Jin_Chris

I am in the middle of doing 2nd T-belt/waterpump etc maintenance (97 4Runner SR5 Auto 138k miles). The first one was done about 75k miles ago.

I am going to replace upper/lower rad as well as all the Timing belt tensioner bearings, t-stat etc.

Then, I wonder if it is good time to replace radiator.

There is no visual sign of leak/damage on the radiator itself.
Concern is, "WHAT IF", the inner tranny cooler line is already damaged.
No overheating sign or any thing, but, car has been running a little hot. and tranny has shifted a little slow...

Is it going to be safe bet to replace radiator at 138k miles (or 12years old). ?
Or maybe my question is, how much denso OEM rad will last without tranny cooler issue?

Or am I just destroying quality OEM radiator if I replace with aftermarket?

If I am going to replace, it will be Koyo radiator. However, I know that the OEM denso is still much better quality than Koyo radiator. So, I am in a little dillema in between "taking a chance with OEM denso original rad" or just simply replacing with aftermarket Koyo radiator...

Or am I too paranoid??

Thank you.

eddieleephd

Radiator is most likely not the prob it would be the thermostat or coolant.
replace these and see "use OEM coolant because of all of the aluminium and corrosion",
no radiators are not common replacement parts unless they leak.
blow air backwards through the radiator to remove bugs and debris just don't get too close or too high of pressure you can mess up the fins!
Remember to flush the coolant line!!!!!!
heater core and trans are included

Ron Helmuth

Talk to auto tranny guys only regarding this. eddie above and I are manny trannys and our radiators are significantly less complicated than yours.

There are several threads about catastrophic failure of the tranny cooler contaminating the coolant. "milk shake" may be the term used in some threads.

As buhundred alludes to-upgrade while you are at it, if you are going to get a quality radiator replacement, get a quality tranny cooler while at it.

Not sure that Toyota improved the design inherent to the noted weakness but OEM could be the easiest fitment. Search a bit more to see what others have done.

Good that you are planning ahead of failure instead of awaiting it. You may even want to consult the service writer at the Yota dealership and see if he steers you toward an OEM replacement or a local radiator shop.

Jin_Chris

Yup!, I already ordered and have Tru-cool 4454. I am planning to completely by-pass the rad internal cooler. In such way, I am sure it can prevent tranny from getting accidental coolant input.

But my dillema now is actually "is it worth to replace radiator regularly to protect cooling system from getting accidental sudden rupture of tranny oil line in/outlet area... I read many of forum members experienced sudden "puddle of oil/coolant" under the car, which actually means car was driving relatively fine even with coolant/oil mixed inside of the system so you never know until radiator actually severely ruptured and spit out all that messy oil/coolant mixture out of the car. Now, although I took out radiator completely and visually checking, there is no sign of any damage "at least" from outside, but how much confident can we be about the "inside of radiator". Is there any good sign of potential rupture that I can "read" from examining outside of rad? Radiator itself look just fine... by just looking at this Denso rad, it looks like it is going to be just fine for another 100k or more... but I know that tranny oil/coolant scenario is not just scenario..

Maybe, my question is, do we know how it looks when radiator is out-to-be-done.... .... hmmm......

jrohland

Rent a fiberscope and take a look inside the radiator.

jrohland

eddieleephd

here if you are worried about these kind of issues I would suggest some thing like this rather than replacing your radiator more often.

http://www.dieselwarden.net/ford/coolfilter1.html

just be sure to change filter regularly to avoid cooling issues!!

also see:
http://www.tefba.com/

BigBallsMcFalls

only neglected coolant change intervals cause radiator/tranny issues...barring accidents


otherwise it is a life long part and won't -just fail-. but some have, and that is luck of the draw....however, they are designed to last

eddieleephd

this does include using the wrong coolant GREEN is not good in our trucks!!!

Jin_Chris

Bad news. I just opened waterpump and unfortunately, I spotted a piece of rust stuck inner wall of waterpump. Now, I believe this implies there is a spot where rust is currently being built up somewhere inside of the system. I do not think this is anywhere from engine block itself then, the only place with higher probability is radiator inner tranny cooler line.

As you just pointed out, coolant is important part of cooling system. Thus, during the entire history of my 4r, it got coolant replaced at 50k miles, 65k miles, 90k miles and now at 135k miles, I just drained coolant and it will shortly receive genuine red toyota coolant. It was not replaced at 30k interval as recommend, but I am sure it is not neglected either. Yet, I just found out this piece of rust crumb inside of waterpump. What is going on?

Tomorrow, I will closely examine the lower block where waterpump was mounted. I shall bring good flash light...

Now, I am shopping around koyo radiator.....

gpcollen1

Check out the last post on this thread by yours truly. I would say yes or at least some sort of inspection. Save alot of time and hassel.

Maybe an aux temp gauge would have caught this right away! Wish I had done it earlier. Don't really know but makes sense...

https://www.yotatech.com/forums/f2/b...cooler-126953/

ESQ

To avoid the strawberry milkshake, bypass the OE tranny cooler in the radiator.

Evilmunkey

I would say inspect the current radiator, also have you done regular coolant changes/flushes if not then there are harmful deposits in your current setup and then i would still say inspect and then your possibilities to change and maybe upgrade to a better radiator w/ external tranny cooler.

wjwerdna

I would have replaced mine ahead of time if I could have, mine failed at 105-110k with proper maintenance, change intervals, and toyota red coolant. Would have been nicer to replace at will, instead of with overnighted parts, and last-minute plans/labor... Or would have at least just bypassed the stock cooler. Then again, on mine, it failed at the connection between inner cooler and inner of radiator, leading to the fitting just coming off the radiator anyway, which made it impossible to even bypass

desertcamper67

When a truck is new to me, there are a few things I 'like to take care of'. I really like to have a new radiator in my trucks. I have had a '84 and 2 '85's so I am into older trucks. That being said, it gives me piece of mind the get a new shiny radiator in there as soon as practical. I don't know of any practical way to check out a radiator other than obvoiusly visually looking at it or by weighing it. A clogged radiator will weigh more empty than a brand new one will.
I have have several aftermarket radiators with little problems. Only had one fail. It was from Napa and it peeled open like a banana. I had AAA tow it about 5 miles to Napa and replaced it in their parking lot with their tools I borrowed.
Its very easy work and well worth the piece of mind.

wjwerdna

agreed, I've replaced the radiator in the last three vehicles I have owned!