First Timer with an issue

Are you sure you even have a catalytic converter underneath?

 

Could it be a heat shield On the exhaust vibrating?

 

not sure how far from Olympia you are, but maybe I can help?

When the battery level is down to 1 pink bar it has very little power so your engine will normally run much harder and a bit louder to compensate for the lack of electric power. So if the noise is not the sound of a sick engine, just an engine that's running hard, you ought to be allright.

But your battery may need some attention. Do you have any warning lights on your dash? Does the battery always stay on one pink bar?

One thing you can try to get your battery to charge up to more bars is put on your emergency brake, put your left foot on the main brake, put the car in drive and floor the accelerator with your right foot. This will force charge your battery. Let us know if it responds to that?

 

At 11 years old and with that many miles, you likely have BOTH a cat problem AND the HV battery on the way out.

BUT.......first have the 12 V battery tested, maybe twice if the first test comes up good.
Putting ~$150 into a 12 V battery often is a reasonable gamble before you sink over $1K into other things.

The cat and HV battery are both "expected" repairs at some point in time.
One of the pitfalls of buying a high mileage used hybrid.
There may be other problems with the engine looming too.

 

Yes. All of the oil that exits the engine with the exhaust does not burn up.
It fouls the cat and causes smoke and soot.
It may be close to choking the engine off completely.

UNLESS you want to tinker with this car and spend a LOT of money on it over the next couple of years,
I strongly recommend that you unload it......now.

 

And any warning lights on the dash?

Based on everything you described this car shouldn't even be drive-able? Or at least that will be the case very quickly... So many things wrong with it I don't know where to even start.

 

An oil burner with 200k+ miles and needing a traction battery (not to mention exhaust repairs and who knows what else) would be one that I'd send out to pasture with a hearty, "Well done, good and faithful servant."

 

Are you the original owner?

Check the reported mileage and dealer maintenance by running the VIN at : Welcome to Toyota Owners

 

Here's an update on this Prius... It comes with a diagnostic challenge for the smartest most experienced folks on here.

The OP had an exhaust leak fixed by a muffler shop that replaced the flange gasket where exhaust header bolts to the tail pipe and made it 300+ miles to my place in Western Washington. But on the way it lost a quart of oil and the exhaust leak repair failed again.

Turns out the muffler shop didn't realize the end of the exhaust header pipe was damaged on one side and just jammed a larger than normal flange gasket on it and the sharp edge of the damaged pipe end shredded the gasket, which led to it's quick failure. Here's a pic of correct size next to failed larger size that was damaged when installed.



So with a tiny grinding stone I reached way up in there and spent lots of time hand grinding the damaged edge of the pipe smooth again. Then put the gasket in and no more leak from that spot. But...

The engine ran much rougher than a normal cold Prius engine does and then it settled down, but engine compartment was louder than normal and then there was smoke but no engine error codes, no battery error codes.

On closer inspection seems like there's a fine spray of oil leaking on top of the engine that was also getting on the exhaust manifold and it sounded similar to an exhaust leak. But no signs of oil leaking on the ground below, no signs of oil leaking from side of engine where belt and timing chain are, just on top of the engine where oil fill cap and spark plug covers are, which explains the lost quart of oil on its 300+ mile drive to get here, but not sure the source of the leak yet. Just got to this point with it.

When I put in new plugs in cylinder #3 & #4 they were normal looking but #1 and #2 (where the louder than normal engine noise is coming from) did have wet plugs like an oil leak but it was relatively clean oil, not thick dark burned oil like bad piston rings.

So what do you think? Is this a bad PCV valve? A valve cover gasket or valve oil seal gone bad? Head gasket? Back pressure from a clogged exhaust pipe? Something else? Thoughts?

 

Our local FB message group of three think its a bad valve cover gasket...

 

Hmm. You said there was a spray coming out. Seems to me that it would have to be under some amount of pressure to spray. Wouldn't a valve cover gasket just ooze or dribble?

Any chance you can chase it down by holding paper or cardboard in the suspected areas to see if spray hits it and narrow the search that way?

 

Good idea... I'll try that later today... Thanks...

 

Update as of 2pm West Coast US time:

Last night I tried @jerrymildred 's idea of covering the top of the engine in paper to trace down the oil leak/spray. The only part of the top of the engine that wasn't covered is down where valve cover gasket is. Results showed no sign of oil anywhere on the paper, so I suspect the oil "spray" that quickly covered the top of the engine the day before was the oil from a leaky valve cover gasket sizzling on the exhaust manifold and splattering on top of the engine in same way your stove top gets oily when you cook with oil.

Of greater concern is that even though the engine started perfectly for the first time and ran quiet and normal, soon as the engine started to heat up it got noisy and the gasket I replace between end of exhaust manifold and cat started to fail. This is the third gasket on this vehicle.

So just now I started the engine up again and still no error codes and the wind coming out of the exhaust pipe, as well as wind coming out of the oil fill cap area is equivalent to the wind in my own healthy Prius. So there's no evidence of a clogged exhaust system or blowback from bad compression / failed piston rings.

Keep in mind this car that had P0420 for a long time and didn't have it after the 300 mile drive to my place, but it did blow out the newly installed exhaust flange gasket between header and cat. Last night it sounded like the same thing was going to happen again had I not shut the engine down. Glad to realize this morning that all that work to install that flange gasket wasn't lost and it's still functioning when the engine is cold.

Truly baffling this one is!

 

Any chance that you have a leaking crankshaft oil seal and oil is being thrown around?

No way to properly evualuate a P0420 until the exhaust stays sealed.

Posted via the PriusChat mobile app.

 

Had not considered that one, primarily because car has not lost a single drop of oil on the ground below vehicle in spot it's been for weeks. Only oil leaking is right above the exhaust header and in covering top of engine with paper no signs of oil leaking above that point.

As for P0420, the code hasn't come back since the muffler shop fixed the flange gasket and a good amount of the 300 miles to my house was before the flange gasket failed.

In talking with other mechanics they seem to think I've covered everything in terms of diagnosis and to proceed with valve cover gasket and PCV valve replacement and tighten the spring bolts that connects header to exhaust a bit after heating it up more and that's all that need to be done unless we finally get warning lights, of which there's been none.

 

exhaust flange gaskets don't just fail.....
The prius exhaust spring bolts have a positive stop flange at the top of the threads. The bolts are tightened until the flange makes contact with the exhaust manifold surface. Anything less than full contact is an incorrect installation. The photo below is an OEM fastener for the front exhaust flange.

Are you able to remove the cat assembly and blow compressed air through the pipe from each end and through the O2 sensor hole? This should result in significant dry soot blowing out from every opening, so I wouldn't do it inside the garage. If you're not getting good flow out the other end of the pipe then you have a clog problem.

 

Thanks @TMR-JWAP Good points as always!

The flow from my own Prius exhaust pipe at idle matches the flow of the suspect pipe. The original flange gasket failed for some reason, but not sure why? The second flange gasket may of failed due to not cleaning end of pipe that was likely damaged when it failed. Definitely no signs of any of this being caused by road debris.

The third flange seems to seat fairly well but it felt like the thread on the spring bolts ended before there was a sense of it being extremely tight. So if next time engine heats the system up and then there's now way to tighten it further and it doesn't sound healthy, perhaps the collar the two bolts go through are bent slightly forward and need to pull it out and inspect and bend them back towards the back of the car more?

As I'm sure you're aware it's not a very easy part of the car to work on when all you got is jack stands and a floor jack and a bunch of wood blocks.

 

This car finally rolled away this morning after a great deal of delays and exasperation for both me and its owner. Despite every effort to get cat the old cat working again it was just too clogged and I replaced it with a $130 replacement cat off Ebay.

Classic situation of a beat up car that had lots of things wrong with it and not very much money in the budget. Full tune up was done, hybrid battery reconditioned with Prolong system, huge amounts of stuff fixed and replaced, lots of cleaning and repair of damaged body parts.

Main lesson from it all is if you ignore a P0420 (catalytic converter) error code because it's too expensive, you're gonna blow your exhaust flange gasket in front of the Cat and all that exhaust blowing out is gonna do bad stuff, in this case the heat blew out the valve cover gasket, which had to be replaced.