I recently discovered that my radiator is leaking. (See pic)
My 4Runner is 4.0 V6 with about 160k miles on it.
The leak isn't too bad. I noticed a few drops of pink liquid in the garage and started investigating. Overflow reservoir was still between low and high level. And it seems to drip only when pressurized. So I have some time to plan things out and gather parts.

So planning to replace it with a new Denso radiator from RockAuto. While in there, I at least plan to replace upper & lower radiator hose, radiator cap, thermostat and serpentine belt.

Any other items I should replace while I am in there?
Some list I can think of are:
Water pump
Idler pullies (3 of them)
Tensioner (just tensioner pulley or whole tensioner assembly?)
Alternator (Looks like alternator bolts need to be removed to replace tensioner assembly anyway)

Or should I just leave them alone, why fix it if it ain't broke?

What is average life time of the Water pump for this engine? For those who has more than 200k miles, have you ever replaced water pump? Was it due to failure or preventative maintenance?

What about Alternator? What is average life time? An alternator failure can leave me and my family stranded, and I don't want that to happen.

I plan to do all the work myself, so would like to get as much done as possible when it's taken apart and I am in there, but at the same time don't want to go overboard with it.

Attached Images

 

I'm kind of embarrassed to say I have the original water pump at 237k miles

Why embarrassed? You should be Proud!
How about alternator?

Well the v8 guys are replacing their WPs every 90k mile when they do the timing belt lol. I probably should replace it sooner rather than later as PM, but don't have any issues at the moment. Radiator was original until about 215k when I blew a hole in it with a 4" thick ice chunk off roading

Alternator I am on the 2nd. Lost the 1st at about 190k. Battery light came on as I was entereing the parking lot for an errand. I shut it off and went in, did what I needed to do, came out restarted fine w/ battery light, and I didn't make it two miles before the battery depleted lol. Replaced by a shop before I learned to work on it myself. Probably an auto parts store brand unit

I see. Thanks for the info. That's what I am worried about, and my mileage is getting up there. But whole alternator, radiator, water pump replacement job sounds more like an entire weekend job, where as just the radiator can be done in an afternoon... yeah... I work slow... hehe..

I would certainly think about replacing the stuff with coolant like the WP and hoses. Pass on the alternator and pulleys unless they feel bad. Those are pretty easy to swap. My radiator looks similar at 215k. Maybe in the spring, I'm not losing enough for the miles I drive a week.

At 125k, I did the radiator, hoses, water pump, t-stat, idler and tensioner pulleys, serpentine belt and radiator cap. None of it was leaking or giving any unusual sounds but I've owned this since new and plan on keeping it another 15 years so for the relatively small amount of money for me to DIY, it was well worth the time and effort. And, FWIW, went to the dealer to get the radiator and the parts guy, who I know from years of buying filters and stuff, told me to save a ton of money and order the Denso from Rockauto as it is exactly the same radiator as what comes in the Toyota box. It's amazing how easy it is to do all the front end of the engine stuff when the radiator is out of the car.

I dealt with this very recently and also went with a Denso radiator, Fit perfectly. I also did hoses, thermostat assembly and radiator cap.

You may not have the the rust issues I face in the NE, but my garage also found that the transmission coolant pipes "manifold" was also leaking due to rusted pinhole, so I replaced that as well.

I also got it from Rock auto:
DORMAN 624279 (624-279) Fluid Cooler Line $ 47.79

HTH

I cracked my radiator on the trail in the middle of nowhere solo and the power steering fluid cooler lines. 2010 110,000 miles. Nothing on that belt has had any problems until I caused the power steering pump with no fluid to seize trying to get where a human could find me. I'm just replacing the radiator, condenser, fan belt, steering pump and relocating the steering cooler line. If the alternator is putting out proper voltage it's fine. The others on the belt are fine if no leaks and the pulley turns easily by hand. You can rebuild them also before they start having issues.

I have 168k on my 07 V6. I had a leak from the water bypass hose behind the thermostat. I replaced that and the upper radiator hose. A few days after that repair, my garage floor was covered in coolant. Turned out to be the water pump leaking. I would probably go ahead and replace it.

It's safe to say that if you're doing a radiator job you should certainly be looking at doing a long travel setup front and rear just to make sure you gain a little extra elevation for radiator fill plug... it's the only way I know to properly burp the coolant system after a replacement... ;)

I'm planing on doing the same job on my 4th gen as well and accumulating parts: so far I've got the radiator, the thermostat, the main hoses, the pullies, the water pump. I had to replace the alternator at about 180K, and I'm at 200k now.

I did that radiator job on my 3rd gen several times but have not done it yet on my relatively new (to me) 4th gen. Always did the Denso from Rockauto. I would definitely do the radiator, cap and thermostat. Would also do the upper and lower hose if they have not been done recently. The 3rd gen V6 had a timing belt vs the chain in the 4th gen so the water pump was done with that, It was a different level of complexity than the radiator job. Not sure in the 4th gen.

Just last week I had to replace the radiator and three idler pulleys on my 2003.( 2,4000 miles).
Asking a mechanic as to why the radiator failed he says it is very common. My radiator was leaking at both sides ( 3 and 9 o'clock) due to normal vibrations.
The 6 o'clock idler pulley had just started to make noise. When checked all three pulleys were bad! Another common problem I'm told due to the serpentine belt tension.
The radiator is common and was not expensive to buy on line. Shipping is a killer if not included in the price,mine was included.

I'm at 266k and my water pump is original.