How can I check for "pink milkshake"?

dbsoundman

New member
OK, this whole "pink milkshake" thing is kind of worrying me, even though I doubt my T4R has it going on at this point (transmission runs like a champ). I understand how it's caused, but given where it actually tends to show up, I'm curious if it's really possible to check for this condition without draining the transmission. Can I just check the dipstick instead? I just bought my 2000 T4R with 147k on it and I don't have access to most of the maintenance records so I'm assuming the radiator is the original, and it will be at least a couple of months before I get around to possibly replacing it and adding a transmission cooler. For that matter, if I don't have pink milkshake, can I just put in a transmission cooler, keep the original radiator, and call it good? I'd like to hear your opinions, thanks!
 
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You can install a trans cooler without replacing the radiator, that's what I did. You would have to bypass the stock cooler to call it good though. The B&M cooler is only like $55 on amazon, you just need to pick up a few extra feet of 3/8" trans hose and maybe a quart or two of atf to do the install.

p.s.- with the passing of prop 64 I'm seriously considering moving to CO haha
 
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You can install a trans cooler without replacing the radiator, that's what I did. You would have to bypass the stock cooler to call it good though. The B&M cooler is only like $55 on amazon, you just need to pick up a few extra feet of 3/8" trans hose and maybe a quart or two of atf to do the install.

p.s.- with the passing of prop 64 I'm seriously considering moving to CO haha

I had read that some people bypass the stock cooler, and others run it in series with the external one, is there any real advantage to either setup? The installation process will likely be a thread on its own, once I read up on others' installs...
 
^yeah the advantage of bypassing it is it completely eliminates the possibility of the milkshake happening. the milkshake is still possible if installed in series.
 
Right, but assuming the radiator and the trans cooler are new, does series connection have an advantage? Or even then is it not worth the risk?
 
You can install a trans cooler without replacing the radiator, that's what I did. The B&M cooler is only like $55 on amazon, you just need to pick up a few extra feet of 3/8" trans hose and maybe a quart or two of atf to do the install.

p.s.- with the passing of prop 64 I'm seriously considering moving to CO haha
Electrolysis is the reason these radiators are failing. Aluminum simply does not corrode unless there is electrical current present.

ELECTROLYSIS:
What it is; How to Test for it; and Ways to Prevent it

WHAT IS ELECTROLYSIS?

Electrolysis is the result of electricity flowing through your cooling system and causing an electrochemical charge across the aluminum. This results in rapid corrosion and severe damage to the components in your cooling system including discoloration, pitting, flaking, and pinholes. Most common in late model vehicles, hot rods and street rods, electrolysis will usually occur if there is a defective or missing ground on one of the numerous potential electrical sources.

HOW CAN I TEST FOR ELECTROLYSIS?

To test if your cooling system has been affected by electrolysis, you will need to test the voltage in your cooling system. The first step is to connect the negative lead of a volt/ohm meter to the battery ground. Then, carefully insert the positive lead of the volt/ohm meter into the coolant inside the radiator without contacting the filler neck. If the result is more than 0.10 V, this indicates that there is an electrical current flowing through the system. Continue to check the voltage between the coolant and (1) the engine (2) the frame by touching the negative lead to each respectively. Repeat test with the positive lead touching the radiator instead of the coolant.
A simple and usually effective way to try and determine the faulty electrical source is to conduct this test with the engine running and all vehicle accessories on. Have a friend or coworker systematically switch on and off components of the car as you monitor the meter (in some instances, fuses need to be removed in order to switch the accessory off. You may also want to test with the ignition off). If voltage drops when disconnecting an electrical circuit, that circuit represents a likely electrical source.


WAYS TO PREVENT ELECTROLYSIS:

Unfortunately, only the careful monitoring and proper maintenance of your cooling and electrical system can really prevent electrolysis from destroying your system. ALWAYS make sure the radiator is not used as a ground and that all components are functioning properly. Periodically test your system and check for any discoloration or pinholes – especially around the tube-to-header joints and tubes near the center of the core by the electric fan mounts.
 
It's up to you if you wanna risk it, it may provide additional cooling while towing or something. But with 215k miles on my new to me runner I didn't want to risk it so I bypassed it and now I never have to worry about it. I also didn't feel like spending money for a new radiator when I didn't need one yet.
 
The concern with a complete bypass of the internal cooler, that that the ATF doesn't get warm enough to function as it should, and causing premature wear on the trans. My mechanic also stated he has ran this set-up with a complete by pass and one coming out of the internal cooler and the internal cooler, then connected to the external cooler, cooled better than just the external cooler. He suggested I replace radiator and add the external cooler in line for optimal cooling and heating of ATF. The new rad would greatly reduce the chance of milkshake.
 
The concern with a complete bypass of the internal cooler, that that the ATF doesn't get warm enough to function as it should, and causing premature wear on the trans. My mechanic also stated he has ran this set-up with a complete by pass and one coming out of the internal cooler and the internal cooler, then connected to the external cooler, cooled better than just the external cooler. He suggested I replace radiator and add the external cooler in line for optimal cooling and heating of ATF. The new rad would greatly reduce the chance of milkshake.

The B&M cooler states it has a thermal bypass which basically routes fluid from end to end so that it warms up faster. It eliminates it flowing through the fins until it's reached proper operating temperature.
 
There is NO down side to eliminating running it through the radiator. It's the only way to guarantee you will NEVER get the milkshake.
 
Ok, so if possible replace the radiator, and either way check specs of b&m cooler to see if it bypasses when fluid is cold. But still, what is the best way to determine if I even have the problem?
 
Electrolysis is the reason these radiators are failing. Aluminum simply does not corrode unless there is electrical current present.

Are you sure about this? I'm in a off road club with a 15 year toyota dealer tech and he told me that there is a physical part that fails internally due to vibration over the life of the vehicle.

I guess it doesn't matter what the actual cause is when preventing it is relatively inexpensive and easy.
 
Does your truck still move? If so, you don't have it.

^ so once it happens, its like zero to broken in no time? There is no warning? So if i check by opening up my radiator cap once a week, and it happens the day after i check and find no milkshake, im still screwed?
 
Since no one has answered your question on how to tell if you're at risk I'm going to say pull the dip stick and look at the fluid. Google what good transmission fluid is supposed to look like and compare. Finger the radiator overflow tank and see what the fluid looks like. Better yet get something that will reach down to the bottom of the overflow tank and scrape the bottom. Maybe it will show something but I'm not 100% sure as I don't own a 4runner yet. Good luck. Also check the 3rd Gen Buyers Guide on this forum. Lots of info on the milkshake issue there.
 
^ so once it happens, its like zero to broken in no time? There is no warning? So if i check by opening up my radiator cap once a week, and it happens the day after i check and find no milkshake, im still screwed?

Yes! When it happens, it's happens, no warning. When it does happen, coolant mixes with the ATF, goes into the trans, coats the clutches and you're F'd.
 

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