Best way to clean EGR

Going back to the first car with EGR that I ever worked on, a 1979, I've never known any not to become carbon collectors. Just the nature of the beast. That one needed reaming yearly, at least.

I'm grateful that this one clogs over more like a decade, and has a monitor self-test letting you keep tabs on how it's doing.

 

I guess it never hurts to state the obvious, I just figured it was common sense around these parts that holding the EGR cooler with one hand and the pressure washer in the other is not a good idea.

 

Knowing it's not a good idea is one thing, knowing exactly how good an idea it isn't might be even better.

I already kind of knew it wasn't a good idea, but the part about 30% of pressure injection injuries leading to eventual amputation was something I hadn't stumbled on until I looked it up for #16.

Might have an effect on how much I feel like cutting corners some day when I'm in a hurry.

 

That is an important point. Injection injuries can be very dangerous. We are talking 2500ish PSI tearing skin and injecting water and bacteria into the wound.

When I did mine I, clamped the EGR cooler unit in a portable vice. I wore leather work gloves and wrapped a wet towel around the work, and held the nozzle in the EGR cooler with my gloved hand on the wet towel while my helper ran the pressure washer.

All in all the job was hard only due to lack of easy EGR cooler access space. I would think as a service item it could be placed better.

 

NaOH has no effect on carbon but it does dissolve oil

 

It doesn't really dissolve oil, it chemically alters it to a soap, which is soluble in hot water. That's why it is recommended to flush your drain with hot water after treating it with NaOH containing drain cleaner. The hot water dissolves the converted oils and grease better than cold water.

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The time will depend on how long you have to struggle with what I call the "nasty nut." I fount that a deep well 12mm socket and an extra short extension has about the right reach, but it's still hit or miss on landing the socket on the nut since it's impossible to see and reach at the same time. All you have to do is break it loos with the socket. Then spin it off with your fingers. Well, finger, actually. After having done it a few time, I have it down to a couple hours. First time was more like four hours.

Both my hands are always on the wand. The cooler is clamped with vice grips to a pallet leaning on a chain link fence. Treat that pressure washer like a firearm.

Purple power is what we use. And a pressure washer. I can usually clean about a dozen coolers and manifolds in 3-4 hours.

So therefore, not a problem with the pipe or cooler. Just don't use it with the valve fitting or the intake manifold (brass threaded inserts). But then, they don't need anything like that anyway. I use carb cleaner on the manifold ports.

Can't see where clogged EGR ports have anything to do with piston rings.

 

Good point. But I think it's easier to remove those two rear studs than that nasty one while the cooler is in place. After you get the cooler out, it's easier to remove the nasty stud and then pre-install the rear studs. One time (and only one time so far), one of the rear studs came out with the nut. I almost did a little happy dance.

 

@jerrymildred , being pro, I think you’re obligated to reassemble the EGR with all its fasteners, including the lower cooler bracket connection. DIY’ing, I took that lower nut and stud off, and left it off. But appreciate its second-guessing the engineers who designed it.

also, I agree about not seeing a connection between revised piston rings and less EGR clogging. I think the theory is that engine oil burning is clogging the EGR. There may be a minor increase but I doubt the 2015’s (with higher tension rings) are immune.

FWIW my 2010 has no oil consumption still, at 94k kms, but the EGR was getting significant carbon build up when I did cleaning, around 70k. I think it’s the EGR design that’s primarily responsible, and the 4th gen revisions bear this out.

agree too: caustic cleaners are good for the cooler, but overkill for the rest, and react with their metals.

 

I just did it on my 2010 Prius and it took me about 12 hours, but I'm a noob. I've done spark plugs, coolant exchange, basic simple jobs. This one was a royal PIA because of the back bracket and the impossible nut everyone here has mentioned. There is essentially no room back there and you must have the proper tools or it's not happening.

 

if you can get only one finger on it, how do you start it back on without high risk of dropping it? How difficult is it to retrieve if dropped?
Thanks!

 

I'm sure I would be if I worked for a Toyota dealership. Well, I think I would be. Actually, trying to put that nut back on would take so much time, I don't think any customer would want to pay the labor rate for something really doesn't do anything. Having done it yourself, you probably have observed that the cooler is just as solidly mounted without the nut as with it. It has the two at the rear flange, the upper bracket, and then bolted to the valve assembly which is also bolted to the head, and then the pipe that's bolted to the manifold. No one has ever come back with a complaint.

That's a good point. I was thinking of the clogged EGR impacting the rings.

It often lands in the catch pan we put under the engine to catch the coolant dribbles. As for putting it back on, I'm not sure it's possible without major disassembly. Although, a magnetic 12mm socket that's exactly the right depth might do it.

If someone comes up with a feasible way to put that nut back on, I'm all ears ... errr ... eyes in this case.

 

During dissemble, I took off the nut from hell. And removed the valve first, then the cooler. But during reassembly I removed the exhaust studs and assembled it as a unit.

 

Put a dab of grease in the socket? Messy though.

mine resides in a box with a few other Prius bits, labelled.

 

Why do you care if you drop the nut? You're not reusing it.....

 

Painter's tape will also work to hold a nut. I've used it with spark plug sockets that have lost their grip.

 

Aftermarket should sell a magnetic nut. It would be worth the 5 bucks!

 

Magnetize the nut you've got?