My Radiator

[smokey0066]

Ok so I got paranoid after reading about all the strawberry milk shakes and went out and bought a koyo replacement. After a week of DD my new koyo I decided it was time to open up the old one to see what the fuss was all about.

A little background on my truck. '00 4runner sr5 v6 4wd with 155k on it. I've never serviced the coolant in this truck but it did have water pump replaced at around 45k and a timing belt at 102k so I'm sure there was some fluid replacement and is not the original fill. I've only topped off with green 50/50 which eventually turned the coolant a nasty brown (took awhile to flush out). Enough with the ramble, onto the photos. Keep in mind I took these pictures from my cell phone so they're not the best of quality.

looks like my radiator could have used a bit of cleaning.

Here are some close up shots of the transmission fittings. You can see there is some corrosion on both washers for the fittings.

Time to open up the lower end tank.

Lower end tank removed. The inside actually looked pretty good for never changing the coolant myself. It can really with stand neglect and take abuse.

A little residue, is this some silicate build up from the green mix??

Onto the transmission cooler which is what we're all concerned about anyways right? This actually doesn't look bad at all.

Time to remove the fititngs and see whats going on. You can see there has been some leakage of the coolant around the fittings but nothing horrible. The orings look decent on both fittings.

The lower end tank also has some built up of residue around the holes.

And finally the transmission cooler. It actually looks pretty good from the outside but you can see that corrosion has made its way to the cooler itself behind where the orings are supposed to seal. I think I was on borrowed time.

So I'm really glad I did the swap. Looking at it I probably could've gone another year? or who knows but its a gamble not worth taking for the ~$200 to do the swap and flush. Hope this helps anyone who is on the fence about doing the swap.

 

[Duane]

I am thrilled you have done this as I had asked in other threads what the root cause of the dreaded strawberry milkshake is without ever hearing a reply.

I always wanted to know if the problem was from not changing the coolant and then the failure was corrosion from the coolant side through to the oil.

The radiator internals looked really good on the coolant side. So it looks like the coolant corrodes the fitting until it finds the oil. Is this what you are thinking then?

Would be cool if you can split the oil cooler and see what the internals look like and post up pics.

 

[smokey0066]

I think there is one other post up in the FAQ about this but it was pretty bad. I was curious where mine stood so I took mine apart to share with others.

I don't have any metal cutting tools to properly take the cooler apart but from what I can see it looks to be in good shape. No corrosion, cracks, leaks, stains etc. Very clean except for the join where the it mates to the fittings.

 

[haryv]

rust or corrosion in the radiator is usually a function of electrolysis. If the engine to body ground have high resistance, then the engines ground electrical path will always take the path of least resistance which is usually though the coolant to the radiator. In essence, the coolant acts as the ground wire. This will cause ionic action "corrosion of the inside walls of the engine block" and cause rust issues as we speak.

Radiator coolant is required to be replaced every two years to also keep its lubrication properties up to specs for the pump and some anti corrosion and glycol readings up.