Never heard of HD Auto Kool radiators. Cheap radiators are one reason
for early failures.

- You also need to make sure the system is free of air. Hot stream can
speed the cracking of the plastic-equipped top tank (not in the case
of 4Runner, it's all copper for the 2.4L).
- Also use approved coolant (Toyota Red with distilled water) every 2
years to fight corrosion. Toyota Pink stinks BTW.
- Blown headgasket (over pressure) isn't helpful either.
- Make sure the radiator cap is changed with the radiator and has a
spring-loaded vacuum return valve instead of a hang-loose plastic
valve to hlpe keep air out.
- Use Proliance, Koyo, or OEM Denso radiator. Some carry a lifetime
warranty and is cheaper than dealer part.
- You should expect *at least* 100,000 miles out of one. But 1mg/cm^2/
week corrosion rate happens to ALL radiators, so these things WON'T
last forever. .
- Bad grounding causes electrical current to flow through and lead to
electrolysis corrosion. So check ground straps.
- Prefer spring clamps (almost last forever) over worm-gear clamps.
- loca NAPA store offers lifetime warranty on Proliance (Modine),
other places differ

- PROLIANCE Part # 432273 $166.79 on www.rockauto.com + shipping for
2.4L 4Runner
- KOYO Part # 1640035360 $115.89

Hope this helps.

 When they were all Copper and Brass for the cores, headers and
tanks, they'd go 15 years plus with a rodding-out every three to five
years at a good radiator shop. Then either a tank or some tubes in the
core would go bad, and you'd replace the whole thing - or just the
core, or just a tank if the radiator shop had a good used one.

 Nowadays with the Aluminum cores and crimped-on plastic tanks, they
are essentially selling "Disposable" radiators.  You can't take them
apart for service - because they often hold long pressure and not
crack long enough to test good on the bench at the shop, then fail
after you put some miles on the car.

 Yes with the plastic tanks, since the stresses are concentrated
along the seams, and at the 'fingers' that clamp the tank to the core
and it's gasket.  And Aluminum is horrible at repeated flexing, if
they have to bend the radiator tank header 'fingers' to crimp it
together odds are it's going to crack if bent to open and bent back to
re-seal.  Even if they try to anneal the metal with a torch.

 You can still get all copper radiators for many cars, but you will
pay a premium for it.  And I'll bet a rather stiff one considering the
price of copper has gone to insane levels (between the Beijing Olympic
Games and the Three Gorges Dam mega-projects)  and the world-wide RoHS
push to eliminate all lead (solder!) from out lives.

 Get another aluminum core radiator unless you plan to keep the car
another 10 years plus.  But there are vast quality differences
betweeen the "No-Name stuff out of the third world, and the "Name
Brand" where you will be able to find the company in 4 years should
you need to get a warranty claim handled.

 Note that there has been some consolidation - Modine Radiators are
now Proliance www.pliii.com .  The radiator shop should be able to
present a 'Scorecard' of who owns what brands, and if they are good
over the long haul.  (I'm an electrician, another industry where you
need an updated scorecard to track who owns what.)

 --<< Bruce >>--