2012 Prius - The Good Ol' P0301 Gremlin!!!

That's possible, but I don't remember seeing any coolant spilling out when I removed the EGR. Also, before I attempted the repair I had coolant leaking out on the pavement.

 

No head or engine block warpage. The car never overheated. Any how, so no bent rod(s)

I was able to find a long enough 1/4" extension to measure piston height. Wrapped the extension in painter's tape, stuck it down cylinder 2 and marked it with a sharpie. Made sure to lean the extension into the spark plug threads. Then stuck it down cylinder 3, making sure to lean it into the spark plug threads too. And cylinder 3 hit the same mark. What a relief. Visually, they looked off.

The source of the external coolant spill has to be a hose somewhere around the driver-side cylinder/EGR area. When I was still driving the Prius, when I took off the coolant tank cap, a rush of air would blow out. Exhaust gas pressure leaking into the coolant system must have caused a rupture or ejection from a hose connection somewhere. I'll leave the splash panel off for a while after I get her going so I can determine where the leak is.

Been moving really slow on this. But today, got the timing chain cover, chain tensioner, valve cover, water pump, and oil filter housing on. Torquing in the timing chain cover was a total pain since there is so little room. Tomorrow starts with the engine mount and then I hope to finally be done with this.

 

Welp, I finally got her all back together. She didn't rattle as violently as some of the videos posted on Youtube upon initial restart. But it did take a good while for her to start purring again. Man, I sure did take my sweet time with this repair. But it was fairly simple. Toyota engineering FTW!

But, I do have a P0328 code. Cleared the code and it immediately came right back. Time to take the intake off and do some snooping with the sensor. I know a few of the latches on the connectors completely obliterated when I removed the harness. We'll see how this goes. Saga isn't over yet.

 

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Turns out I didn't reconnect the knock sensor behind the intake. There are two connections for that sensor. One part attached to the dip stick which attaches to the harness. Then that component connects to the sensor which is embedded into the ICE. Reassembled the intake after making the connection and fired her up, Code was still there. Cleared the code and this time, the CEL didn't come back. Went off and got dinner. After dinner, I inspected under the car to see if I got any coolant spillage anywhere. None to be found. I inspected the hoses as I was re-assembling the EGR system too, I could find no cracks in any hoses. But will keep an eye on it over the next few days as the spill was quite significant previously. Might need a longer drive to really increase engine temps. But while I was at it, I popped the hood just to see what would happen if I unscrewed the coolant tank cap. No rush of air from decompression to speak of. Just a ploooomp, which is the sound of coolant surface tension breaking as the cap came off. No combustion gas in the coolant system!

So I did document the steps. Will post that shortly.

 

Very possible considering the coolant spill came from the EGR side of the engine and I did replace my EGR valve prior to the HG job. If a hose was loose, definitely saved me additional expense and might have prevented catastrophic engine damage. The build up of exhaust gas was enough send 1.5 gallons worth of topped off coolant onto the pavement. All told, I put on maybe 2,000 miles since I've had the CEL come on in the last year. Where would have the next breach have been had the coolant not spilled onto the pavement? Probably right into a cylinder. All 1.5 gallons that I topped up with.

 

So not connecting that knock sensor has proven costly. Smog check came back as failed due to code P0328 even though I wiped the code. Have to put 200 miles and 15 cold starts with 10 miles driven at a time with those cold starts till the ECM is comfy with my repairs .

 

Probably true in normal circumstances, but smog shop diagnostic machines might have more stringent testing parameters. I had put on maybe 15 miles on the car between the time I reconnected the knock sensor, cleared the code, and took her in for smog. P0328 still showed up on their diagnostic systems.

In any case, she passed smog on the retest. The shop put a code reader on her and it showed over 300 miles driven and 31 cold starts since the failed initial test. They did that to ensure those prerequisites were met (200 miles and 20 cold starts) before they retested, which is cool of them. Because, they give one free retest. So if it failed again, I'd have to pay full price for a smog test there or at some other shop.

I am getting 42.1mpg combined city and highway miles since the repair. I have a lead foot and am not a hyper-miler by any means. So that is par for the course for me. I see no coolant leak anywhere and I am not losing coolant. So that means I don't have to replace any hoses. I am going to do these things, then call it a wrap:

• Drain and fill inverter coolant
• Change tranny oil
• Re-install splash panel

None of those fluids have ever been changed since I have owned the car now at 149k miles. Also, I was struggling with figuring out how to keep the car level and safely lifted to change out the tranny fluid. But then realized that my driveway is a fairly steep incline. I'll back her into the driveway, then run her up some ramps to level her out. That will get her level and allow for the crawl space needed to get under her. Will chalk up the back wheels of course. Boom, problem solved.

At 170k miles, I am going to do some maintenance on the EGR system again. When I took the EGR out initially, I used a ton of brake cleaner on the cooler. Still saw a ton of carbon in there. I replaced the EGR valve with a new one, so no cleaning was needed there. But I took the old EGR valve and soaked her overnight in Purple Power and that stuff cleaned off all the carbon (I'll post pics tomorrow). No pressure spraying needed. I'll just get a rubber stopper to plug one end of the EGR cooler and then fill up the cooler with Purple Power and let her soak overnight. Even with 4 cans of brake cleaner (@$4/can), wasn't enough to do a good job cleaning the EGR cooler. Purple Power is less than $5/gallon at Walmart and does a better job. The trade off is that she'll be out of commission for 1 day as Purple Power does its thing overnight.

Anyways, I ran into a few stumbling blocks on this repair, so I'll do a write up listing out the steps to save other some time.

 

Am I missing something? I CTRL+F your link and didn't find anything on confirmation driving pattern or P0328? Just reference to commercial resources to address DTC's. You obviously know what the driving pattern is. Why not just paste it here and share? Isn't that why we are here?

In any case, like I said, she passed smog. Also, the shop gave me parameters to follow on the smog retest: 200 miles + 15 cold starts. They also ran a scan to confirm I met those parameters for the retest. So even if what you say is true, the shop might not have retested my car if I had not met those parameters.

Poured it in a spray bottle with plans to use it to clean the wheels on my truck later. I used 2 SOLO cups for the overnight soak.

Keeping my eye out on one. If it can be had for cheap, I'll grab it. But all the used ones I see are going for a pretty hefty price (relatively speaking).

Here is what the EGR valve looked like before (from an earlier post). No scrubbing or agitation of any sort. Just a soak and a rinse to wash away residual Purple Power:



And after the overnight soak in Purple Power (no I didn't soak the solenoid):

 

I am guessing it would have taken less time than the hour you spent writing this response