Multiple blown head gaskets in 16k miles

I wasn't going to post a thread on this because I've been posting in the oil catch can thread, but I thought maybe some would find this to be an interesting data point...especially if I keep this car and continue with updates on its condition. Here's the saga so far:

I bought a 2011 Prius in July from a friend of mine that only had for a year or so. He bought it cheap with a head blown head gasket with 232K and the PO had replaced the Hybrid battery at about 200k in 2018 from the dealer.
At 241k head gasket gave up again. He checked the head and it was warped(he suspected it was after the initial HG job but he hadn't checked), had it milled, reinstalled 2nd new HG. He kept it for 500-1000miles to make sure it was good and listed it for sale. He picked up a matching pair of diesel Passats for he and his wife...he never really liked the prius anyway and has always kinda been a diesel guy. I knew HG were an issue with Gen3 but that's all I knew...so to hear that it had already been done and a new Hybrid battery?? I decided it was worth a $4k risk even at that mileage if I could get 3 or 4 years out of it.

It seemed fine for the first 5k miles. Maybe a half a quart of oil used in 5k. Waaaaaay less than my Gen2 uses with 233k. Then I started noticing some rough starting...not terrible but noticeable. I saw the oil catch can thread and installed an oil catch can but hadn't taken the intake off, just wiped it out as best I could from as high up as I could get.
About 1k miles into the next oil change the start up condition worsened to what I considered catastrophic levels coupled with cappuccino looking sludge coming out of the PCV into the OCC and another 3/4"of sludge in the bottom of the intake even after cleaning it out before. 2 very violent shaking restarts happened back to back on Dec. 20th and then I parked it.

I decided the intake needed to come off to do a better cleaning and by this time I had heard about the EGR cooler issue. I asked my buddy if he'd done anything with the EGR cooler...nope.
So I take the intake and cooler off. Intake wasn't all that bad up inside...just the sludge in the bottom and in the PCV inlet. The EGR cooler was plugged solid. After an entire can of oven cleaner and 1/16" brass brazing rod chucked in a drill I was finally getting somewhere with the cooler, but then I was worried I'd do all the work of reassembly only to have to open it all back up to replace the HG.

I decided I would hand crank the motor and see if I could notice liquid in the cylinder by "hitting a wall" at the top of a compression stroke. No luck. I just didn't want to tear it apart for no reason...still torn I pulled the plugs and saw #3 plug was visibly wet. Smelled like coolant, tasted like coolant...looks like I had my answer.

I tore it all apart. I had the timing cover off and on 3 different times. 1st time I thought I forgot to torque the timing chain guide bolts...took the cover off...turns out I had tightened them after all. Damn.
Took a while to clean off the ultra grey. The next night I reinstalled...immediately after which I realized I had forgotten to encircle the water pump/thermostat opening in the cover. Took it back off and cleaned it up again. 3rd time was a charm.
My friend hadn't replaced the valve stem seals either time he had it apart because it wasn't using oil, so I replaced those since they were already in the kit and at 248k why on earth wouldn't you???

Thursday the 7th I got it buttoned back up and fired it up letting it get to operating temp with the heat on high and full blast until the motor shut off on its own. It has been fine so far, in fact the cold start ups have gotten even smoother over the last few days. My initial plan was to sell this as soon as I was done with it and find another Gen2 since we've had zero issues with our gen2...but now I'm thinking maybe I want to see if the OCC and EGR cleaning will make the difference and either prove everyone here right...or wrong...at my expense.
It seems like this car and its history would be a very good data point in the discussion of HG, OCCs, and EGR coolers.
So in summary:
2011 Prius
200k new hybrid battery
232k blown head gasket
241k blown head gasket/head milled
248k blown head gasket, OCC installed, EGR cooler cleaned

I hope I end up having nothing to add to this list...except maybe 80k trouble free miles.

 

Thanks, 50k interval sounds like a pain, but I'll do it at this point!!

I sure hope you're right!!!! I am also pretty surprised that with 3 blown gaskets at this point that I didn't have a bent rod.

Thanks, I'm hoping and praying it's not 3 strikes!!!!

 

Which you could likely change on the side of the road with a few tools hahahaha

SM-G981V ?

 

1,100 miles post HG, OCC, and EGR cleaning and I've had a couple starts that I felt were a little "rough" like a stumble on the first rotation but not death rattle knock rough. Every cold start I get nervous as to what's going to happen.
It's only been 2 weeks so far, and I haven't listed it for sale yet...but man I'm nervous.

Coolant level has maybe dropped a little over these 2 weeks and I can only hope that I've just worked a couple air bubbles out of the system after having filled it without a bleeder valve...also it's colder now...so some contraction too.
The oil is completely clean and looks perfect.

SM-G981V ?

 

2000mile update:

I topped off the coolant after having had the level drop a bit in the first 1000miles. I had hoped it was from an air bubble making its way out and not another leaky GS already.

The coolant level is now stable.

Oil is still at the full mark. Nary a drop seems to have been used.

I feel better than I did 1000miles ago.



SM-G981V ?

 

3,200mile update

3k came and went on a road trip so I checked when I got back.

Coolant level is still holding steady.

Oil is down maybe an 1/8 to 3/16" on the dip stick. I don't believe this will even be a half quart by the oil change...which is about what it was before if I remember correctly. I mean, I've actually only owned it long enough to have had 1 oil change before the head gasket blew so.......

I'm hesitantly confident that this will continue.

SM-G981V ?

 

I got to my first oil change post HG and EGR cleaning this weekend and of course I forgot to check the oil before draining it. Judging by the oil usage up to this point I can't imagine it was down more than a half a quart. At 253k miles

The oil looked pretty clean, much cleaner than my Gen2 oil is with 237k on the clock(and using over a quart and a half of beteween oil changes).

Coolant level remains unchanged, oil consumption is good, and I still debate about getting rid of it before I have anything else catastrophic happen.

 

I have some interesting developments from the last couple of months.

There have been 2 incidents of a knocking start in the last couple thousand miles. After the first one happened I was not a happy camper. After thinking about it though, I remembered having moved the car the previous night in the driveway only to power it off almost immediately after the ICE kicked on.

I thought well I better keep an eye on the coolant level, but I hoped it was just the moving incident.

Coolant level remained steady.

Now the 2nd knocking start...grrr
Then I remembered again, I had done a quick move in the driveway and powered down right after the ICE came on.

I have made sure to allow the ICE to cycle off on its own before powering down for any quick move in the driveway since then.

Coolant again remains steady.

258,670miles for the 2nd oil change since the 3rd and hopefully final HG change.
Less than 1/3 quart oil used.
Oil looked clean and def no water in it.

I'm just hoping that these 2 knocking incidents can be explained by the rapid shut down of the ICE. It seems that is the most logical explanation with only have those 2 episodes and zero coolant loss. I sure hope anyway.

SM-G981V ?

 

I just passed 260k this past week. I am now 12k since the 3rd(and hopefully final) HG change. This is 3k longer than either of the first 2 HG by the PO.

Those 2 knocking starts have been the only isolated events suggesting a problem. I have continued to make sure it cycles off on its own any time I've had to start it just to move it quickly.
I am hopeful again.

SM-G981V ?