EGR & Intake Manifold Clean Results

Well even though I cleaned the egr circuit twice (126k & 178k) I had some shaking today(188k miles), followed by a P0302 code, and Coolant is an inch or so low. Is this 100% a head gasket failure?

 

P0302 is misfiring cylinder number 2, I think.
The coolant is a bit low, so I would think about head gasket, but by no means would I be for 100% sure.

Besides head gasket I would think about spark plug and spark coil.

By checking the spark plugs and coils, I would look into the cylinders with a boreskope.
If the piston in the cylinder 2 is cleaner as the others, it could be the head gasket. If I had the tools, I would pressurize the coolant tank and look carefully for drops forming slowly in the cylinder 2 (and others) near the head gasket.

If not the above, I would make a leak down test.

This tests should tell you, what it is.

Mat

 

I’d be more inclined to ask if it’s “likely” head gasket failing, and, with:

1. Belated EGR cleaning
2. Cylinder 2 misfire
3. Dropping coolant

my answer would be very likely. And for confirmation: swap coils/plugs between cyl 2 and 4, see if code changes to P0304.

 

I did the first EGR pipe cleaning, throttle body cleaning, and intake manifold removed and cleaned today at 162k miles - pics attached. This is a 2015 Prius 3. It doesn't burn oil, and gets oil changes every 4k miles with Mobil 1 extended range from mile 16. None of the intake manifold ports were blocked, the EGR pipe was unobstructed. The car runs great. I've had the start rattle a couple times, always on extremely cold days - it's never happened since I started garaging the car overnight in the winter time. I believe this issue is tied to temp and internal humidity.

There was a 1/4 cup of oily liquid pooling under the throttle body. I broke a screw on the air-box reassembly. I replaced the PCV valve and was surprised that the original valve still clicked upon shaking. The throttle body was clean.

I appreciate all the tips and tricks posted on this website. I never would have been able to tackle this job without PriusChat.

 

@Michael Wood, what about the EGR cooler? Ours was about 80% blocked at 124K miles on the odometer.

Posted via the PriusChat mobile app.

 

You didn't clean the cooler? Kinda the most important part....
And you pretty much had everything apart....

 

I defaulted to The Car Care Nut on the cooler. The cooler is a part designed to handle exhaust gases. It's likely to be as nasty as the CAT and the exhaust manifold. But unless I'm driving a high risk Prius, or having problems, I'm gonna leave the cooler alone. If I do experience an issue, I'll use The Car Care Nut's putty knife trick to isolate the valve and cooler, and then dig in if it's a sure thing.

 

Oh well, it's your head gasket....
No sence in changing the oil filter when you change the oil...

 

Yeah who knows.

 

It's always a missed opportunity when somebody does one of these cleaning jobs without first reporting their mileage and flow measurement on the thread we have for that. (Once somebody has done the cleaning, it's too late to get the "before" flow result and post that.)

But you've still got the opportunity here to at least get the "before cleaning the cooler" flow value, which should be about as good as a "before any cleaning" value, because the cooler accounts for a lot of the reduction in flow.

Once you have your flow measurement, depending on what it is, it may reinforce your confidence that you don't need to fuss with the cooler just now, or it may give you a nudge to do that sooner. Won't know till you see it.

 

Unless someone can point me to some real definitive evidence, I don't believe a clogged EGR system can cause failure of the head gasket. I think, since it occurs between two cylinders at the water jacket/passages where the width of the gasket is the narrowest, I think it's either a faulty head gasket design (Toyota did revise the gasket in 2013 so that should tell you something) or corrosion of the gasket due to not changing the coolant or using a sub-standard coolant. I can't see combustion temperatures rising that much higher due to no EGR flow to affect the gasket since there's no pinging and the Prius Atkinson cycle engine is so anemic compared to engines out there with turbo chargers, etc. putting out much more horsepower per liter. I'll be glad to be corrected though.

Question: my coolant tank has a B line on it. What does that mean (boiling?)? Also, there's only about 1/2" difference between the full and the low lines. That seems rather close graduations. Should I fill the tank to B?

 

Whatever...........

 

The B line is used only when you are refilling the cooling system when it has been drained or low. There will be some air in it then.

As covered in the repair manual, you fill to the B line, tighten the cap, start the engine, then run it up to temperature and several minutes more. Squeezing and shaking some hoses will help chase the air out. The air ends up delivered back to that reservoir through that upper hose.

When you turn the engine off, the coolant is still hot, and won't give you a good level reading right away, but after you wait for it all to cool down again, it should be right around F. What happened was the coolant from F up to B traded places with the air that was in the system.

So at any normal time, when cool, the level should be at F, and if it's a little low, F is where you top it off to.

Whether B stands for 'burp' or 'bleed', or some other English word that some Japanese-to-English translator happened to be thinking of, doesn't seem to be widely known.

There's not a huge height difference between full and low, but notice that reservoir is rather wide, so a half-inch difference in height is still a decent volume of coolant. And in a shipshape system, none of it should be going anywhere any time soon.

 

I swapped these in for the OEM Phillips style. They're socket head cap screws, M5x16, with a 4mm hex recess in the head, and knurled face around the head. Applied anti-seize when installing.

 

I believe the B line is where you fill to when refilling after draining the system while bleeding air out, etc. Once the air is out keep it between full and low.

Were at 230k on the 13 Prius running high air temps in AZ and were not having the oil burn issues or head gasket issues others in our area seem to experience by following the advice of so many others here on the forum. My son who is a Toyota Master at a high volume dealership in Phoenix area agrees with everything we've done on keeping the EGR and especially EGR cooler clean from the folks here on this forum along with his experience looking at what is going on with the many failed engines he replaces on the gen 3's. That said its not real definitive evidence. We also replaced the ICE electric coolant pump as P/M around 160k as they supposedly lose efficiency over time.

 

It looks like you did an awesome job cleaning, I have to ask was the image 0591.jpg (Head intake ports) really that clean with your regimen or is that after you wiped and cleaned into those ports? Each time I've done it they were pretty heavy in residue.

 

230K without any oil burning sounds like a great accomplishment! How often are you cleaning your egr, are you running an oil catch can, what is your oil change interval, and what weight oil are you using? Many thanks in advance!

 

I think the B line is where if you let it get to the B line the dealership makes you their B#@&h

moto g power ?

 

Unfortunately, I didn't think about taking pics until I was half way through the job. So the intake ports and manifold pics are after cleaning. They were pretty grimey, and the worst thing was all the liquid pooling up under the throttle body.

I think changing the waterpump at 160k miles like you did, and frequent coolant refreshes, probably saves a lot of head gaskets. Without a temp gauge it's tough to know when we're running hot. And 5k max oil changes too.

I think heat and poor gasket design/quality are the culprits on blown head gaskets. And as far as the notorious rough knocking cold startup - I'm guessing temp and moisture at the intake are the problem. I'm less suspicious of the EGR system causing these problems, especially when no fault code is indicated. But keeping things clean is time well spent.

 

We run 0W20 full syn regular/not high mileage, no oil catch can (not opposed to, just not done). Interval was 5k mi, at about 182k we switched to 3k mi on the advice of Toyota tech Son as he said he feels that older engines it's cheap insurance as some buildup is inevitable. Did the Egr cooler service at 109k, 182k, 218k. 218k was not very dirty at all. I'll probably wait 50k for the next round as the job is a bit time consuming.