Good for you on keeping up with regular maintenance and flush intervals, but that's not going to prevent your radiator from failing due to vibration. I'd rather spend a couple hundred to replace the radiator every 100k miles than risk having to replace a transmission. Just my opinion and your mileage may vary.
Transmission cooler: to by-pass the radiator or not to by-pass it
- Thread starter Drcoffee
- Start date
4Runner4Leon
Senior Member
^^ Totally agree. I first heard about "preventative radiator replacement" when a Lexus tech suggested I replace the 10 year old radiator in my Lexus, and I thought he was just trying to sell me something I didn't need. I did it anyway as I was giving the Lexus to my daughter and she was a new driver, so the last thing I wanted was for her to have a breakdown somewhere.
A few years later I was removing the radiator hose in my dad's '01 Camry to get access to something, and the plastic radiator outlet literally crumbled in my hands. That's when I realized just how brittle these plastic radiators become with age, no matter how good you are about maintenance.
I now always replace plastic radiators at 10 years or less.
TonyB66
New member
And since the 3rd gen is probably the easiest vehicle I've owned to perform a radiator swap, and that the price is not so bad either, it seems like the logical thing to do alright...
That said, plastic going through many heat cycles is something that I have always eliminated by going all-aluminum, and I'll do so here too at some point in the next few years (new rad in 2018).
thundercloud01
New member
Resurrecting this thread...
I'm about to put in the more expensive $400 OEM toyota radiator (japan one, not the taiwan one). I use my truck for daily driving only, highway miles.
If I want utmost reliability does a medium cooler in-series like the 70268 help AT ALL? or is it negligible and am I fine with a new version of the radiator that lasted until now 206k miles..
Appreciate ideas. I would love to do anything that future proofs my truck but if it's totally unnecessary I haven't figured it out yet as most bypass which I don't want to do
I'm about to put in the more expensive $400 OEM toyota radiator (japan one, not the taiwan one). I use my truck for daily driving only, highway miles.
If I want utmost reliability does a medium cooler in-series like the 70268 help AT ALL? or is it negligible and am I fine with a new version of the radiator that lasted until now 206k miles..
Appreciate ideas. I would love to do anything that future proofs my truck but if it's totally unnecessary I haven't figured it out yet as most bypass which I don't want to do
Endlessblockades
Senior Member
RE: What Jered Collins said: There isn't a problem with bypassing the cooling tank using a dedicated transmission cooler on OEM radiators. Also, no reason to wait 100k miles to replace fluid when you can easily keep it fresh with a drain-and-fill anytime you have a few minutes. Adding a $25 Magnefine magnetic filter on the AT return line is some inexpensive peace of mind as well. I would recommend finding out what temp your ATF is working at before you get into a lot of plumbing you might not need for highway commuting. I never had a worry until I got around to programming my UltraGauge to show AT temp and saw 249 degrees at max off-road load. That scared me straight and I now cruise at 150 highway and 175 max and can now worry about being too cool. LOL.
spartacus
Senior Member
I dont replace mine every 100000 miles. The Japan manufactured oem radiator is way better mine lasted 14 years before I broke the over flow nipple, my fault. I replaced it with the cheaper oem version because the dealer only had those in stock and have had no issues in the last 6 years, its still in good shape. Transmission cooler in series are great at keeping the tranny Temps down while off roading or climbing hills. In colder climates, in series is better to get the atf temp up during winter. My next radiator change would be an all aluminium champion radiator.
thundercloud01
New member
Okay thanks for sharing y'alls experiences. I guess I'm wondering if the cooler will make it TOO COOL given there is no weight (I keep it stock) and it's not off-road.
phattyduck
Elite Member
Extra plumbing will have its own reliability issues. If you change the radiator and transmission fluid on schedule, you won't have corrosion issues in the stock trans cooler connections (especially in SoCal!). I'd leave it 100% stock for your goals and use patterns.
As soon as you tow or do significant offroading, then an aftermarket cooler becomes much more important... and you can have the discussion of plumbing styles.
-Charlie
19963.4lsr5
New member
I agree, normal street driving with the converter locked up puts zero heat into the trans.
The trans oil pan temp is more important to me than the temp monitored by the system. It’s after the fact.
Buy a infrared temp gun and gun the black oil pan temp at the end of a trip.
I have a smaller trans cooler on my 97 SR5. the big TrueCool is on the 97 Limited Puppy Hauler (totally bypassed) and my pan temp on a 95 degree day is around 130f at my pan.
Sent from my iPhone using Tapatalk
Bypass
I read through this whole thread before the milkshake happened to me. Now read it again after the milkshake. Once you taste that sweet strawberry, this will not even be a question. Bypass.
I don't think anyone should trust a radiator, old or new, to save their transmission. This was a design flaw by Toyota--a fail-deadly design.
Granted, I had a pretty severe use case. But having gone through this, in a truck that seemed like it would last forever, I would not trust any radiator of any age or quality to save my transmission. It really is a no-brainer, that I think you just have to experience to understand.
I would compare the price of a remanufactured trans, or even just a rebuild, to that of a decent trans cooler. I'm looking at the junkyard swap route that will cost me a thousand or more when it's all said and done. For a trans that could be more junk than mine.
For those concerned about overheating or underheating, you can monitor the temp. [MENTION=120071]mtbtim[/MENTION] - Timmy the Toolman - has videos on installing a gauge (if needed). I also like his idea of an OBD extension connected to a bluetooth reader, connected to the Torque Pro app. Monitor the temps during extremes until you get peace of mind.
Last comment - There is a theory on the forums that you can catch the milkshake when it happens, and you'll be fine if you stop driving immediately. This is what I did. I pulled over as soon as it slipped on me. But there was so much coolant already in the trans that I must have driven several miles until the slip occurred. No warning light came on, no unusual noises, no smell... nothing detectable until the slip, but by then it is too late.
I read through this whole thread before the milkshake happened to me. Now read it again after the milkshake. Once you taste that sweet strawberry, this will not even be a question. Bypass.
I don't think anyone should trust a radiator, old or new, to save their transmission. This was a design flaw by Toyota--a fail-deadly design.
Granted, I had a pretty severe use case. But having gone through this, in a truck that seemed like it would last forever, I would not trust any radiator of any age or quality to save my transmission. It really is a no-brainer, that I think you just have to experience to understand.
I would compare the price of a remanufactured trans, or even just a rebuild, to that of a decent trans cooler. I'm looking at the junkyard swap route that will cost me a thousand or more when it's all said and done. For a trans that could be more junk than mine.
For those concerned about overheating or underheating, you can monitor the temp. [MENTION=120071]mtbtim[/MENTION] - Timmy the Toolman - has videos on installing a gauge (if needed). I also like his idea of an OBD extension connected to a bluetooth reader, connected to the Torque Pro app. Monitor the temps during extremes until you get peace of mind.
Last comment - There is a theory on the forums that you can catch the milkshake when it happens, and you'll be fine if you stop driving immediately. This is what I did. I pulled over as soon as it slipped on me. But there was so much coolant already in the trans that I must have driven several miles until the slip occurred. No warning light came on, no unusual noises, no smell... nothing detectable until the slip, but by then it is too late.
A design flaw would be something that happens within the first 50-60k miles of use. Hell, even 100k miles. Almost every major manufacturer uses an in radiator transmission cooler (sometimes combined with an external cooler) as well. If you can show me that the coolant was flushed every 30k miles or 3 years then I'll agree with you. Until then, it was a lack of regular maintenance that caused the transmission cooler to fail.
It's like trying to blaming Toyota when your lower ball joint fails at over 100k miles. Those are a wear item as well. Preventative maintenance and service intervals are a key part of vehicle longevity.
cl4Rk
Member
I catch myself thinking all the time: “Poor desi… wait… 20 years / 200k miles before replacing a wear item… Excellent design!!” LOL
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blairracd
New member
Exactly this... Many car-ignorant people try to say my 4runner sucks and is too old and needs replacing whenever I need to fix something. Then I "well, actually" them and let them know it's over 20 years old and has close to 300k miles. There's nothing wrong with needed to replace very old stuff.
It's not like a Chevy that has several recalls months after release, or a Dodge with less than 100k miles that needs a new transmission.
mtbtim
Elite Member
On my 2000 4runner, I'm still running my trans cooler in-series with the radiator cooler and I'm ok with that set-up. I might bypass it one day, but for now, I'm going to leave it as is. I do really think the pink milkshake is a pretty rare occurrence, but yeah, bypassing will take out any risk of it happening.
On my 1998 4runner, I recently decided to do the bypass on it using a Hayden 699 cooler that has a pressure bypass to help the trans get up to operating temp quicker. So far, the temps look pretty good. I took it on a trip at the beginning of March to Death Valley and it did well. Coming back from Death Valley, we drove over the mountain pass near Kirkwood and ran into a snow storm. My trans temp stayed pretty low, low 100's with the ambient temp so cold. So, the pressure bypass didn't work as well as I thought it would. But, I know my 2000 with the cooler ran in-series with the stock cooler would have recorded some lows trans temps as well.
What it comes down to is what's the lesser of the two evils, running too hot or running too cold? Heat is the big killer of automatic transmissions so I'm ok with running a bit cold at times in order to run cooler during the warmer months and during the times I'm really pushing my rig.
I use to use the Bluetooth reader sending info to the Torque Pro app but now I just run scan gauge tools in both my rigs. By the way, I'm Timmy the Toolman.
Here's a video of me installing the Hayden 699 cooler on my 98 4runner.
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HiluxSurf SSR-G
Senior Member
I would install an auxiliary atf cooler in-line after the stock atf cooler. this is for the "just-in-case" mountain trips that may come or I may need to help a friend tow his car. it will also help extend the life of the transmission by lowering the atf temp
Mark_BC
Senior Member
I sort of agree. But these are catastrophic failures, more so the LBJ than pink milkshake. The LBJ's are a design flaw, they should be under compression not tension. It's a safety issue.
I'm gonna install Timmy's latest cooler. I have totally bypassed the radiator with a little B&M cooler that's too little. Last summer it briefly got up to 230 F climbing a hill. I stopped pretty fast to let it cool down. This summer I'm doing another trip to the interior in August and last year it got up to 120 F, hotter than Las Vegas ever has, so I want to be prepared. And I don't have A/C...
Tim, can't thank you enough for your all your help online and on YouTube. I'm a very basic diy'er, who started fixing his own stuff due to lack of money and lack of money alone. I have a Haynes manual, and should probably buy the fsm instead, but for now most of my research is on YouTube and forums. I don't feel comfortable watching other people's videos then getting straight to work on the truck. I might watch other videos out of curiosity but always return to your videos when it's time to actually do the job. The level of detail is suitable for idiots like me, and I think even experienced people might learn some things from you.
Endlessblockades
Senior Member
Tim rules and the FSM for most years is below. I've seen a more comprehensive DL link somewhere here, but.....
3rd Gen FAQ, Tutorials, & Documentation Reference v2 - Toyota 4Runner Forum - Largest 4Runner Forum
Thank you!
