Engine Knock even after cleaning EGR pipe cooler

I agree Toyota has let us down on gen3s and most of the customer support programs are expiring for the early years. Used car prices are high right now and gas prices are rising, both good signs for clean Prius sellers.

Interesting gen2 vs gen3 resale perspective:
Which Toyota Prius Generation Has The Best Resale Value? | Torque News

 

Most likely its pinging especially when the hv battery is low. The knock sensor will adjust the timing within a few seconds. Generally pinging is caused by too much carbon buildup in the cylinders and lower octane regular gas. Fill up with premium when the tank is close to empty and see if the pinging goes away.

 

And they were pretty toothless when in effect. What bothers me is the blatant mercenary (don’t hold back Mendel...) motive: their bottom line, and frayed reputation.

Short version, I’ve lost respect and trust for the company.

 

Try leak down test, and horoscope inspection of the combustion chambers (looking for coolant). Head gaskets are usually failing at cylinder 1 first.

 

My battery may be low I do not do much mileage. I will give the premium gas a try thanks.

Does anyone know if Toyota changed the EGR valve at all after 2012? The sticky valve warranty does not cover later years.

Just curious if you removed the black cap on the EGR valve, spun off the rotor and pulled on the stem to be sure it does not stick?
Can't clean it this way but easy to test if it sticks. Can also grease from above resulting in a grease and carbon stem coating that's better than just carbon.

 

The EGR system was totally redesigned for the gen4s starting in 2016 with the hatchbacks.

The shake rattle and roll many discuss here is caused by misfires on start up which rapidly clears, unlike a typical sparkplug, coil or injector misfire.

Traditional engine ping or knock is caused by preignition which is often carbon and octane-based.

"Shakes or Rattles" on a gen3 is most often cold start coolant leaking by a head gasket, which momentarily causes a cylinder misfire and slippage of the engine to transaxle damper. This creates a more violent result in a Prius with a serious metal on metal sound.

 

I recall yes. Query a site like mcgeorge Toyota parts you might be able to see a part no change. Just the valve portion; it’s not a big difference, but side-by-side pics something is noticeably changed. I’d guess something is tweaked internally.

 

I guess they fixed the sticking problem. Thanks for the info.

 

Here is a picture for the 2012 Prius V type EGR valve

 

No kidding, fantastic picture. Thanks!

 

There appear to be two very different crazy shakes you can get.
I experienced the head gasket hydro lock shake once in 2012 the second time I started my new Prius. I think somehow condensation from the new vehicle storage got into a cylinder. I shut the car off immediately. When I restarted it was gone and it never reappeared.
I experienced the missing timing heavy shake with loud tinny rattle in the transaxle area most recently. The EGR valve greasing fixed this.
I still have a weak acceleration rumble. At 59,000 miles will a scanner help me figure out what it is. It is a weird sound like loose parts rattling when I give gas or when the ICU turns on. Oil fills by the experts do seem on the high side sometimes, right on the high mark. I would assume best filling practice on a young vehicle would be exactly in the middle between high and low marks right? Maybe an old car that looses oil would be at the high mark. But somehow I doubt this damaged my head gasket. Will a scanner help me pinpoint the rattle? Is transaxle damper damage something that would show up only in low speed acceleration and go away at highway speed?

 

@Willy Toast, here's a pdf version of your sketch:

 

I don’t think Toyota recommends any grease. If I was going to I might try Permatex Anti-seize, apply and then wipe till it’s almost gone, just a very thin residue.

 

Was thinking about those pesky M5x16 screws on the EGR valve cap. Amazon to the rescue, 50 pack of socket head cap screw style, about $12 CDN.

 

I agree with Mendel. You are mostly trying to remove carbon deposit if you find the valve sticking. I was putting white lithium grease through the small spring moving the stem and scaping the stem where the angle pipe bolts on. At the end it may be best to wipe it all off including any carbon picked up in the grease.

 

I'd think an extremely high-temperature grease, lest it turn directly to carbon itself and gum up the works.

Maybe just dry graphite? It's already carbon. And slippery.

 

It didn't come with any type of lubricant, so why would it need any?
It's not like it's opening and closing a few thousand times a minute like the engine
valve, that don't have any lubricant.
If itis sticking, then take it apart, run the stem on a wired wheel grinder and run a bore
brush through the valve guide.
That should be enough to clean it out and give it a chance to work again.
And if not, you were going to have to replace it anyway so you've lost nothing except some time.