Cleaned EGR valve, not sure if full circuit is needed. 111k miles

Excellent pictures of the cooler. Again, worth noting this is at 111k miles. Can’t imagine any “cooling” took place with that. And only pinholes of flow left. It’s patently obvious Toyota rushed that nonsense to market without testing.

 

Escalate to lye (sodium hydroxide) solution? Hopefully available in the States, say on Amazon. We got some a few years back for soap making, on Amazon.ca. I noticed it's oddly missing from grocery/hardware store shelves. Apparently used in meth production.

If you're not doing this: most expedient is to cork one end of the cooler, then only about a cup of solution is needed. A bare wire run through the fins may expedite the solution's ability to penetrate.

Whatever solution is being used, I've found a one hour soak, then rinse and repeat, to be most effective, just judging from the amount of foaming reaction. It tends to be quite active at first, then subside.

Stumbled on this US lye source:

Online Store

 

You wasted 12 hours.
Oven cleaner. 30 minutes.. Pressure washer.
Repeat if needed....

 

If lye/sodium hydroxide/oven cleaner is used, follow up rinses should be made using very hot, near boiling water.

The sodium hydroxide and hot water converts the oils to a soap, which is then dissolvable in water. This should be much easier to blast through with the pressure washer.

If the sodium hydroxide isn't penetrating into the channels, you might need to drive a stiff, thin wire through as many channels as you can access. You won't be able to get at them all, due to the bends in the cooler inlet/outlet.

SM-G781V ?

 

Regarding the last picture of the cooler. No, that is not good enough. It should be very clean with all visible channels clear.

SM-G781V ?

 

I think this was when I said good enough. There's still a little...


Oven cleaner will do in a pinch; it's basically lye solution. Maybe get several bottles, cork the bottom:

pour it in, and watch the bubbles:

 

Then, after letting the drain cleaner soak in the plugged EGR cooler, pour it out down the drain running copious amounts of water. Then leave the cooler plugged and pour in very hot water and dump it, again using lots of water to dilute the waste down the drain. Rinse and repeat till the water coming out is clear/clean.

You will have to repeat the soaks with drain cleaner multiple times for a cooler as clogged as yours is/was.

SM-G781V ?

 

At least with oxi, I let it soak about an hour, based on it's behavior. After pouring in the solution it bubbles vigorously for maybe 20 minutes, then starts to taper off. Then I rinse and repeat. With lye solution it might happen faster, who knows. Basically watch the bubble action, and when it subsides let it "steep" about an equal amount of time, then rinse/repeat.

When you think you're done, check it with a strong light source; it may need a few more sessions. A few more hours can get it from 90% to 98%.

 

The OP has a pressure washer, which I did not.

Maybe only one good soak with drain cleaner or Oxy Clean will do, followed by rinsing out as outlined above. Then, when you have all of the strong stuff rinsed out, hit it again with the pressure washer.

SM-G781V ?

 

I believe Mendel mixes his oxiclean mixture using near boiling hot water to help it's cleaning effectiveness.

SM-G781V ?

 

Work smarter, not harder.

Do you use carb cleaner? Brake Cleaner? Harsh chemicals.....
You'd have everything back together already if you had used oven cleaner.
You can use just a garnen hose with the strongest and narrowist stream you can apply.

 

I use a saturated solution, using hot tap water (hot water tank set about the usual) and powdered Oxi. To achieve saturation I simply put in a bit more Oxi than can dissolve.

Definitely cork the cooler; it’s way too wasteful doing a bucketful. Corked, it only takes about a cup to fill. Let it work about an hour, rinse and repeat, with fresh solution.

Worth noting: I’ve cleaned ours twice, and the cars only just passed 100k. Kilometres…

if you’re hitting the wall I’d definitely escalate to lye solution, with appropriate caution. In lieu of lye I’d think a few bottles of oven cleaner would suffice. Don’t spritz, just pour.

maybe regs are different in the states? Screen grab from Amazon.ca:

 

As dirty as your cooler is (was), you'll have to work harder and longer to clean it.
When it's not really dirty or clogged, oxy and the other stuff are good enough.
If you catch it early, just the pressure washer is enough to clear it.

Spraying with oven cleaner, which is designed to clear baked on carbon, it will eat it,
and dissolve it so you can wipe it, or spray it away. Since it has a lot of layers to go through,
it will take a few times to get completely through it.

That's why I will spray it in from both ends, and when the foam settles, I spray again, and again, and again, etc.
Then clean it out with the pressure washer. You can get them for under $100.

If time isn't a factor, because you have a spare one, use the slow stuff. Because you can let it soak for months.
White vinegar will also work. Whatever you use, you WILL have harsh aftermath. You're cleaning out burnt
gas and oil....

I'll bet that NO ONE disposes of that as hazardess material do they? NO!