Can EGR go bad?

Likely head gasket has failed, is leaking coolant into cylinders, and the “death rattle” is due to engine’s struggles to compress the coolant.

that was the first EGR cleaning?

 

I agree that the likely problem is that the head gasket is starting to fail.

In the early stage of the leaking head gasket in the Gen 3 engine, the "death rattle" is due to misfires caused by the leakage of coolant into the cylinders. The coolant cause the spark plug to create a weak or no spark from the plug until the coolant is forced out through the exhaust valve of the cylinder. Then, the spark plug will work properly, and the misfire will stop occurring, and the engine will run smoothly again.

In the advanced stage of a leaking head gasket, you could get enough coolant into the cylinder for the engine to struggle to compress the coolant in the cylinder. Once that occurs, you will bend or break the cylinder rod. If that occurs, it is time for an engine replacement.

 

There's probably a continuum involved, where enough coolant can collect to effectively raise the compression ratio and make the compression stroke harder to complete, but before it gets so hard as to break something.

But it's worth remembering that none of that is necessary to make the awful rattle. It is a big noise, but does not need a big explanation, and even simple misfires in a Prius cause that noise. This classic story concerns a Prius that was let go for scrap price when the awful rattle came from misfiring caused by a single spark plug, and there was a quite recent thread here where someone seriously considered letting the car go for scrap price and the cause of misfiring was an injector.

The engine is connected by fixed gearing to two massive motors (and one of the massive motors is further connected by fixed gearing to the whole mass of the car). Misfiring makes the rotational speed of the engine uneven, and the car isn't able to control the motor rotation precisely enough to match those variations, and there is always some lash in the gearing that can clunk back and forth. There's a torque damper between engine and transmission to make the clunks a little less bad, but that takes its toll on the damper too.

That's not to say your trouble is a spark plug or injector. If there was white smoke, head gasket sounds like a good call. The point is just that the misfiring caused by coolant's presence in the cylinder is already quite enough to explain the awful noise.

 

It must be the plugs since they were never changed.

 

That would not explain the white smoke at the exhaust though.

 

Where does it say that spark plugs were never changed??????

 

I’m pretty sure @Grit is being sarcastic.

regarding the title question, about EGR valve going bad: could carbon clogging of the system necessitate more travel in the valve, accelerate wear on the “ski jump ramp” ?

 

Seemed like Grit was being snarky and ignoring the last paragraph of #4.

 

check coolant if it’s low, sounds like a head gasket. White smoke indicates coolant is being burned in the combustion chamber.

 

No posts from the original poster mentioned that spark were changed so it would mean plugs didn’t get changed and caused head gasket blow.

I can break the logic down to very simple common rule of deduction if needed.

 

You do not have to replace the engine.
@NutzAboutBolts (posted above) has a video detailing the head gasket replacement - along with a wealth of other G3 info on the YouTubes.
Like.
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If you do not have the ability to replace the gasket, then give Home - Tampa Hybrids Inc. a call.
You're right next door if I remember my Florida...
They probably have people or know people in this forum.
At the very least you should do a leak-down test or have one done - and try not to drive the car until you replace the gasket or you might hydro-lock the engine - and THEN the "replace engine" light will be illuminated.


Replacing the gasket is less expensive than replacing the engine......or the car!

Good Luck!

 

WHAT ?????

Using your same "logic" - The OP did not say that he changed the engine oil, "so it would mean" the oil "didn't get changed and caused head gasket blow".

OR

Using your same "logic" - The OP did not say that he changed the engine coolant, "so it would mean" the coolant "didn't get changed and caused head gasket blow".

OR

Using your same "logic" - The OP did not say that he rotated the tires on the car, "so it would mean" the tire rotation didn't get done "and caused head gasket blow".

Etc, etc.

Please break down the logic to "very common rule of dedication if needed" for me. I do not understand the logic that you used to determine that not changing the plugs caused the head gasket to blow. I have never seen or heard of old spark plugs causing a head gasket to blow.

 

^ DANGIT!!!!!

Every time I think that I might achieve my lifelong dream of being quoted in @Grit 's signature I am confronted by the fact that I am hopeless outmatched in this forum....


BTW:

Can EGR go bad?
No.
The EGR cannot 'go bad' because it was already bad when the car was built!

 

^ this!