I just replaced the original radiator on my 2000 4WD Limited 3.4L with 230K miles. I am the original owner so I know it had never been replaced. Old radiator was working fine so this was just preventative maintenance. I also replaced the thermostat along with the upper/lower hoses, and flushed out the system.

The new radiator is an OEM Denso part# 16410-AZ011, which I picked up from the dealer for $152.
I thought it would be pretty much the same as the original. Not quite.

Before I get to my gripe, one thing I do like on the new Denso are the hooks on the sides that align up the bolt holes. Made the install so much easier.

So here's my complaint. Why is the petcock half the size of the original and of such low quality. When I loosen it, it wobbles almost like the fitting is off. When I hand tighten it down I feel like it's going to break off in my hand. At one point I just stopped tightening and called it good.

The new radiator does not even have the weep hole below the petcock, where you could blast pressurized water straight down like you could with the stock radiator. You have to carefully loosen it so it starts trickling, and don't dare open it up too much or it'll pop off and you will get soaked. Ask me how I know

There's no middle ground. It's either a slow trickle or full blast straight back.

I thought (for a split second) to maybe drill in a little weep hole. But then common sense prevailed, and to leave well enough alone.


edit: I didn't realize until today that there are more than one OEM radiator to choose from....so this is the "economy" line. If I wanted something closer to factory it would cost much more than I paid.

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Rascals. Still a pretty good radiator though. Luck and enjoy the Runner.

You answered your own question ... you get what you pay for. Although it would be nice if the dealer would let you know there are several options and what differences are, but they probably don't know.

This is a better option than OEM.

Thanks Tim. BTW, I used your flush video, step by step, for reference and it worked great. Next up is changing the 114k, 13yo timing belt and water pump. By your video it looks pretty involved so I will get a shop to partake.

You could easily do the timing belt with the right tools.

You know, I might take you up on that advice. Stay tuned. To note, I rechecked the last CarFax and the dealer notes say the timing belt & water pump were changed at 86K. So not 114K but 144K. So I would say I am a tad overdue!

This was my experience as well. When I ordered the 221-0508 Denso unit labeled as OE from RockAuto, I thought I was getting an OEM quality and style radiator. To me, the new Denso radiator just didn't feel as "solid" as my old original one. I was also disappointed with the drain, as when I opened it up all the way it just blasted everything behind it with coolant and got everywhere. Makes me wonder the true quality of this radiator, and if it's any more prone to the pink milkshake. After running for years with my radiator transmission cooler bypassed and just using my B&M external one, I hooked my transmission cooler back inline with the radiator cooler to further cool my transmission temps while towing. Hoping I didn't make a mistake by doing this.

This is for sure on the list in the future. Thanks, Tim!

I'll agree with Tim, though many years ago (2011?) I had the FSM and not Tim's assistance. A buddy and I followed the take-your-time method with his tools in his garage. Took a while, but we had no problems afterward. Not one. I think we did that at around 125k miles, and I got rid of the truck at 265k.

@ OP, I’ve been running the same radiator (made by Denso, from Toyota) same p/n, with no issues since 2018 (knock on wood). I never even paid attention to the drain valve when swapping units.

I’d be curious to know if you’ve installed an aftermarket trans cooler? That would be a great time to do so when swapping rads.

been running the denso since 2016. ts been fine, But will prob change it out this coming spring for safety sake as some people say every 10 years, some say when it changes color.....sadly some wait till they have a pink milkshake

I ran the denso from rock auto when I bought the 4runner a while ago with a new oem cap. I noticed that after my drive to work it would never build pressure. Tested system, it held 15psi no problem and no leaks. Tested the new cap, same held pressure.

One thing I noticed, when putting the cap on the radiator it didn't have the resistance when turning it. That's when I noticed, squeezing the hose I saw a bit of movement in the overflow bottle. So I bought a new oem cap. Same issue. Measured out the sealing steps in the cap to the sealing steps in the radiator. The radiator ended up being a few hundredths to long vs the cap! So it would never seal the pressure side of the system.

Long story short, I ended up buying the koyo radiator and cap and never looked back.

Confirms in my mind that the Denso "OE" radiator is not nearly the quality of the radiator from the factory.

Another post about the crappy quality of the Denso radiators. I bought a Denso replacement from Rock Auto for my wife’s Acura MDX (purchased it before I installed the Denso radiator on my 4Runner). Finally got around to installing it the other week. Much like the 4Runner version, this Denso radiator just felt flimsy and cheap compared to the factory radiator I took out. Her MDX has a transmission cooler in the radiator just like our 4Runners. After I got everything back together, I noticed a steady drip of transmission fluid every time the engine was running. I tightened the fittings on the radiator, but the leak persisted. So I unscrewed the leaky fitting completely (they’re not the press in type fitting like the OE radiator had) and found the a terrible flare on the compression fitting they used. I cut it off and reflared the fitting, reassembled, and the leaking stopped. This just re-confirms to me the crappy quality of these Denso radiators.