Information on EGR system and intake Manifold Cleaning

My mechanic wants to inject 'SeaFoam' into a vacuum line.

 

From a vacuum line, 'SeaFoam' will be drawn into the intake, and then into the combustion chambers, where it will be turned into exhaust before it ever reaches the EGR system.

Sometimes neglected when people take on these EGR projects is the value of getting the before-cleaning and after-cleaning EGR flow numbers from the car.

That's (a) the way you'll know how much your effort accomplished, and (b) when you report it on that thread with your car's odometer and driving conditions, contributing to our knowledge of how other people can judge when to jump into the same effort for themselves.

 

Yeah get the flow numbers with tech The dealer types software If you have that and you see you need cleaning I'm telling you man it's much easier on you than farting around with folks that don't know what's happening it's much easier to run by LKQ grab one of these coolers off a car that's easy to get it off of because the front ends off of it grab an intake manifold while you're standing there that's the plastic part that the throttle bodies connected to and you can send the EGR cooler over to your local machine shop who will tank it and when it comes out it will be whistle clean like brand new literally no worries it will be stupid clean and then your intake manifold a couple small brushes and you can blast right through those little holes in the center of your ports at the bottom of the intake won't take but few seconds to run a few brushes through there and pull them out spray all that off and clean it you can do that at the house but the cleaning of the shiny silver EGR intercooler You probably want to get that tanked no brushes no funny business tanked seriously and what they dip heads manifolds and other metal parts in you'll be very happy money well spent 30 bucks maybe then your mechanic can just assemble those clean parts to the car without wasting any time of his pushing brushes and doing things like that You don't want to pay somebody making $75 an hour to push a broom or push a brush That's my logic anyway.

 

Do EGR flow numbers set a code?

My mechanic can only look at the codes, not much else.

The dealership is much less helpful.

 

The codes are based on the test result numbers, but the code only sets when the result gets "bad enough". The nice thing about looking at the number directly is that you can see how "bad" it is (or isn't) before you start, and you can see how much better you made it, and you can do all of this without it ever getting near "bad enough" to trigger the P0401 code.

So, it gives you quantitative information to work with, not just "is it so bad it sets the code already, or not."

It doesn't take a complicated scan tool to show emission monitor results. That's the OBD standard "mode 6". Lots of scan tools and apps can do it, as you can see if you look through that thread I linked for the wide variety of tools people are using to read the info.

 

See first and second links in my signature; first has links to videos, tool list, tips. The second link covers more stuff, in particular what chemicals I used.

If you're on a phone, turn it landscape to see signatures.

What's the miles on yours?

 

The only way to properly clean it is to remove it and manually clean it.

 

18 kPa does not seem strikingly bad. Best we get on a freshly squeaky-cleaned system tends to be around 21 point something. I cleaned mine when it was down to around 10 point something, at 15x,xxx miles.

And yours is at 222k miles? Has it been cleaned before? What kind of driving do you commonly do?

 

I doubt they cleaned the cooler; that doesn't seem to be a common dealer service.

I'm guessing all those 120 mile days played a role in the reading being so good at this point.

 

The number you're showing seems to say you don't really need to clean the cooler yet. Cleaning out the manifold EGR passages might still be wise, though, and is much easier.
I'm getting a similar or slightly better flow number.

 

Clean the intake manifold, throttle body, egr pipe with carb cleaner and brush. Then clean the EGR itself with oven cleaner and boiling water, do it about 2-3 times until you can see through it which means its unclogged.

Also since you’re already there, you might as well change the PCV valve. Your prius would run a lot better.

 

I know what you’re saying. It is a bit of a moon shot: you’ve got the intake bolted to one face, the EGR valve/cooler bolted to anther face of the engine, and the exhaust manifold, on a third face of the engine. And this bent pipe with flanges both ends, bridging between the two. It’s a testament to accuracy how well it all fits.

I torqued the intake manifold, and the EGR components, and then placed the pipe between. With the latter I got all the bolts in, then just snugged them all, and lastly torqued them all. There was ever so slight imperfection, but it all pulled together.

 

The installation section in the repair manual does have a suggested multi-step approach: temporarily snugging valve-to-cooler nuts A and B, then installing the studs, then temporarily snugging 2 nuts (C) and bolt, then torquing A, then torquing nuts B and C and the bolt. (The As, Bs, and Cs are shown in the diagram I haven't pasted here.)

And of course it says "Make sure that all installation surfaces of the EGR valve with cooler assembly are in even contact when tightening the bolts and nuts."