Hopefully that will change one day in the future. I'd love to go camping, which includes steep inclines. I'd love to learn once how the CVT oil temps are. I think I'll install something to monitor all of the temps first to check how/if my hybrid is strained enough to justify this thing :) It's often above 100F during the summer, I wonder what the temps are on a motorways.

[@MatthewHeiskell]

Hey man, good to hear from you again! Yeah, connect a Scan Gauge to the OBD2 port to monitor the transmission temperature and many other things! It is very user friendly, you just need to type in a couple special codes to make it read the CVT temperature. Everything else is automatically displayed. Here is a great video about the setup that my friend Tom made: kzbin.info/www/bejne/fKaVq3ydaaiZZq8

[@fabianalvarezderon2172]

Hello , nice job!! I have a 2.5 2016 Forester and the light alt oil temp turn on when I drive fast for 20 minutes, you think these is a defect of this CVT transmission? In my case this happen when the temperature is high like 35 grades , for me your job is the best solution, thank you for the video , I wait your opinion

[@MatthewHeiskell]

It sounds like you transmission is overheating. Changing the transmission oil and adding a transmission cooler will help.

[@justinman1226]

why not just use the hayden 696-699 series? they use a bypass to keep the oil from being cooled until it reaches a certain temp

[@MatthewHeiskell]

I've heard bad things about those coolers with built-in fluid control. They seem like a good idea, but I've heard that they don't always work. Air bubble problems and such near the valve.

[@justinman1226]

@@MatthewHeiskell well i went with the hayden 699 on my '18 XT and so far so good. bypassed the can of beans. takes a long time to warm up after around 150 degrees, which is when im guessing the bypass opens. over the course of a loooong (300+ mile) drive, it did eventually match the coolant temp at 192, but it sure as hell beats being over the 200-210 range from before the install.

[@pinkflamingos69]

From my understanding, Subaru is picky about not changing transmission fluid before 90k or something like that, and if you do they void the warranty. Does this void the CVT's warranty?

[@maxellyou]

nice video matt. i got a 2018 2.0 xt so ill be lookin out for your uploads.

[@MatthewHeiskell]

Awesome! 😁 You have a turbo, right?

[@maxellyou]

@@MatthewHeiskell yea tiny lil turbo tucked up under the belt. It’s almost a perfect car. Got a few gripes but I’m a suby guy. I’ve owned 10 different ones. My first was a fwd 86 gl. Spare tire was where my intercooler is now lmao

[@MatthewHeiskell]

@@maxellyou Oh, very cool!

[@CHOP_AS_FRAGGED]

If i wanted to skip the thermostat and just buy hose and route it to the heat sync and radiator, wouldnt that effectively do the same thing besides helping it warm up to temp? Thanks in advance

[@MatthewHeiskell]

Yes, but I've been testing a better setup since this video. I bypassed the heat exchanger, actually completely deleted it and I just used one of the original engine coolant hoses to send the coolant back into the engine. The current transmission oil path is simple. Just using the fluid control thermostat and the tube and fin transmission cooler. It's a littler slower to warm up (slightly hurting efficiency), but it holds 170F under ALL conditions.

[@CHOP_AS_FRAGGED]

@MatthewHeiskell would you mind making a video or even short about that bro? Thanks again!!

[@MatthewHeiskell]

Yeah, I can make a quick reel. I think I've seen you on IG, right?

[@CHOP_AS_FRAGGED]

@@MatthewHeiskell yes, we talked about sway bars on there lol

[@MatthewHeiskell]

Oh, yeah, I remember, I posted the reel, check it out when you get a chance.

[@toyranchtvchannel]

Can I do this to my 2019 Subaru Ascent?

[@MatthewHeiskell]

Yeah, for sure!

[@xerxs97]

Hey there, will this setup work on the outbacks? Mine isn’t a wilderness model.

[@MatthewHeiskell]

Yup! It’s the exact same setup. But I’ve found a configuration that works a little better. It’s the same as this video’s setup, except with the heat exchanger bypassed and completely deleted.

[@4byfor]

@@MatthewHeiskellplease do a video. Thanks

[@kendalja78]

What year forester is this? Looking to do this on my 13 XV

[@MatthewHeiskell]

This was on a 19 Forester, but it will be the same for practically any Subaru.

[@subjekt5577]

How did you fill the fluid? Did you use the new lines or a pump from below?

[@MatthewHeiskell]

I added additional CVT oil through the new return line.

[@jordanyang3066]

Where do you buy the heat exchanger?

[@CHOP_AS_FRAGGED]

The car should have it

[@MatthewHeiskell]

Yup! The car already has a heat exchanger.

[@oliverbenji1807]

So I'm in a tropical country the temp is 30-35 all the time, do I need the fluid control

[@MatthewHeiskell]

Nice! You don’t need the fluid control thermostat. Just add the cooler 👍

[@Laidbache23]

Would I be able to just add the cvt coolet or would I have to also add the can of beans to it?, new to the subi world I live in the desert my temp at low speeds stays in around the 133’s and i also live on a mountain freeway so when going over that seems to kick oil temp to 138

[@MatthewHeiskell]

Are you using the Celsius temperature scale? It sounds like you should add a transmission cooler. The heat exchanger (can of beans) is already there. For max cooling, you can bypass it or eliminate it from your car. Tell me more and I’m happy to help.

[@Laidbache23]

@@MatthewHeiskell no it reads in Fahrenheit, when I’m going uphill in the summer around 60mph it’s pushing the oil temp around 138, thank you for the advice I think I’m going to add the cvt cooler do you think that would help in anyway

[@MatthewHeiskell]

Uh, those are pretty dang low temps. What transmission do you have?

[@fieldsondeer7567]

thank you

[@MatthewHeiskell]

You're welcome! 😄

[@katsooba]

How did you add oil to the trans after the install? Just pumped in half a qt through the fill plug under the car?

[@MatthewHeiskell]

That works! I just poured the same amount into the return line before connecting everything.

[@Ryan-qn4ps]

Nice! Have been thinking about doing this to mine. What year is your forester? Also, you have any worry about voiding the warranty by adding the hayden trans cooler?

[@MatthewHeiskell]

Mine is a 2019. If the CVT craps out, I'm going to put a lot of things back to stock before I take it in haha

[@Pecbs]

Very interesting solution. I've just added an Hayden 679 (plate cooler) in my 2015 Forester XT and straight after done, one friend (who is a engineer) told me that i should have installed a tube and fin model due to the loss of pressure in the transmission lines that plate coolers have as a side effect... What do you think regarding that? Did you install this plate and fin model being aware of this issue? Thanks

[@MatthewHeiskell]

Oh, that’s news to me. I just liked the tube and fin cuz it was cheap and I could see how it worked. That made me feel a little more comfortable, haha. Your plate cooler should be fine.

[@Pecbs]

​@@MatthewHeiskell Haha, nice! One thing that make me more confident is that Mishimoto WRX CVT Cooler is a stacked plate model... This models have a higher pressure drop in comparison with plate and fin models (like Hayden 679). Mishimoto did a development for Ford F150 and decided to keep plate and fin model for it due to the fewer pressure drop for almost same level of cooling. With this in mind, i'll keep 679 and see what happens next. Thanks bro!

[@dm19609721]

Excellent video...... Thanks

[@MatthewHeiskell]

Many thanks! 😄

[@ozeltzex1]

Did you use the plastic ports that came with the kit or replaced it to brass ones?

[@MatthewHeiskell]

I don’t remember using any plastic barbs, so I guess that I switched them to brass. Which ones are plastic? On the rad or the thermostat?

[@forester_overland_nz]

Awesome video as usual! Question. Would you know if a non-CVT auto trans would benefit from a Thermostat e.g. 2011 Forester? My first thought is no?

[@MatthewHeiskell]

I don’t think you NEED one for your 4EAT, but it might help if you climb hard trails. You should monitor your transmission temperature and see how it does when climbing a difficult trail.

[@forester_overland_nz]

@@MatthewHeiskell cheers for the reply. I've seen my 4EAT temp rise to 120C when I was doing a long steep sandy hill. Even with beach driving temp can go to 100C on a hot NZ summer. I reckon the cooler will help a bit but I need to know if I need a thermostat. I'm not seeing a heat exchanger on my Foz though, perhaps they're only for CVT transmission?

[@anthonyjulson8840]

​@@forester_overland_nzyour heat exchanger is more than likely built into the radiator.

[@clappedoutsubieshoopties2216]

Absolutely nothing wrong with installing one if you have larger tires or apply a lot of resistance to it (hills, trails, etc.) I run one on my Jeep and will be installing one in my Forester soon. It only takes a few overheats to significantly reduce the lift of the transmission.

[@forester_overland_nz]

@@clappedoutsubieshoopties2216 cheers!

[@85nscarola]

Bout time someone showed which port it goes to. Going to do this to my legacy this weekend. My cooler is much smaller. Do you feel as though you went too big and are overcooling? The one you bought is rated for RVs

[@MatthewHeiskell]

The fluid control thermostat prevents over cooling. I monitor my transmission temperature with my scan gauge 2. The temps are good, 150 to 160F. I used that giant cooler because when you’re off roading, you not going fast enough to get passive cooling from fast air flow.

[@85nscarola]

@@MatthewHeiskell nice. I’m putting mine in cause the trans seems to jerk and hesitate when starting after I have been driving for long period of time. Hopefully keeping it a little cooler will help cause it never does it on cool mornings. Thanks for the video. This is the only one that actually showed which line off the stock cooler was the correct one

[@jackmehoff2475]

Would this set up be okay during freezing cold months?

[@MatthewHeiskell]

Yes, that is the purpose of the fluid control thermostat 👍

[@honsolo802]

I am assuming you had to drain the transmission fluid to install?

[@MatthewHeiskell]

Nope. No need to drain the transmission oil. A little bit of oil spilled when disconnecting the original hoses, but that was replaced when adding the new quart of transmission oil to account for the additional volume of the transmission cooler and longer hoses. When the car is off, 99% of the transmission oil drains back into the transmission. No problem at all.

[@DLH-ws2xy]

Nice. Great job.

[@elneneeserio]

So will It make last longer ?

[@MatthewHeiskell]

Yes, it will prevent overheating when towing or driving steep rough trails.

[@noekaur3813]

How did you determine how much CVT oil to add? I think you said half a quart in the video.

[@MatthewHeiskell]

The volume of the added hoses and cooler can be closely estimated by taking the cross-sectional area of the inside of the hose/cooler and multiplying by the length. Basically the area of the hose in square inches times the length in inches is cubic inches, then google to convert cubic inches to fluid ounces. The hose and cooler have the same inner diameter if I remember correctly. Take the diameter, divide by 2 to get the radius, the use pi r^2 to get the area, then multiply by the total length, be sure to count all the back and forths of the cooler

[@noekaur3813]

Impressive, and here I thought you took the add fluid plug out from under the tranny to ensure you had a slight drip. I’m getting a high school or college physics professor vibe here. Thank you!

[@MatthewHeiskell]

Haha, good guess! I taught high school physics and chemistry for a few years. The fill hole drip is likely a better method though. I’m pretty sure I put the whole quart of CVT juice in there though. I just couldn’t imagine how more oil/lube could hurt a transmission. It’s still working perfectly. We just got back from another 1,000 road trip to hit some national parks.

[@noekaur3813]

I went ahead and installed it, including the half quart of oil, and now my check engine light is on. Scan Guage can’t read the code. Any idea why this might happen? I’m thinking either too much or too little trans fluid, or trans fluid pressure is low. I think I’ll have to go to the dealer to check/clear the code, but don’t really want to do that. Thanks for your ideas in advance!

[@noekaur3813]

Disregard. The check engine light wasn't there the 3rd time I turned it on.

[@charlesdu9941]

does this work for the outback too? :D

[@MatthewHeiskell]

Yes, it will be the same for the outback 👍

[@shvak2063]

Can i do this to my 19 crosstrek?

[@MatthewHeiskell]

Yes, it will be nearly identical.

[@shvak2063]

@@MatthewHeiskell i wonder how will it affect warranty

[@shvak2063]

How is this set up compared to the hayden 699 which has a built in thermostat?

[@JevaughnGraham123]

did you use the regular fittings for the thermostat

[@MatthewHeiskell]

Yeah, I think so, the ones that came with it.

[@JevaughnGraham123]

@@MatthewHeiskell okay awesome I saw where they were selling the copper or aluminium ones as well, I'll use what it comes with, thanks man, bought everything because of you

[@MatthewHeiskell]

Cool! It’s a great upgrade for the car. Remember to add cvt juice to account for the additional volume of the hoses and cooler.

[@HossamElramy3]

I still have no clue which hoses go where :| I wish there is a diagram

[@jameshughes6078]

I think there's an "R" hose marked on the return.. at least, that's how mine came from factory. It's the "top" one (middle one)

[@RigoStar1931]

Will this set up work for my 2014 2.5?

[@MatthewHeiskell]

Yes, it should be the same. You can remove the intake parts and take a look before ordering the parts.