Information on EGR system and intake Manifold Cleaning

I read that over several times, then opted to fully torque each sub-assembly, from the inside outwards. I understand the rationale, but think at least one of the connections becomes hard to get at, with the sequence they propose. Maybe even impossible? Not totally sure though.

I figured to do my technique, and resort to loosening/retorquing only if misalignment became apparent.

Here it is:

 

Oven cleaner, pressure washer. Those are the best, easiest, and fastest ways too clean it out.
Just spray the oven cleaner in from both sides, wait a few second for it to setting in and spray
again. You'll have to do it several times. Then let it sit for 30 minutes or so and spray out with
the pressure washer. Watch your eyes when you spray!

 

See my post #7. In particular the second link in my signature describes the chemicals and technique I used on the cooler.

I think aforementioned oven cleaner and pressure washer are equally effective, and faster, but if you're in no rush, and lack a pressure washer: "Oxi-Clean Versatile Stain Remover" solutions are something you can do solely in a laundry sink. Again, 2nd link in signature.

Petroleum solvent cleaning of the cooler is not that effective, and leaves you with a toxic mess. If you're wondering what to do with left-over solvent, pouring it over (clean/new, lol) kitty litter in a tray, and setting it outside in a sheltered location to vapourize for a few days works. Stir occasionally. When it's dry, bag and put out with garbage.

 

It's very slow going here, gathering good data on how to calibrate people's subjective impressions of "how clogged" a cooler is, versus actual measurements of flow, because we have a lot more posts giving one or the other and not very many giving both.

The monitor test done by the car is an actual test: if the manifold pressure went up by 18 kPa when the EGR valve was opened, that flow wasn't a mirage.

Subjective impressions are probably pretty good at both extremes: if someone's cooler looks mirror-clean inside, or like a solid cake, there's probably not much room for error. I shake my head more when people post something like "I looked at my cooler and it's 90% clogged"; it's not just that 10 different people may have 10 different ideas of what "90% clogged" looks like, but also that we still haven't got nearly enough data to be able to say which of the 10 was closest to right.

 

I did oven cleaner and boiling water. It only took 2-3 times and i didnt have to go to the car-wash for a pressure wash. Cover the other hole with something like plastic, spray the oven cleaner and let it sit for 10-15. Then remove the cover and dump the boiling water in there. Watch all the carbon go down the drain!

 

The smaller of the two holes on the cooler is roughly 21 mm ID; I scored some suitable stoppers on Amazon, very convenient.

 

Ahh, Toyota engineering at its finest…

excellent pics.

 

Put the oven clean in BOTH ends. Spray and wait 15 seconds or so and spray again.
It will keep foaming. After it's soaked in, let it sit for 30 minutes, at least.
Then pressure wash it. You can get them for $100 or less if you don't have one.
And you can use them for other things that need cleaning.
Since yours is pretty clogged, it will probably take a few times.
You might have to get a bicycle spoke, or other firm wire to press through the carbon.
Just try and be patient, and clean clean clean!

 

It can be cleaned till the carbon is gone, the interior looks like the day it was made. Then you’ll definely see light coming through.

That said, with your carbon accumulation it’ll be tough to get there. A thin wire worked through will help any chemical process, allow it to work along the entire length, somewhat akin to a pilot hole.

Try the alkaline/caustic route, either oven cleaner (more drastic) , or Oxi-Clean concentrated solution (see second link in my signature).

A suitably sized stopper will help, ensure whatever solution sits in there. For me, albeit with very low miles, about 5~6 hour long soaks with concentrated/hot oxi solution had it like-new.

I appreciate +200k carbon is a different beast.

If you look closely at the attached picture, you'll see there's still a patina of carbon here and there, but pretty dang close. A couple of zones flagged in this screen-grab:

 

If you can find a rubber stopper that fits in one end. You can fill it with liquid drain cleaner, not the gel, at full strength. It is basically (pun intended) the same caustic chemical as oven cleaner. I found foaming oven cleaner spray penetrated only the first inch or so on a clogged EGR cooler.

I had to chuck a wire into my drill and go at the passages as well, just to be able the liquid drain cleaner to get in there to do its thing. Even so, due to the offset angles, you can only reach the passages in the middle.

Took me several days of soaks, rinse with near boiling hot water, repeat.

Good thing I bought a spare cooler pre-clean it.

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The pressure cleaner will clear it out unless it's burned in "coal".
The oven cleaner will eat it's way through, that's what it does.
Drain cleaner will probably work pretty much the same.

No need for boiling water though, because the exhaust is 1500 + degrees and water
boild 212 degrees....

 

You can buy sodium hydroxide (main ingredient in oven cleaner, drain clearer) on Amazon. It’s an essential ingredient in soap making, so readily available. It’s no longer available at hardware stores local to me, apparently a precursor to meth?

 

The hot water is to dissolve the "soap" the sodium hydroxide converted the hydrocarbons/oil into. That's why the instructions in drain cleaners always say to flush with hot water after treating the drain/pipes with drain cleaner (lye, as in soap making).

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which oven cleaner are you using? You need to use the heavy-duty easy off one. My EGR looked exactly like yours in your pic. Badly clogged. And i was able to completely clean it with this oven cleaner and boiling water. I was able to see through it clean and clear. Use a combination of carb cleaners or brake cleaners as well. Dissolve that stubborn carbon!

 

Interesting: this is a screen grab from Amazon.ca, in CDN $'s:



US Amazon site I'm drawing a blank for similar, different reg's I guess. We've got a bottle, this stuff or very similar, kicking around, from a soap making notion that stalled...

BTW, I would reserve used of anything caustic to just the cooler, nothing aluminum, or the intake manifold with it's non-stainless metal embeds.

 

Looks good to me. (thumbsup)

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Using a thinner, more flexible wire, I got it through every passage, even the corners. I didn't think something as thick as a bicycle spoke (assuming #14 gauge) could get through at all.