I am taking my 4runner in for a timing belt, coolant flush, power steering flush, oil change ect. I can do this all myself, I just choose not to at this time. My question is, I believe my radiator is original with 229K miles. Should I have them put a new one in there when they do the coolant flush? Or keep the one I have and add a Transmission cooler later on my own when I have a minute?

My 4runner is used for basically daily driving, not really any road trips and moderate offroading. This may change slightly in the future but not by much.

Thanks for your opinion!

External cooler in series with the radiator helps keep the atf fluid cooler when towing going up steep hills etc, some do bypass the radiator all together to avoid pink milkshake. If the coolant system has been flushed as required and maintained and the radiator is in good shape after almost two dacades then stick with it but for around a 100 bucks you get a new denso or oem and peace of mind.

I'm a firm believer in replacing plastic tank radiators every 10 years or 100,000 miles, no matter how well taken care of.

I first heard this school of thought from a local Lexus mechanic, and thought he was nuts (I come from old school brass radiators), but I did as he suggested on my Lexus anyway (since my 16 yo daughter was driving it at the time, and I didn't want her to get stranded).

I also did this on the 4Runner when I bought it with 167K - both for the pink milkshake concern, and again, because of the plastic tanks.

Where I saw this in action was when I was replacing my dad's 2001 Camry valve cover gasket the other day - I removed the radiator hose to get access to the valve cover, and lo and behold, the entire plastic water outlet crumbled into pieces in my hands. Lesson learned - old plastic decays.

The transmission cooler is a totally separate item - I added a B&M 70264 to mine, even though it's a daily driver. I doubt I actually need it, but it's a fun project, so why not .

To answer the OP's specific question, of those two choices definetly replace the radiator. You can always add an extra cooler in series if you plan to tow up mountain passes or the like otherwise not really necessary. You'll achieve far better results at keeping trans temps down by applying judicious use of the Overdrive Over ride button up hill/mountain passes.

Luck and enjoy that Runner!

I am in the same boat as 4Runner4Leon, change the radiator, and add the cooler. You can’t go wrong with doing such. It is rather easy on these 4runners and if you have the skills to do such, DIY would save you some money to put towards a new radiator cap, plus new lower and upper radiator hoses. All OEM here.

Hmm. I am thinking of replacing the Radiator now and maybe add the extra cooler later. I didnt even think of the radiator cap and hoses so good call. Ill replace those too.

Timing belt replacement is definitely the time to replace the radiator, I wouldn't even think about it I would just do it. I ran my cooler in series with a new radiator.

I replaced my radiator last year shortly after I purchased my 3rd gen. I forgot exactly the make, but purchased it at Camelback...

Not fan of plastic on radiators. I replaced them before on other rides with all metal offerings, typically aluminum. Is there an all aluminum radiator for us that does not have the transmission cooler incorporated, which allows for all of the capacity to be used for engine coolant? I sort of doubt it...

I would definitely recommend replacing. It's just cheap insurance. I know you are getting it done at the shop but it took me maybe 30 minutes and a hundred bucks.

Also decided to bypass and install a tranny cooler, tied to the backside of the main radiator where it faces the fan- I had pretty high temps when wheeling at slow speeds so constant air circulation helped quite a bit actually. Again, just cheap insurance. On the off chance you get the pink milkshake, would you rather replace your transmission($$$), or thank the automotive gods that you spent an extra fifty on an isolated radiator?

Maybe look into getting a Scangauge or Ultragauge? There's a cheaper bluetooth unit that pairs with your phone too, forget the name. Always good idea to keep an eye on engine and transmission temps.

I'll install the B&M cooler soon. Is it actually just mounted on zip ties fed through the main radiator fins?????

That's how quite a few have done it alright. With high quality zip ties, they should last a while. I plan to use pieces of metal stock to secure it though. It should ideally "float" a little, or have some flexibility...

My vote is to replace the radiator. If you want to add a cooler at a later date, you always can. I would run it in series if I were to add one.

Definitely replace the radiator after 229K miles! It is cheap insurance. With respect to a transmission cooler, I put one in years ago when I was driving back and forth between Alabama and New York State. Prior to the cooler, I could feel the heat coming off the transmission in the cab by reaching down and feeling of the "transmission hump" between the front seats. Afterwards, little or no heat radiating through. I bypassed the radiator as to avoid the pink milkshake. I figure this too was "cheap insurance" against the pink milkshake debacles everyone talks about. I did this 12 years ago and ZERO issues. Original transmission with no problems.

I'd do the radiator first, at least. No sense in doing a timing belt job, just to have the stock radiator burst and overheat your engine.

Then do the tranny cooler as you need/want.
I have mine bypassed, and my tranny sits around 160 all the time. Of course, I live at 60ft above sea level with barely a hill, so your mileage may vary.



That's how mine came, and I've not had any issues. When I replaced my radiator, I had to clip the zip ties it came with and just used normal ones in place, with no ill effect.

Radiator, Timing Belt and Lower Ball Joints are all on the FSM 100K replace schedule

You can add an inline aux trans cooler at anytime