EGR Deposits and Intake Manifold Cleaning

Used to be death and taxes. Now you can add Prius EGR clogging, lol.

I suspect there isn't any driving style, gas choice or whatever that'll prevent it. Really wish Toyota would own up to this lame duck.

 

1. Don't know the answer to this question but my understanding is the "updated" IM is to address the cold start knock issue. Since Toyota doesn't acknowledge the EGR issues, I doubt they'll suggest the newer IM will fix the EGR port carbon clogging. My opinion would be the EGR port will still clog in the newer IM due to flawed design of the liquid cooled EGR itself.

2. Don't think we've conducted a poll but since Priuschat is a fairly small community, the number of reports here suggest this IS a thing.

3. I haven't paid close attention to mileage reports. Mine was at 100k on the button when I found it annoying enough to tear it apart. At 118k now, it's still running great but I will report when it surfaces again.

4. With full disclosure to this being strictly my opinion, I think no. I feel the EGR design is flawed by either over-cooling, too restrictive passages in the EGR adapter or a combination of both. Having seen the port design in the IM up close and personal, I don't think the problem is with the IM. I'm also not convinced the updated IM solves the cold start knock, but that's another topic...

5. If you enjoy DIY mechanics, sure. Otherwise, may as well just wait for symptoms which may or may not develop. Myself and others here have reported good results with only IM and EGR pipe cleaning with symptoms presenting without CEL. Only one that I'm aware of reported P0401 and heavy EGR valve/radiator clogging. When I had mine apart, it was clogged heavily through the IM and into the IM side of the EGR pipe. The EGR valve side of the pipe and what I could see into the EGR valve itself were suprisingly clean. Thus my theory that P0401 only relates to EGR valve/adapter clogging itself. I won't pull apart that nightmare until IM port cleaning doesn't fix symptoms or I get P0401.

As a reasonably capable DIY mechanic, I don't view this as a serious issue, but it is one I feel Toyota should own. Perhaps as Gen 3's age we'll see a TSB. For the typical owner without mechanical ability, it could lead to serious frustration, not to mention serious fleecing.

 

i would love to see a poll. i feel like there are too many, but not that many.

 

Similar to m.wynn's experience, the CEL for my EGR valve lit up at 95k. I've only used quality fuel and fuel injector cleaner, so I don't think it can be avoided. Yes, it's annoying, but compared to more serious design flaws, it's far from the worst.

 

Just finished a $1500 cost journey on my 2011 with 240k on it. First dealer changed EGR and cooler and said they cleaned the IM. The result was even a worse problem. Driveline shudder was 3 times worse after this change. Second dealer pointed out that the first dealer should have also replaced the IM. Supposed to pick up the car next week with the IM replaced. Sure hope it's good for another 200k.

 

why was it worse? i'm trying to make sense of that.

 

And if the intake manifold was properly cleaned??

Maybe they clogged something worse?

 

I am Leary of solvents. You use the wrong one and instead of loosening it makes it more difficult .

An air flow test afterwards would confirm the IM is flowing air well.

Pulling an intake manifold tomorrow and we'll see the condition. Maybe even have a video of it.

 

You can easily remove the EGR pipe, which runs between the EGR out and the intake manifold. NutzAboutBolts has a video. Very simple. This should give you an idea of your EGR's condition. If it has only fine, tan deposits, then there is little to worry about, IMO. If it has black, oily, sooty, gritty goop inside, then your EGR needs a clean out. The biggest cause of this clogging is piston ring failure, of course.

With 113,000 miles, I've had no difficulty with the EGR or anything else. I'm thinking of taking the EGR and intake manifold apart for a preventative cleaning. I'm curious to see if there's anything to take out. The EGR pipe cleaning removed a little bit of hard, ash-like soot, but I think there's no way that cleaning it out helped my car. I just cleaned it because I'd removed it.

 

I have the intake manifold removal procedure. Can you post the EGR and EGR removal procedure?

 

Here's the post from the weekend work at @m.wynn 's place (at least how we went about it anyway):

My Prius is down 4 quarts of oil 9000 miles after oil change

 

When I first took off the MAP (Manifold Absolute Pressure) Sensor (pushes on, just below and to right of the throttle body) it was awash in oil. It had a bit of caked-on black bits. I've dipped it's business end in 99% isopropyl alcohol and gently swabbed with a q-tip.

Hopefully ok; I've not noticed any strange surging, hesitation off-idle, symptoms of a failing sensor. The part number is 89421-52010, and the price is (gulp) in the $200's, apart from some E-Bay sellers for around $20~35, and I'd wonder if the latter really are genuine and/or new?

 

I think a good inticator to seeing if you need to clean your intake manifold is just take off the air filter assembly so you have access to the throttle body and gently push open your throttle body and look at the pool of oil directly below it. I would wager that everyone with 90k and above is going to have a large pool of oil directly below the throttle body. If you have the oil then you have a intake manifold that needs cleaning.

 

I think a good indicator to seeing if you need to clean your intake manifold is just take off the air filter assembly so you have access to the throttle body and gently push open your throttle body and with a flashlight look at the pool of oil directly below it. I would wager that everyone with 90k and above is going to have a large pool of oil directly below the throttle body. If you have the oil then you have a intake manifold that needs cleaning and of course a dirty EGR pipe and cooler.

 

I found the startup engine death rattle at 73k miles. Opened her up and found a pool of oil bathing MAP sensor like you say. I then cleaned intake manifold, entire EGR system from Intake to EGR cooler, PCV valve. Spark plugs had large carbon deposits so I replaced them. I then installed a PCV catch can. Problem went away - engine sounds like a mouse and it's getting fantastic gas mileage.

Pixel XL ?

 

That oil accumulation starts pretty early. Sources? The PCV valve hose for sure. I've resolved that (knock on wood) with oil catch can, but I wonder if more oil, hopefully not as much, is getting kicked out of the intake ports? I saw some evidence of that on a second look.

Also, any suggestions for MAP sensor cleaner? Maybe MAF cleaner?

 

An electronic contact cleaner should work. MAF cleaner works.

Pixel XL ?