Transmission cooler: to by-pass the radiator or not to by-pass it

[Drcoffee]

yeah probably untill my motor started over heating and then it would start cooking my tranny fluid faster than my dual coolers could cool the temps back down...

we'll just have to disagree here. You have two coolers which should bring down the temp by 40 degrees if air were passing over them How hot would your engine be to cook the transmission? I'm guessing here but your coolant would be somewhere north of 280*. That's just not reasaonable to assume.

yeah and toyota is not the only one who has this problem either... you are talking about a 15 year old vehicle here. im sure its just all internet hype... ok everyone you heard it hear first get rid of your external coolers and go back to they radiator, it works just fine and we are making a mountain out of a mole hill...


sleep is a crutch and i have nods...

Don't put words in my mouth. I said Replace the radiator and add a cooler. Not go back to your 15 year radiator and hope and pray.

Again, you are the exception here on this topic. You took the extra time and expense to make it work. Although I gotta wonder just how much air is getting thru all those heat-syncs and back to the radiator now.

* if that fan is a pusher, you do realzie that pushers are only fractionally as efficient as a pull fan. don't you? If you want to improve that cooler, stack both together and use a puller fan behind them. Just saying...

 

[Bigmikelakers]

This thread had me thinking. If you live in a hot place such as Arizona, would the milkshake happen much sooner on average to a 4runner then one in a cooler place like Seattle?

 

[the great him]

not necessarily, part of the problem is that most people do not flush the radiator or the transmission as often as they should, if ever. this will lead to the build up of gunk and foreign debris ect that will then start to "rot" the material. this coupled with the temp fluctuations of both the coolant and the ATF can create the problem. yes the hotter climate of Arizona could make the vehicle more prone than say if it came from North Dakota, but at the same times the colder temps on the outside of the radiator ie wind chill factor for a -30* day while drving at operating temps could be more of a stress-er than the same vehicle on a 120* day...

in reality the -30* day driving would actually be better, cause its keeping things cooler and that cold air will actually never touch the radiator as the heat will "radiate" away from the radiator and create a "buffer zone/transition zone". the ambient temps are a greater potential for risk of damage. as they inhibit cooling. its better to over cool than under cool


ps Seattle is not as cold as you might think it is, sure they get snow and ice, but so does Big Bear...

 

[Nelsonmd]

Yikes, getting a little heated here...

Drcoffee, you have to know you are going to get some heat coming in here and reviving an argument that has been had over and over again. Your argument and logic are not new, it's been covered and discussed, so don't think you have novel new evidence. That doesn't mean you are wrong though...

Also, don't make the claim that the bypassed cooler setups are insufficient at cooling/regulating and are going to cause your tranny to fail prematurely (you may not have directly said this, but you heavily imply it). I, along with lots of other here have the smaller B&M cooler installed in bypass, and I watch my ATF and engine temps on my SG2, and they stay at 191° for the engine temp, and around 120-160° for the ATF. I think in the summer the ATF might have gone up to around 180°. Now I am not saying that this proves anything, but it can disprove something, and it is more than just 1 or 2 datapoints here. Many vehicles have been designed from the factory with a separate transmission cooler, so it is an accepted automotive design.

Yes, liquid to liquid heat exchangers are more efficient than air to liquid, but the temperature gradient on the air to liquid coolers is WAY bigger than the liquid to liquid cooler in this case, so efficiency doesn't directly dictate how much heat is actually being exchanged. And that liquid to liquid cooler is itself cooled by the air-liquid cooler of the radiator, so you have 2 different cooling paths with these designs:

Stock:
ATF->Engine coolant->environment (via radiator)
Engine->Engine coolant->environment (via radiator)

Bypass:
ATF->environment (via cooler)
Engine->Engine coolant->environment (via radiator)

Series Cooler:
ATF->engine coolant->environment (via cooler)
Engine->engine coolant->environment (via radiator)

Which is best? Well, none of us have really done a scientific study of it, so we all just get to guess. Feel free to state your reasoning and conclusion, but don't get offended if someone disagrees with you

BTW, you are absolutely correct about the fan thing, and multiple guys have done a conversion to electric fan, but that is a much more involved project than just installing a tranny cooler, and some of the guys that have done it have had problems with the feedback/control system failing or malfunctioning.

Overall, I think this is a very interesting discussion, but because it has been had many times on various internet forums, I think additional threads on it don't bring anything new to the table unless someone does the following:

1. Sets up a verifiably accurate and reliable way to measure temps of both tranny and engine fluid, possibly at both ends of the rad and cooler (i.e. more than just the stock temp sensor).
2. Measures the temps with the different setups in a controlled manner
3. Test all setups under the same conditions (same vehicle, same ambient temp and humidity, same driving course, etc.)

Even with that, let's give the internet full credit; someone will still disagree with it. No matter how well done and bulletproof it is, someone will disagree with it because they just don't understand it, or aren't willing to understand it.

 

[Qyota]

Although I gotta wonder just how much air is getting thru all those heat-syncs and back to the radiator now.

You mean heat sink? Are you an expert on this sort of thing? You come off as one.

Using my own data, I can comfortable disagree that a small cooler is insufficient for cooling this transmission on all but the hottest days or under extreme loads.

Where's your data?

 

[IanB]

Not all coolers are created equal, and the stock liquid to liquid cooler isn't very heavy duty at all. I'd be surprised if the stock cooler could provide the same level of cooling as the smallest B&M air to liquid cooler, assuming it is properly installed, in front of the AC condenser.

 

[Fausto]

To Dr. Coffee: Thanks for bringing up this heated subject. Even if lots of flares went off, and boiling temps exceeded, it reminds us of the problem with heat.

Thanks, all, for the info, too. I was searching for info for another machine type and found this discussion. Good stuff and super pics!

For The Kid: Thank you for your Service, Sir!

 

[quicksilvr]

Thanks for bumping this, somehow I missed it several months ago. I assume Drcoffee has come to his conclusion of what he is doing on his own rig and everyone else has come to theirs. Yet, I still want to comment on a few points. Nelson and The Kid both made good points as well.

Buy a new Koyo radiator on ebay for $120 shipped and add a $^0 B&M cooler and you will never have to worry about it again.

My only concern here as a new member on T4r.org (now I question why I even give a crap, for all the heat I'm taking) is that people first understand what they are risking before they go off half-cocked. From what I have noticed from spending some time here, is that more guys than not are tight on money and a major transmission repair would not be in their budget. That's all.

Buying a new radiator from Koyo does NOT mean you never have to worry about it again, bottom line. I'll bring this point up here, because it's VERY valid: if you have a brand new radiator, and the next day you plow into a coyote or a small deer or something at 70mph, can your fluids mix? YES! I've seen this happen more than once, usually on cars because they are lower, so smaller animals can cause it. But it can still happen to a 4runner. Crack that fitting or anything else separating the two fluids and you get milkshake, new radiator and all.

Adding an external cooler alone is far far FAR from going off "half-cocked". And you are risking much less in my honest opinion.

I've monitored temps on FIVE 3rd gen 4Runners in every possibly arrangement: stock coolers, stock rigs, seperate coolers, big tires, armor, wheeling, etc. I've seen a lot of temperature data. I'm not making this stuff up when I say that a properly sized, LPD design cooler bypassing the radiator works great and will keep your transmission happy and healthy for as long as you drive the truck. And in all climate conditions in the 48 states.

To anyone thinking of deleting your radiator, if you truck doesn't look like this when you are done, rethink it.

A small single cooler will be incapable of cooling the transmission.

Just wanted to point out (again) that this is flat out wrong. (For any noob's who might be reading this....don't want you to go off all half-cocked)


I care a lot about my truck(s). I want to give my 4runner to my 2 year old son when he's 16. And I want it to have the original engine and transmission. Am I adding external coolers and bypassing the radiator cooler because I think it's riskier!? Obviously not. After seeing lots of temps in lots of situations, I personally think it's safer for everything. My .02 on the whole situation. Again.

 

[Stallion Motors]

Ok...I need the bottom line on this debate as i am doing this swap soon to our new to us t4r. Here is our situation, stock 97 limited 176,000 miles, stock radiator, no offroad use, however we will be towing two jetskis this summer.

I was dead set on bypassing the stock radiator, and adding a B&M 70268, until i read this thread about the transmission in our trucks not warming up fast enough with a external cooler only. I live in Ohio, where winters tend to get cold, and summers tend to get hot. Should i stick to my original plan of bypassing and adding the 70268?

Thanks,
Tom

 

[quicksilvr]

Ok...I need the bottom line on this debate as i am doing this swap soon to our new to us t4r. Here is our situation, stock 97 limited 176,000 miles, stock radiator, no offroad use, however we will be towing two jetskis this summer.

I was dead set on bypassing the stock radiator, and adding a B&M 70268, until i read this thread about the transmission in our trucks not warming up fast enough with a external cooler only. I live in Ohio, where winters tend to get cold, and summers tend to get hot. Should i stick to my original plan of bypassing and adding the 70268?

Thanks,
Tom

I would stick to you original plan, but use the 70264 instead of the 70268. If you are towing in the summer time, you'll have better temps with the 70264. This suggestion is if you tow regularly. If you only tow like twice all summer, just get the 70268. It'll be fine.

Your worries of it not warming up fast enough are mostly unfounded and based on speculation of others. In real life, the transmission warms up just fine with an external cooler even when it's 0 degrees out.

 

[tbst]

Go with your original plan. People have driven for hundreds of thousands of miles with external coolers on their 4Runners with no known widespread issues.

By by-passing the radiator you can guarantee you will never get a pink milkshake.

 

[Drcoffee]

Well just let us all know when Mr. Toyota calls you up and offers you a job. Then we'll take your advice to the bank.

This wasn't meant to belittle or call all those who did this mod f'ing idiots. It simply was to point out that it is not right for everyone. Someone may find it works good for them. For some who don't understand what exactly they are messing with, it is meant to help open their eyes and make an informed choice.

This cult like mod is showing just how off balance some people are. If you don't like my opinion, ignore it. You all certainly have plenty of threads to show how smart you are. Not one of you have even considered discussing the merits or even the rationale of why it was designed this way to begin with. Only the evils of the one in a million risks of a broken radiator. When in fact, most failures have come from a lack of maintenance on the owners part.

Hitting a coyote? Really! That's your argument to delete the radiator? Stupid
comes to mind but I wouldn't say that outloud. How many millions of vehicles have a cooler inside the radiator and and just how many fail? It's infitesimal.

There what's possible and what's probable. The probability is small. So small it's not worth losing sleep over.

If you plan on running over some wild life, put your skid plate on. If you plan on trailing the rig, buy a better skid plate. But to scare the daylights out of some uninformed new T4r owner is wrong. I said it before, it's your truck, go ahead and break it if you want to.

*By bypassing the radiator you'll guarrantee that you'll run your truck the way it wasn't designed to be run. Tbst is correct.

 

[quicksilvr]

Well just let us all know when Mr. Toyota calls you up and offers you a job. Then we'll take your advice to the bank.

This wasn't meant to belittle or call all those who did this mod f'ing idiots. It simply was to point out that it is not right for everyone. Someone may find it works good for them. For some who don't understand what exactly they are messing with, it is meant to help open their eyes and make an informed choice.

This cult like mod is showing just how off balance some people are. If you don't like my opinion, ignore it. You all certainly have plenty of threads to show how smart you are. Not one of you have even considered discussing the merits or even the rationale of why it was designed this way to begin with. Only the evils or the one in a million risks of a broken radiator. When in fact, most failures have come from a lack of maintenance on the owners part.

Hitting a coyote? Really! That's your argument to delete the radiator? Stupid
comes to mind but I wouldn't say that outloud. How many millions of vehicles have a cooler inside the radiator and and just how many fail? It's infitesimal.

There what's possible and what's probable. The probability is small. So small it's not worth losing sleep over.

If you plan on running over some wild life, put your skid plate on. If you plan on trailing the rig, buy a better skid plate. But to scare the daylights out of some uninformed new T4r owner is wrong. I said it before, it's your truck, go ahead and break it if you want to.

ROFL. :thumb3:

 

[quicksilvr]

Oh, and I bring up my final point.



How many people have reported problems, failures or any trouble using external coolers?

-0


How many people have reported problems, failures or any trouble using the factory cooler?


-lots




PS. Calling me stupid for pointing out that external damage can still cause a milkshake even with a new radiator is pretty infantile. A $500 collision turned into a $5300 ordeal for a friends Cadillac because of this. Say what you want to back up your stance that cooler's are dangerous and half-cocked. I think most people have stopped taking you seriously.

 

[the great him]

To Dr. Coffee: Thanks for bringing up this heated subject. Even if lots of flares went off, and boiling temps exceeded, it reminds us of the problem with heat.

Thanks, all, for the info, too. I was searching for info for another machine type and found this discussion. Good stuff and super pics!

For The Kid: Thank you for your Service, Sir!

your welcome, although most days i feel a lot of my service has been a waste of your tax dollars...

Thanks for bumping this, somehow I missed it several months ago. I assume Drcoffee has come to his conclusion of what he is doing on his own rig and everyone else has come to theirs. Yet, I still want to comment on a few points. Nelson and The Kid both made good points as well.





Buying a new radiator from Koyo does NOT mean you never have to worry about it again, bottom line. I'll bring this point up here, because it's VERY valid: if you have a brand new radiator, and the next day you plow into a coyote or a small deer or something at 70mph, can your fluids mix? YES! I've seen this happen more than once, usually on cars because they are lower, so smaller animals can cause it. But it can still happen to a 4runner. Crack that fitting or anything else separating the two fluids and you get milkshake, new radiator and all.

Adding an external cooler alone is far far FAR from going off "half-cocked". And you are risking much less in my honest opinion.

I've monitored temps on FIVE 3rd gen 4Runners in every possibly arrangement: stock coolers, stock rigs, seperate coolers, big tires, armor, wheeling, etc. I've seen a lot of temperature data. I'm not making this stuff up when I say that a properly sized, LPD design cooler bypassing the radiator works great and will keep your transmission happy and healthy for as long as you drive the truck. And in all climate conditions in the 48 states.







Just wanted to point out (again) that this is flat out wrong. (For any noob's who might be reading this....don't want you to go off all half-cocked)


I care a lot about my truck(s). I want to give my 4runner to my 2 year old son when he's 16. And I want it to have the original engine and transmission. Am I adding external coolers and bypassing the radiator cooler because I think it's riskier!? Obviously not. After seeing lots of temps in lots of situations, I personally think it's safer for everything. My .02 on the whole situation. Again.

yes, to the new guys out there, you do not have to plate the front of your radiator with trans coolers to have a safe system. i have chosen to do this because i tend to work my truck rather hard and i have seen some temps that i didnt care to. not everyone will drive their truck as hard as mine, or put as much of a load/stress on it as i do. i just wanted to be safe and cover my bases.

i think its also good to note that my trans temp is taken before the fluid enters the coolers, so im actually reading the hottest possible temps. im sure the fluid temp is significantly less by the time it leaves the the second cooler. even if my fluid temps where under 80* when they leave the second cooler and return to the trans pan, the heat from the rest of the fluid in the pan and the trans it self would quickly bring it back up to a good 120*+ with in seconds(while also cooling the fluid thats warming it as they mix...) and for anyone who thinks that 120* isnt that hot, try sticking you hand in water thats 120* then tell me its not hot. ATF is an oil based fluid, if you got ATF on you that is 120* im willing to bet that you would get a second degree burn(yes i know burns are not really measured in temps as more the length of exposure and or depth of the burn, but the oil base of ATF would intensify the burn as it would stay on your skin longer than just water...) so do i think im over-cooling, no. do i think everyone needs to run out and do dual coolers, no. do i think the smaller B&M 70628 cooler is sufficient for most people, again no... i personally thing you guys should be running the larger B&M 70624 cooler. but thats just my opinion and its based on my experiences.

 

[tbst]

I think what needs to be said has been said. If you don't want to admit that you have 0 supporting data, fine.

 

[quicksilvr]

Yes, I apologize to all reading this thread for getting a little testy in my responses. Everyone has their own opinions.

 

[Jungoes]

hey healthy debate is good now and then

this thread needs a cooler :hatsoff:

 

[tbst]

False.

This thread wasn't designed to run with one. It was designed for imminent failure instead.

 

[the great him]

fail it did.... this thread go so side tracked and derailed its not even funny... i feel bad now, this thread is one of the reasons i am not as active as i used to be.... i get too "wound up" sometimes, and its hard for me to let things go. then you compound that with what ever else is going in "my" life out side t4r, and yeah, i can act like my screen name.