EGR & Intake Manifold Clean Results

Sounds like you've been running with "compromised" EGR for some time, which leads to elevated combustion chamber temps, and that's likely what's killing head gaskets.

 

but there's no coolant loss? that's what is messing with my head. if i was losing coolant, then it would be a no-brainer.

 

Then I would not suspect the EGR system. Do you have techstream that will tell you which cyclinder(s) are misfiring? If so then you can switch coilpacks to the non-misfiring cylinder.

 

Any signs of rodent damage?

Did this start out of the blue?

If all cylinders are doing this, are all connections tight?

 

i do not. have a bluetooth OBC2 and Dr Prius app that says it's 2 and 4. i just swapped the coils and I got the same issues. I put 2 in 1 and 4 in 3, and i still got the 0302 and 0304 code

none that i can see.

yes, a couple weeks ago. started shuddering at startup and started to throw codes.

just double checked, and yes they appear to be tight

 

Ok, this car must have gremlins. Last night I was getting the codes I took a screenshot of. I don’t know how it threw two misfire codes for cylinders 2 and 4, but whatever. This code persisted even when I swapped the ignition coils.

I said forget it last night and went to bed, planning on dealing with it today. This morning I get in, and it fired right up. No stumbling, and no codes at all.

yay?

 

No codes? I see codes in the app screenshot.

 

I’ve been burnt once. I’ve thrown a lot of new parts but my engine was bad. So please do compression or leak down test first as suggested. Or change the coils to different ones to see if codes follow the coils.

 

Don't take the cylinder-specific codes too literally. They're a suggestion but not a diagnosis. The ECM tries to assign blame to specific cylinders(*) to be helpful, but this becomes confusing when the problem isn't actually specific to one cylinder. Which in this case the P0300 code seems to be spelling out.

(*) The ECM keeps count of certain errors, and when a count crosses a threshold it throws a code for that specific cylinder. Doesn't always mean the problem is localized to that cylinder though.

 

That was last night. I didn’t take a screenshot this morning when there were no codes. Sorry if that wasn’t clear

 

I’ve swapped the coils, and the codes stayed the same. But today, I got no codes and it started right up.

 

I pulled the intake manifold and EGR pipe off today after I changed the spark plugs on my 2011 with 126,536 Miles. Tomorrow I'll pull the EGR valve and cooler.

I hit the throttle body, intake manifold, and EGR pipe with brake cleaner quickly. Then wiped everything down with towels and a brush. Soaked the pipe and intake manifold in oxy clean.

I think I was told somewhere not to use brake cleaner on the throttle body, so I stopped almost immediately after spraying it, is there any truth to that?

Pipe before:


Pipe currently (still soaking):


Manifold before any cleaning:


Soaking:

After 1st soak:

 

Is that an Oxi-Clean soak? Try to very thoroughly rinse away all Oxi residue, then maybe hit any of of the bolt through passages or threaded inserts with a little brake cleaner. When I (very recently) removed my intake manifold about 2 years since the last cleaning, where I used Oxi soaks, there was one or two bolts with a white crusty build-up, think it was residual Oxi reacting with the bolt metal.

I cleaned everything, sprayed with brake cleaner, brushed on a little anti-seize, hopefully that'll resolve it, or at least keep it in check.

For the throttle body, spray a little carb cleaner on a cloth, then go over the throttle body barrel and blade. Take your time, it's a bit of a handful, holding the blade open and wiping.

Did you leave the coolant lines attached to the throttle body; it is possible: just lift off the throttle body and tie up somewhere, out of the way.

 

Yes. Thanks for the tip, I'll rinse it the best I can.

I clamped the lines and pulled the throttle body all the way out.

Edit: I just dumped the 2nd oxi-clean soak and switched to a dish soap soak.

 

After rinse, maybe some sort of compressed air on any of the metal bits, then a shot of brake cleaner.

 

A soak or two of 30-40% mixture of Super Clean or Purple Power equivalent and water takes it to the next level clean after the Oxi soaks stop being effective.

Try using solid rubber stoppers to plug up some of the ports and a hockey puck with c-clamp to block the throttle body opening.

Some nylon pipe brushes help to get some of the junk loosened up in those small EGR channels at the intake interface.

I had some old clear plastic which I put over the intake interface ports and drilled 5 holes in it where the IM bolt holes are. Leaving the IM gasket in place, I then sandwiched that plastic between the gasket and an old 2x4 using some wood screws and washers which ensured a perfect seal. That and the stoppers allowed the mixture to be agitated within that end of the IM and was key to getting it spotless.

This helped completely clear 100% of that oil soaked soot gunk that hangs around inside the EGR channel and lifted everything the Oxi soaks left. It took my intake from ok to brand new looking.


iPad ?

 

With the proliferation of steel drinking straws, there's brushes for cleaning them that are good for those small ID EGR channels. I got these:

Straw Brushes - Lee Valley Tools

One for the house; one for the garage.

When I oxi soaked mine I had it with the 4 intake ports facing up, the throttle body end down, and propped up a bit (in the laundry sink). IIRC I only needed to use one small stopper for that, at the PCV inlet.

FWIW, this last time around, I just did a quick job with brake cleaner, and I think that was good enough. The interior is somewhat rough plastic, and it seems like it never gets perfectly clean. Also, I don't like the way the oxi residue was acting on connection bolts. And it is very time consuming.

Oxi poured in through the EGR pipe (with a funnel). Note the throttle body end propped up a bit:



Also, do yourself a favour and remove the 2 throttle body hold-down studs (E6 Torx). They could get bent, and if removed you will not have oxi solution working it's way into the connection.

 

I'll use some of this degreaser tomorrow, but its already looking pretty good. The recommended water mix is 50:1, I'll probably try 15:1.

I'm going to grab some more brushes tomorrow but so far I'm using a toothbrush like you have in that picture.

Like you said, I dont think these need to be spotless and I'm not going to go overboard on it.

 

I pulled off the EGR cooler and valve off and did the cleaning today. I didn't find the notorious difficult nut to be as difficult as I expected.

To clean the EGR cooler I first hit it with some brake cleaner then I mixed 2 scoops of Oxi-Clean with 2 gallons of hot tap water in a standard 5 gallon bucket and let the cooler soak for an hour, I did this twice and it started to looked pretty good already. Then I plugged up one end of the cooler and put degreaser in the other and let that sit for about 10 minutes. Fired up the pressure washer and the diesel burner, once it got steaming hot I pressed washed it from both sides.

Before:

After:



The CAR has 126k BUT the engine might have different mileage. I bought this used with 70k miles and it's a 2011 carfax was clean and no mention of major engine work. Today I noticed (9/12 309) was written in blue paint pen on the motor. What could this mean? My first thought was possible junkyard engine and that was the date they pulled it and verified functionality?