2019 CX-5 Diesel Aftermarket Transmission Cooler

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Just downloaded it off Google play store ...

View attachment 303017
FORScan Lite for Android
v1.5.11
Kernel v2.3.41

The Bluetooth plug-in obdii port link is one of the recommended units from ForScan website ...

https://www.amazon.com/dp/ (commissions earned)

I also purchased the vLinker USB cable to run it from a Windows based laptop in the future (but you can break stuff with that!)
Thanks for the info. I thought we have to get a full (paid) version ForScan to get all the info you listed, including a true ATF temperature, not a fake ATF temperature which would use engine coolant temperature to display.
 
:
Southwest Ohio
:
'19 CX-5 diesel
Thanks for the info. I thought we have to get a full (paid) version ForScan to get all the info you listed, including a true ATF temperature, not a fake ATF temperature which would use engine coolant temperature to display.
It is a paid app. Minimal cost (IMHO) of a one time $6 for the android / IOS "Lite" version. I'm happy to pay that for such a powerful tool with great creator and user-based support.

The Windows version is free for a short period. They have longer paid terms available $10 - 1 year license or $20 for a 3 year.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
It is a paid app. Minimal cost (IMHO) of a one time $6 for the android / IOS "Lite" version. I'm happy to pay that for such a powerful tool with great creator and user-based support.

The Windows version is free for a short period. They have longer paid terms available $10 - 1 year license or $20 for a 3 year.
$6 one time fee for the life on ForScan “Lite”? That’s cheap, especially the price for everything has skyrocketed due to the severe inflation nowadays.
 
You should come here and do a simple “(external) ATF cooler” search here instead of Google the entire Internet for the questions you have on possibility of installing an external ATF cooler to Mazda’s SkyActiv-Drive 6-speed automatic transmission.

For SkyActiv-Drive transmission an ATF cooler is piggybacked to the transmission.

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The difference comparing to other automatic transmissions, such as the YouTube video you posted for a Mazda5, is SkyActiv-Drive pulls engine coolant into the ATF cooler to cool down the ATF which is also circulating into the ATF cooler "internally". Two lines attached to ATF cooler outside are engine coolant instead of ATF lines circulating out into the radiator or an external ATF cooler found on most other vehicles. The traditional aftermarket external ATF cooler relies on those external ATF lines to circulate the fluid into external air-cooled heat exchanger cooling down the ATF. . Since SkyActiv-Drive transmission doesn't have that, an aftermarket external ATF cooler can’t be installed unless you get a special ATF cooler adapter which comes with external ATF cooler kit.

There're modified transmission coolers adding two ATF ports commercially available for other vehicles with similar design mainly on CVT's. With this ATF cooler adapter, we can hook up an aftermarket external ATF cooler easily:

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And here’s an ATF cooler adapter for Mazda’s SkyActiv-Drive transmission only for ATF flushing purpose:

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What have you done to your CX-5 today?

2016.5 CX-5 Transmission fluid change questions

ATF flush adapter
Since it is very difficult or nearly impossible to put in a transmission cooler to cool the transmissions on the CX5 -- What would you guys think of putting in an additional cooler that cools the radiator fluid that flows into the transmission cooler and allowing this cooled radiator fluid to cool the transmission fluid? There are easily accessed radiator cooling lines that go to and from the transmission oil cooler and the addition of this proposed cooler would require very little modification.
 
:
Southwest Ohio
:
'19 CX-5 diesel
@GotRice23 now that winter is here, I was curious to know what your transmission temperatures are just driving around without towing now that you have your custom trans cooler.
 
I'm currently sniffing canbus messages in order to manually turn on the radiator fan via torque app. Current program configures the radiator fan to turn on when coolant is rather hot.
 
Since it is very difficult or nearly impossible to put in a transmission cooler to cool the transmissions on the CX5 -- What would you guys think of putting in an additional cooler that cools the radiator fluid that flows into the transmission cooler and allowing this cooled radiator fluid to cool the transmission fluid? There are easily accessed radiator cooling lines that go to and from the transmission oil cooler and the addition of this proposed cooler would require very little modification.
I think it does help but not much because the heat exchanger unit is rather small. As posted above, I think being able to control the radiator fan manually does a bigger impact to lower overall temp of everything
 
Screenshot_20211031_135552_com.astech.forscanlite.jpg

Was climbing up a rather steep hill for 5 mins while towing a 1.2 tons Caravan and I was able to take a snapshot from forscan before I got an overheat related CEL (ECT went above 122celcius). As you can see the fan was only running at 50% duty when ECT and EOT were at 103 and 107 celcius respectively.
If I could manually trigger the fan to run at 100% duty way before ECT reaches 100 celcius, I believe it should lower all the temps and keep everything within acceptable temp range including transmission temp (note that I no longer have issues with trans temp as it never went above 90 celcius, but it should help others who do not have dedicated trans cooler)
 
:
Southwest Ohio
:
'19 CX-5 diesel
@Coolpix99 same question ... What are your transmission temperatures driving around in the winter cool/cold temperatures not towing?

I'm trying to see some numbers from those who have modified their system with coolers how it effects the transmission temperatures under other conditions not just towing in the summer. Does the mod make the transmission run too cool under winter conditions?

I like your thought process on just being able to manually turn on the radiator cooling fans. That seems to be the most logical approach.
 
I actually live in Thailand, so cold start temp usually starts at about 25-30 celcius.

When not towing, trans oil temp stays around 75 celcius

I understand that in cold climate, it might be better to have a heat exchanger which circulates coolant into the unit (to heat up to operating temp quicker) as well as separate transmission oil line running to a dedicated cooler. However, I don't see any products available.

There is a function in forscan(pc version only) to activate radiator fan up to 80 duty on-demand. I only tested it when the car is not running as it was quite troublesome to do that while driving. Might worth a try to see if that actually helps lower trans temp
 
:
Southwest Ohio
:
'19 CX-5 diesel
I actually live in Thailand ...
Ahhh, that's right. I remember that. :)

The Mazda setup does seem to work both ways ... A heat exchanger indeed. When it's cold out then the coolant helps heat the trans fluid.
 
:
CX5 GT
I actually live in Thailand, so cold start temp usually starts at about 25-30 celcius.

When not towing, trans oil temp stays around 75 celcius

I understand that in cold climate, it might be better to have a heat exchanger which circulates coolant into the unit (to heat up to operating temp quicker) as well as separate transmission oil line running to a dedicated cooler. However, I don't see any products available.

There is a function in forscan(pc version only) to activate radiator fan up to 80 duty on-demand. I only tested it when the car is not running as it was quite troublesome to do that while driving. Might worth a try to see if that actually helps lower trans temp

or a bigger radiator or both radiator + better fans. At least on my tow trucks thats how they came from the factory when the tow packackr option was added.
 
Bigger radiator is definitely on my radar. I will do the manual fan control first. If that falls through, then will consider a bigger radiator.

With a help from my friend(thx to him in advance) , here is the cx5 radiator fan triggering condition
Screenshot_20211224_105308.jpg

Low speed hill climb will have our fan kicked in at 108+ celcius which, in my opinion, is too late because there is a lot of accumulated heat at that point and as you can see in this service manual, CEL starts to flash at 122C

Screenshot_20211224_104825_com.android.chrome.jpg

On another perspective, here is the radiator fan condition from Nissan x-trail (probably equivalent Qashqai in other parts of the world). I personally like this setup better as the fan full speed kicks in at 100celcius

Screenshot_20211224_105318.jpg
 
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CX5 GT
yeah I haven seen this diagram somewhere and it always made me wonder why the High fan kicks in so late. Even the Low.
Often times when I am sitting at a drive through I see temps go to 101C before the fan kicks in (thats without the AC on). With the AC in its not a problem as the Fan goes by the pressure in the system. Something else which I noticed is the engine bay of the CX5 is pretty closed from everywhere even from below. So when the temps go high in the engine bay they stay high.
If your ambient temp is not blazing hot may be remove the engine cover and the hood isolation. That way some of the heat will go to the metal hood and it would be cooled from the outside.
See if that helps a bit.
Another option that comes to mind is to drill the front mesh to let more air in. If I recall its not all of it with holes. But that may be too extreme.

All the common rail diesels I had before kept lower temps so its quite strange that the Mazda diesels keeps high temps as the petrol engines. i.e the fans algorithm, etc.
 
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@GotRice23 now that winter is here, I was curious to know what your transmission temperatures are just driving around without towing now that you have your custom trans cooler.
Hey @HyFlyer, apologies for the late response.

Prior to it cooling down in the fall, my ATF temps go up to around 150 F (65.6 C) during my 20 min drive to work. Seems that even after longer drives >1 hr, it hovered around there as the new "norm" rather than the 170-180 F (76.7 C - 82 C) I got before installation of the ATF/diff fluid change + aftermarket cooler install. Unknown if this is due to the low fluids that other owners have reported in their vehicles or if it is the aftermarket ATF cooler doing its job.

The weather has been wonky lately where I live, with average temperatures reaching no less than -1 to -5 degrees C (30.2 F to 23 F) which is uncharacteristically warm around this time of year. Based on these temperatures, there hasn't been much change with the ATF floating around the 145 F - 150 F (62.8 C - 65.6 C) with the lower end of the lower band of the environmental temperatures, of course.

There's been 2 anomalies, so I will also comment on those... There are 2 days where temps have fallen to -22 C to -30 C (-7.6 F - -22 F) here. Today was one of those days. It definitely took longer for it to warm up and my ATF temp sat around 140 F during my 20 minute drive to work.

I haven't been tracking the temperatures religiously, so I can't plot the temperatures when correlated to time aside from the 20 mins drive that I do to work and the 1-2 hrs I drive out to go hunting.

Google tells me that the optimal ATF temperature is around 170 F - 175 F (76.7 C - 79.4 C). And it seems debated whether or not you could "overcool" a transmission. I'd be interested to see people's thoughts on the matter.
 
:
Southwest Ohio
:
'19 CX-5 diesel
@GotRice23 thanks for the detailed information. Those lower ATF temps in conditions other than towing in the summer I see as a possible drawback to the added cooling.

I don't recall how you set yours up ... How hard would it be to make it switchable to turn the additional cooling circuit off when not needed?
 
@GotRice23 thanks for the detailed information. Those lower ATF temps in conditions other than towing in the summer I see as a possible drawback to the added cooling.

I don't recall how you set yours up ... How hard would it be to make it switchable to turn the additional cooling circuit off when not needed?
I'm not an expert as most of it was done by a transmission specialist, but I believe the Tru-Cool 4542 that I have installed in the vehicle does not have that capability.
 
I was able to reprogram the radiator fan through ecm reflash. Stock settings show 30% duty at 100C ECT and rising and 80% duty at 108 and rising.
I reprogrammed the low speed to start at 90C ECT and high speed (bumped to 100% duty) at 98C ECT. Will tow a Caravan up steep hills in the next two weeks, will see if that helps
 
@Coolpix99 That should be helpful to get a jump on keeping things cooler. How do you reprogram the ecm?
I use mazdaedit to reflash the PCM

After another towing trip, I can confirm that adjusting the radiator fan condition makes a significant difference in controlling the ECT and EOT (although this thread is about transmission temp, I would say it can indirectly lower TFT as well).
Stock radiator fan table doesn't leave much room between high fan duty cycle(ECT = 108C) and over temp fail safe mode (ECT = 122C) as I notice from my previous trip where ECT went up very fast after about 105C and it was too hot and too late for the fan to cool down while driving (even stopping the car would require more than 10 mins to bring it back down under 90C).
With the new parameter, the ECT never went above 101C and was able to bring down the temp much faster.
 

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