Death rattle 2012 prious

leak down test: search how many miles on her? egr cleaned?

 

Well if you're not losing any coolant then you're Not having that issue due to coolant ingress. Condensation is a stretch . More like a flood. But ya better scope the gasket surface internally.

 

I have the same thing going on. No coolant loss. I follow the Car Care Nut. He is is a 20 year Toyota Master Tech, who opened up a Toyota only shop in Chicago. In his head gasket video, he show that when you pressurise the cooling system and look into the cylinder,you only see a couple of drops of coolant. Thats why you can have a missfire in the morning and then the coolant burns up and the car runs fine.

 

Yes I'm well aware I have met same tool and seen same many times only on certain engines mind you .I personally try n steer clear of problematic engines regardless of the vehicle it's sitting in . Unless in the grand scheme of things we already have worked out that were changing it to . And do on.

 

By the number of times that you have misfires (rattle) after doing a cold startup of the car. If it only happens one time, it is condensation. If it misfires several times during a week, then it could be coolant seepage past the head gasket.

How many miles on your Prius?

 

It is very possible and even common to have an occasional severe startup rattle due to an hg leak and not lose a noticeable amount of coolant.

It is also common in the early stages that the car passes a leakdown test and a combustion gas in the coolant test. Combined with no obvious coolant loss, many throw $1000 worth of plugs coils and sometimes injectors at it with no longterm results.

When it gets advanced you then start losing coolant, fail a combustion gas test and sometimes see white smoke from the exhaust when reving while parked.

The dual view borescope looking for steam cleaned pistons and sometimes coolant drips is definitive. Engine cold, coolant pressurized with borescope for possible view of coolant drops.

Car Care Nut HG Borescope at 660s

It can get worse when advanced hg is ignored

 

It may not show itself until heated . Then it cools water has moved a bit waiting for startup and burn off . Then heat and expansion can seemingly close up all the leaking . Until it cycles again cools n heats . Multiple materials involved Aluminum etc expansion rates differ . Lots going on to someone standing they're in their scrubs in hospital Park lot. Just saying.

 

get a code reader and scan for codes. Harbor Freight has the kit to do a chemical test for head gasket leaks. This is pretty easy to do; look for videos on this process. You can pull the spark plugs and compare #1 against the others. You could consider doing preventive maintenance and clean the EGR cooler and passages as well as check out the PCV valve.

 

That kit checks for carbon monoxide in coolant, which is not the usual 3rd gen Prius failure mode.

Head gasket failure.

 

Let's start from the beginning. Your 2012 Prius has 190k miles.

Please describe when you have misfires (death rattle). Does it occur during cold start-up of the car? Does it occur when the engine is warm and you start the car?

When did the misfires start to occur, miles and how long ago. How many times have you had misfires when you started your car?

The more information you can provide, the better the answers will be from the forum members.

 

The 'condensation' issue (which led to an intake manifold revision) has to do with water condensing out of EGR gas, inside the small-bore EGR passages in the manifold, happening if the engine is started for a brief run and not warming up (say, just to move across the driveway or something) and then allowed to sit. On the next start after that, the sudden reduction in intake pressure while cranking 'snorts' the condensed water out of the small passages, and leads to brief horrible misfiring that quickly clears up. It can generally be avoided by not running the car for really short trips where nothing warms up.

If what you're experiencing fits that specific pattern, that could be what it is. If it isn't that specific pattern, it's probably something else.

 

And clears quickly if you ready the car and step on the gas immediately you will almost not even know that rattle was going to exist . If car cranks on own unassisted rattle from hale happens. Step on gas before the magic and you'd never know the condensation was they're worked on our persona

 

This test indicated on my 2013 when my head gasket failed. I had coolant running into the #1 cylinder. the test passed after I fixed it and also a few years later. I guess that is just 1 data point.