2006 SC430 130k miles.

Top of radiator on back seam had pink dried coolant along most of the back seam.

Upon closer examination, I had a leak around the top part of the bracket which holds the coolant recovery tank . I was not sure about the seams… I cleaned the seam with water and alcohol.

I noticed the crack was about 1.5 inches long. I drained the radiator below the level of the crack. I cleaned are with alcohol and sanded the area in front of each end of the crack. I took a flat blade soldering iron and melted the plastic along the crack just enough to seal the crack. I used a fairly thick application of regular JB weld (not the plastic type} along the crack. Filled the radiator after 24 hrs and drove the car for a week. Then, discovered another leak . See picture with pink line on it, it’s the bracket which attaches the fan shroud . I cleaned the metal seam again as the coolant leaked along the seam. I again sealed the hairline crack along the fan bracket with a solder iron and JB Weld, no leaks for three weeks. The seams remain clean. The issue is the vibration and weight of the coolant tank and fan shroud which has caused these stress cracks. I examined all of the plastic brackets which are part of the plastic radiator top and sanded corners of brackets and added JB weld to those brackets as a preventive procedure to add strength.

So, before you diagnose a leak along seams, you may find it’s a crack above the seams which leaks along the seams …..

 

I would replace the radiator. They are not that expensive. $125 for a Denso on rockauto.

 

1) its a slight hassle to have to deal w the transmission fluid since its a sealed system starting in 2006
2} the leak is due to stress over time, so far, no leaks at the seam
3) several that have replaced the radiator w the Denso have had leaks anyway, the quality is not the same as the original radiator.

I get it, its not that much money,

 

I think your on a slippery slope here mate .
I had similar marks on my radiator and decide to swap it out for a new one , when i pulled of the top and bottom hoses off the radiator inlet and outlet just crumbled away , once that plastic starts to break down its time for a new one .
I would definitely replace it with a new one

 

Thanks for the tip, will monitor it on a regular basis.

 

Proceed with caution. If it was my SC, I certainly wouldn't take it far from home with an iffy radiator. And if it does start to overheat for any reason, stop immediately and tow it home. Overheating an engine results in a plethora of problems down the road.

 

That repair is going to fail only a matter of when.

 

When the plastic fails the first time, it means all of the plastic will fail…replace the radiator…if you don’t it may cost you an engine 😉

 

Alright, you guys were correct...... my crack along the top plastic tank again started to leak, I repaired it a second time and its held up very well.....so, my wife took the SC on a 600 mile trip and when she came back, I checked the radiator, ...... my crack repair did indeed hold up !!! However, an new leak showed up in the commonly found other weak spot under the top of the radiator inlet for the main big hose..... long story not so short.... the engine compartment was sprayed pink (Toyota coolant) , emanating from the underside of the main upper radiator hose over a fair amount of the front of the engine...... I now have the new Denso radiator from Rockauto.com along w new upper and lower hoses, and a qt of World WS Toyota transmission fluid (2006 6speed transmission ) , I am not in a rush, Day one, removed bottom plastic engine cover, clean engine compartment, drain coolant. Day two...get some foam insulation(used along perimeter of the radiator) (I will probably use Home depot foam insulation, better than nothing) (did not come w the Denso radiator) methodically R&R the radiator and hoses..... I've read some of you guys did it all in 2 hrs...eh,,, I will likely take a total of 5 to 6 hrs w clean, up, tarp under the car for transmission fluid mess etc etc..... I plan to take a 2000 mile trip in a couple of weeks and will take this car ONLY if I have driven it a hundred miles to ensure I did not get a Denso radiator pinhole leak like several here have had......so, the moral of the story.....
You guys were right and my attempt to epoxy the initial crack did not make a difference since a new leak surfaced.....

 

Lex,
Your wife was lucky the radiator held up during her trip. You were also lucky that your SC was not overheated.
Radiator is cheap and it’s fairly easy to replace (I just had my mechanic replaced it ).

 

Did you spill some trans fluid or carry it off with the old radiator? how much? Was it difficult to top up?

 

Actually, I just pulled the radiator, left both transmission hoses connected at the radiator and when I tipped the radiator to drain the fluid only a few ounces came out
Update:
OK, I purchase a quart of WS transmission fluid for the transmission line, while the transmission hoses were tied in the upward position on the new radiator, I took a turkey baster and filled the chamber w fluid to just below the smaller hose top level. I then transported the assembled radiator installed it in the car. Then untied each transmission line and quickly uncapped the transmission lines on the engine and inserted the hose. Did not spill more than a few drops . I used just a few ounces.