The Obsessive Compulsive Guide to Radiators and Transmission Coolers

[PitbullRescuer]

I've got an odd question about the cause of the pink milkshake problem.

Would it make a difference if there was no transmission fluid flowing through the radiator, or would you still be succeptable to the coolant getting into the area the trans fluid would be, and possibly leaking out causing overheating.

I ask because for some reason the previous owner put a radiator for an automatic into my manual trans 4runner. But I guess this could also apply to someone who bypassed it by running an external cooler alone.

You would loop the trans inlet & outlet lines together so that if the radiator failed internally, you wouldn't loose all your coolant and overheat.

The reason they put one for an auto into you manual is that nobody offers one without the trans cooler in it anymore. It's just one replacement radiator and if you have a manual, you do exactly as I described above.

 

[NachoPitt]

That's good news!

I'd still love to eliminate the strawberry milkshake but as I said B&M and others advise strongly against.

BTW where is your T sensor? What would be the best place to mount one?

I don't have a gauge now and am about to do the install leaning heavily to NOT bypassing the radiator since I have a brand new one. I wonder what the combination would do? Would the radiator actually heat up the tranny fluid to a higher T making the B&M less effective?

I said I was obsessive compulsive didn't I?

Thanks,

Warren

The scanguage reads the factory temp sensor - located near the pan. I had the B&M done in series with the factory radiator on my Tacoma. The temps were slightly cooler than the water temp but not much because it was still routed through the hot raditator prior to the cooler. I read that with my scanguage. I would estimate a 20F difference between the two setups, the only difference being the Tacoma was supercharged and was done in series with the factory cooler. Same year, same scanguage, same fuel, ATF, coolant, etc.

I haven't broken one open, but my guess is that the B&M cooler has more surface area than the factory radiator. People in this thread are replying based on their experience (mine included) with these coolers. Some people are looking to avoid pink milkshake, others are looking to get cool trans temps - some both. Either way there are a lot of good valid reasons to bypass the factory transmission.

Something that you might have missed in your research is that most pink milkshakes happen around 120k+, well outside of warranty and with enough potential intervening causes that Toyota wouldn't be too concerned with fixing it. If it was happening at 35k, Toyota would have fixed this quickly.

Not sure where all the lawyer hate came from but it was a team of engineers that developed the thing. You are giving the lawyers way too much credit....

 

[UnderFire]

You would loop the trans inlet & outlet lines together so that if the radiator failed internally, you wouldn't loose all your coolant and overheat.

The reason they put one for an auto into you manual is that nobody offers one without the trans cooler in it anymore. It's just one replacement radiator and if you have a manual, you do exactly as I described above.

Interesting, I'll have to make sure and put a line between the 2 when I change my oil, Thanks!

 

[amalik]

" One could get a tranny cooler and still have the rad fail from corrosion."

Taylor you aren't really making sense here. For people who bypass their radiator; even if the inside plates corroded and even collapsed, the radiator wouldn't route to the transmission, so how would it get in there? I guess your quote makes sense for people who add the external tranny cooler as an *addition* to the radiator and not a *replacement*.

I did like Brian and just bought a new rad. Except I went with Denso. I got it from a company that sells only radiators, for I believe $270, and I have absolutely no fear of pink milkshake occuring. I remember reading on the forum a while back that Denso was one of two OEM rads, or THE OEM rad used on our trucks, though I admit I have no idea who said it at this point.

I still fail to see the logic in buying a tranny cooler rather than just getting a new rad unless you live in a really hot climate. One could get a tranny cooler and still have the rad fail from corrosion. So really someone with high mileage purchasing a tranny cooler should also get a new rad. Why not just skip the cooler and save the money and just get a new rad. Ill plan on changing mine again after I put 150k miles on it, with no fear of failure in that span.

 

[the great him]

yeup there you have it folks... we are all paranoid and doing things wrong...

 

[the great him]

...damnit, he tricked me too. stop feeding the troll guys

 

[UTEP]

The scanguage reads the factory temp sensor - located near the pan. I had the B&M done in series with the factory radiator on my Tacoma. The temps were slightly cooler than the water temp but not much because it was still routed through the hot raditator prior to the cooler. I read that with my scanguage. I would estimate a 20F difference between the two setups, the only difference being the Tacoma was supercharged and was done in series with the factory cooler. Same year, same scanguage, same fuel, ATF, coolant, etc.

I haven't broken one open, but my guess is that the B&M cooler has more surface area than the factory radiator. People in this thread are replying based on their experience (mine included) with these coolers. Some people are looking to avoid pink milkshake, others are looking to get cool trans temps - some both. Either way there are a lot of good valid reasons to bypass the factory transmission.

Something that you might have missed in your research is that most pink milkshakes happen around 120k+, well outside of warranty and with enough potential intervening causes that Toyota wouldn't be too concerned with fixing it. If it was happening at 35k, Toyota would have fixed this quickly.

Not sure where all the lawyer hate came from but it was a team of engineers that developed the thing. You are giving the lawyers way too much credit....

Thanks...

I wonder why B&M disagrees then? If it's not lawyers as suggested it is the engineers then.

This is weird... I was thinking the trans may run cooler than the radiator but that doesn't make sense either.. this would suggest the radiator doesn't cool the trans at all...right?

The options are:
Trans > radiator > Trans
Or Trans > B&M > Trans
or Trans > Radiator> B&M > Trans

Wouldn't it make sense the ATF is hotter coming out of the tranny than out of the radiator? My thinking is the ATF has to be cooler coming out of the radiator.... Trans initial has to be the hottest.... Radiator temps ~190°

Not arguing just thinking out loud....

There is clearly something else at work here... If the sensor is in the pan.... is that the best place? Where is the pan in the stream of ATF? I mean how close to the outlet and outlet T's?

Thanks for the information...

Sorry to those who I have upset. I'm used to trying to figure stuff out and not satisfied with mysteries....

Warren

 

[the great him]

i think the reasoning behind the trans fluid going through the radiator is not so much to cool the trans, but more so to regulate it... liquid to liquid cooling is much more effective, but if the radiator is keeping fluid around 180-200 depending on outside ambient temps and driving conditions -load on motor, rpms ect, then its to regulate the ATF temps in the same range... but in doing so you run the risk of the pink milkshake.

i personally think the pink milkshake comes from overheating the trans fluid too many times, and seeing such a large fluctuation in temps that it weakens the seperating compartments and causes premature break-down. -only my thoughts and i have no scientific evidence to back this up.

for those of use who are trying to regulate temps via external trans coolers or stand alone systems yes i do agree that a single cooler by itself is insufficient if towing or other wise putting heavier than normal loads on things. the the guys running bigger tires with stock gears, bumpers, sliders, skid plates(armor basically) and other things like a winch ect... i think dual coolers is probably more along the lines of necessity.

i for one have dual coolers, one with an electric fan on a termo swtich, it comes on at 180* and shuts off at 160* -it has an inline temp sending unit that automatically turns on/off the fan as needed, i can over ride this and cut out the ground to kill the fan for what ever reason i see fit, say a water crossing. i also have a temp guage, that reads the hottest temps, right out of the trans, before any coolers or anything. and now with the dual coolers, i rarely see temps over 210. i can still see temps in the 200+ range, but only on long climbs or on hot days in stop and go traffic, or out wheeling, where great loads are being placed on the trans and very slow speeds are the name of the game. even in the snow at below freezing temps, i have seen temps in the 240 range, but now with my thermo switch im sure that will be a thing of the past as i can now get air flow over the cooler even when standing still.

look through my build thread for pics of my set up

http://www.toyota-4runner.org/3rd-gen-t4rs/105400-rescue-runner-build-thread.html

feel free to ask any questions


-sorry i was being sarcastic in my earilier posts, yes this topic has come up numerous times and beaten to death, but it never fails, give it 6,7,8.... months and it comes back around again and all the new guys get to hear us old dogs bittch about it some more lol.

 

[UTEP]

i think the reasoning behind the trans fluid going through the radiator is not so much to cool the trans, but more so to regulate it... liquid to liquid cooling is much more effective, but if the radiator is keeping fluid around 180-200 depending on outside ambient temps and driving conditions -load on motor, rpms ect, then its to regulate the ATF temps in the same range... but in doing so you run the risk of the pink milkshake.

i personally think the pink milkshake comes from overheating the trans fluid too many times, and seeing such a large fluctuation in temps that it weakens the seperating compartments and causes premature break-down. -only my thoughts and i have no scientific evidence to back this up.

for those of use who are trying to regulate temps via external trans coolers or stand alone systems yes i do agree that a single cooler by itself is insufficient if towing or other wise putting heavier than normal loads on things. the the guys running bigger tires with stock gears, bumpers, sliders, skid plates(armor basically) and other things like a winch ect... i think dual coolers is probably more along the lines of necessity.

i for one have dual coolers, one with an electric fan on a termo swtich, it comes on at 180* and shuts off at 160* -it has an inline temp sending unit that automatically turns on/off the fan as needed, i can over ride this and cut out the ground to kill the fan for what ever reason i see fit, say a water crossing. i also have a temp guage, that reads the hottest temps, right out of the trans, before any coolers or anything. and now with the dual coolers, i rarely see temps over 210. i can still see temps in the 200+ range, but only on long climbs or on hot days in stop and go traffic, or out wheeling, where great loads are being placed on the trans and very slow speeds are the name of the game. even in the snow at below freezing temps, i have seen temps in the 240 range, but now with my thermo switch im sure that will be a thing of the past as i can now get air flow over the cooler even when standing still.

look through my build thread for pics of my set up

http://www.toyota-4runner.org/3rd-gen-t4rs/105400-rescue-runner-build-thread.html

feel free to ask any questions


-sorry i was being sarcastic in my earilier posts, yes this topic has come up numerous times and beaten to death, but it never fails, give it 6,7,8.... months and it comes back around again and all the new guys get to hear us old dogs bittch about it some more lol.

No problem man, were cool,

I know some things can get beat to death and believe me I read a LOT of posts!

I like your theory the ATF causes the corrosion.....not sure why but a clear variable. But that would rear its head in other models with Dexron III...

I never found an autopsied radiator...would have given some clues to the failure... Anyone ever see one?


This has put me behind on homework so I will check your build later.

Thanks for the input...you really have put some thought into your rig and that was what I was after despite my provocative titled thread.

Warren