Does the EGR cleaning/replacement actually fix the death rattle?

Have a 13 Prius with 165k that’s used as a highway work commuter. It decided to start doing the death rattle knocking on startup recently and I’m wanting to keep it alive and not have it blow the HG or have to replace the car. Always been dealer serviced and to my knowledge doesn’t burn oil. Coolant level looks full, but did have a “burp” when opening the reservoir. Oil didn’t have any emulsion/milkshake going on, so guessing no head gasket issue…yet.

I read about common EGR issues on these cars so I figure mines dirty as it’s never been opened up in 165k. I wasn’t planning to work on the car as I don’t have a garage and it was raining, but pulling the EGR tube seemed quick to see if it was gunked up. The tube did have some deposits but nothing horrible IMO. Cleaned it out with brake cleaner.

Stopped raining so decided to go further and pull the intake manifold - found puddle of oil inside at the bottom and the PCV tube with like a sediment sludge inside. I didn’t replace the PCV but for less than $10 I definitely will at some point. Also see why the oil catch can is something people do on these. The intake ports were a bit dirty but nothing was actually clogged enough to prevent air flow. I sprayed it out with cleaner and probed around with a long screwdriver but didn’t have any bottle brushes to get in there really good.

I figured the EGR valve was a culprit and decided to pull it off without the cooler (saw it could be done that way in a video) since I didn’t have enough clamps for the hoses and again wasn’t planning on taking apart the car that day. EGR Wasn’t as filthy as some pics I’ve seen but I sprayed it out to at least help it a bit. Didn’t take off the black cap to do a full cleaning on the plunger. Didn’t touch the EGR cooler as I didn’t remove it, looking inside it didn’t seem that clogged either, just dirty as I’d expect anything connected to the exhaust to be.

So having done some cleaning on these parts I figured it would help. I’m not sure if it did anything as the problem persists. In the two weeks since doing these, sometimes the car will run fine without issue, but other times it will buck and rattle whether it’s a cold engine or hot (like after stopping at a light). It goes away in higher rpm’s. Recently one of the bucks was enough to trip a check engine light, I figured it’s a knock sensor maybe(?). I don’t have a real code reader, just a Scangauge2 and it says two codes, but only one code shows up as P0000 or something like that (I see as a general code since scangauge can’t read it like a proper scan tool?).

I didn’t do any disconnect on the 12v battery for any of this. Saw reference to doing this with EGR service?

I’m wondering what I should do next? The car is due for service and I’m dreading they’ll just say I need to drop like $2k+ for EGR parts or a head gasket, etc. I’d like to avoid that if possible. I can replace the EGR stuff myself if that’s the fix.

I’ve contemplated just buying a brand new EGR cooler, EGR valve and intake manifold - to swap in and keep the old ones to fully clean out for next time. Those parts seem to be around $900 from a local Toyota dealer who seems to have better prices than others.

Do you think this will actually resolve my issues or should I start thinking about trading it in?

thanks

 

Can you clarify what you’re saying?

 

Whatever the issue is, the shake or knock or whatever has only happened about a dozen times from the 6-7 times it’s been ran since I first heard it, otherwise runs as normal.

Sounds like you’re both saying it’s going to need a HG or a replacement engine though based on what I’ve mentioned?

what are other signs of a HG failure? Coolant level looks same as when I started monitoring and no milkshake oil or smoke from tailpipe

 

Read a little about HGs it definitely sounds like those symptoms are what I’m experiencing. I definitely don’t want to bend or throw a rod so I guess it’s time to park it until I get it resolved. Dang this sucks.

Thanks for the advice.

 

HG was the issue. Toyota wanted $4200 for HG, but in my research I discovered that for half the price you can get a mobile HG service in CA, through Gasket Masters. They could even do a whole engine swap with rebuilt engine (vs unknown condition used engine)

On the gasket it looked just barely breached between cylinders 1&2; guy said it was an early catch. They use a FelPro head gasket instead of Toyota - it has raised ridges to help prevent failures, whereas the Toyota one is flat.

Only driven it 100 miles so far, but seems like it's got more power, runs smoother, and my trip fuel economy went up too.