Parasitic battery drain?

The inference being that lawsuits for dangerous shortcomings are more likely to succeed? For sure, but I've heard the phrase "reasonable expectations". You put down $30~40k, and expect trouble-free use, as long as you keep up the basic maintenance. And if the unforeseen happens, you expect the seller to step up.

My take, Toyota engineers were asked to up the fuel efficiency, and came up with a couple of boners:

1. low-friction piston rings, always beneficial to efficiency, but weren't able to corral the oil
2. EGR system that allowed leaner burn, but clogged, and blown head gaskets ensued

I guess the manufacturers are getting pressured by increasing competition, increasingly stringent environmental concerns, margins are tight, corners get cut, and here we are.

 

Remember we live in the US where "reasonable expectations" fall in a category of consumer protection which is limited to contractual terms like warranty, not what the consumer thinks "Toyota Reliability" means.

Repeated and demonstrated safety flaws like sudden failure of an inverter in the middle of an 85 mph turnpike or a 0 degree blizzard outside of Bozeman can be sometimes litigated with a class action. Usually the big winners are the lawyers while the members of the class receive repairs but no compensatory damages worth talking about.

Toyota is actually a hero most of the time by voluntarily extending brake booster and inverter warranties without legal pressure AND by adding to the inverter warranty after class action WITHOUT pulling the standard US delay, appeal and appeal again corporate strategies.

A less consumer friendly company in the US might sue Mendel for defamation because of a perceived false statement that was published and negligently harmed their reputation.

Often the threat of defamation is used to shut down free speech or a suit against the company. If someone was actually hurt, a small "settlement" might be made tied to a legally binding off the record non disclosure agreement.

 

Just out of curiosity, how often do you change your coolant?

 

It's an odd answer. Each oil change since I got the car at ~135k mi. I open the radiator drain and as it's flowing add ~ 1/2 gallon of that ready to use 'Pink Asian Cars' coolant. Strive for ~5k mi OCI.

 

Ahh. So you've only owned the car for a little over 30k of it's life(or about 20%). I wonder what the previous owner did. It should be on it's fourth coolant change by this point. (original, 50k, 100k, 150k - or original, 2014, 2019, 2024)

If the original owner(s) never changed their coolant, that might be a factor in the head gasket.

 

OK, so you're in the 'Coolant change or head gasket fails' camp.
Do other toyota engines have this failure rate related to coolant changes?
Does the owner's manual call for 50k mile coolant changes?
The coolant has always looked like new from the time I've owned it. I'll have to look at the title to see mileage when I bought it. This is my 3rd Gen3, second HG failure. I can't remember all of these numbers....
I never used test strips on the coolant.

There are other 'camps', the 'EGR clogged makes the head gasket fail.'
Some say it's the fate of the thermal cycles hybrid engines go through, but then there's the Gen2....
Some say it's a pizz poor design and that's why the Gen4 is whole new engine.

I rented a new Corolla to do a 500 mile gig yesterday. Boy was that a blast from the past....
Does it have EGR? Does it fail if you don't change the coolant?

 

Just for the record, Toyota specs 10 years or 100k miles (whichever comes first) for engine coolant.

For second, third and fourth gens if I’m not mistaken. Gen 3’s the problem child.

 

The manual says 10y/100k on the original engine coolant, then 5y/50k after that. I personally(on the advice of an extremely experienced Toyota tech) go with 5y/100k on the original and 5y/50k after that.

Manual says the inverter coolant can go 15y/150k on the original and 5y/50k after that. I just plan to do it on the same schedule as the engine.

It's not the cooling abilities that go bad over time, it's the increasing acidity. And the head gaskets have a coating that is susceptible to being eaten away if the coolant gets acidic enough. TheCarCareNut did a video several months back where he showed a dozen+ head gaskets his shop had replaced in the previous few months and all showed the same failure: a portion of the coating eaten away in a channel between a cooling jacket port and the nearest cylinder. The gaskets were mostly from the last generation V8, but he had gaskets from various V6s and I4s as well. They also all had overlong coolant intervals; often still on their original coolant at well over 100k.

I think the EGR system can contribute to the problem if the EGR valve becomes so caked up with carbon that it stops functioning, but I think that's more a symptom of inadequate oil changes that have clogged up the piston rings. I feel the EGR system can handle the carbon of a properly functioning engine, but it can't handle the extra carbon of an engine that has started burning noticeable amounts of oil. Periodic EGR cleaning is the same as using a catch can: you're treating the symptom, not the root cause. IMO

 

So if you don’t have oil burning the third gen EGR won’t clog, or this is just a feeling?

conflation can be sneaky.

 

For the initial coolant. Not for subsequent replacements. Knowing the propensity of the Super Long Life Coolant for going acidic over time(more than milage), I'm just not comfortable with anything over 5 years, even for the initial coolant. I'm okay with the 100k miles on the initial coolant, just not the extended time.

From page 51 of the 2010 Prius Warranty and Maintenance Guide:
3 Initial engine coolant replacement at 100,000 miles/120 months. Replace every 50,000 miles/60 months thereafter. Initial inverter coolant replacement at 150,000 miles/180 months. Replace every 50,000 miles/60 months thereafter. Refer to “Engine/Inverter Coolant” in the “Explanation of Maintenance Items” section in the back of this guide for more information.

 

Well, I don't have personal experience as I never got my 2010 beyond 100k miles before I traded it for my 2023. I do know that I replaced my EGR valve and pipe at around 80k and they looked absolutely fine(replaced as part of a major maintenance service because I had not followed the service plan I now advocate - and I thought I was going to own the car for 5-10 years more). Even though I did 10k changes for the first 50k(because I didn't know better), I didn't build up enough carbon in the rings to that point to start any blowby. But that was a sample size of only one engine, so I'm not willing to draw hard conclusions from it.

What I would be fascinated with would be a good size survey of Prius owners with EGR problems that started with the following questions:
1. When did the EGR problems begin manifesting?
2. Does your Prius burn oil between oil changes?
3. If so, when did your Prius start burning oil(to the best of your recollection)?
4. If your Prius burns oil, how much per 1000 miles/1600km?
5. How often do you change oil, how long have you owned the car, and do you know the service history prior to your ownership?
6. Have you had the engine borescoped to check for cylinder scoring?

It would be very interesting to see if there are any patterns between oil consumption and EGR issues.

But let's think about this logically. EGR systems get clogged because of carbon buildup. A big proportion of oil is carbon. We all know the rings in hybrids in general and the early gen3s in particular have a tendency to get stuck and start causing blowby(excess oil entering the combustion chamber and getting burned).

Now it's time for Occam's Razor. What's the simpler scenario? Toyota designed an EGR system that can't handle a standard amount of carbon? Or that the known piston ring problem eventually causes excess oil into the combustion chamber which is burned into excess carbon which then overloads the EGR beyond what it was designed for?

I'll also suggest there's a big difference between dirty and clogged. The inside of the EGR cooler will always be dirty. You can have a perfect engine, clean the cooler so nice you could eat out of it, then drive the car for a hundred miles. You open that cooler up again and it's going to be dirty. The question is whether the EGR cooler is so caked in carbon it can no longer do its job, if the EGR pipe is so clogged it has significantly reduced flow, if the EGR valve is so caked it no longer open/closes properly, or if the EGR channels in the intake manifold are clogged up.


Anyway, that's enough of a rant for this morning. I doubt I'm going to change your mind, and I doubt you're going to change mine unless you can show me a lot of data points of real EGR problems in cars with a history of zero oil consumption. I'm willing to be convinced, but I'd have to see some real numbers. Until then, we can respectfully agree to disagree.

 

You replace that simple 90° stainless steel EGR pipe?

I thought it was the uneven EGR flow to the cylinders that caused uneven EGT and/or combustion pressures that cause the head gasket to fail at the usual 1 and 2 area.
The cooler or the valve would evenly lower the flow. But if it gets too low, you get a code, correct?

What about testing the coolant while it's still in the car? Are there any good test systems?

I'll try to get good pics of my intake manifold's EGR passages. We'll see if the clogging is where the HG failed.
My 167k mi engine is only using ~1/4 qt / 6k miles.
I would think carbon crud is carbon crud. It comes from burning gas mostly, with a little of the oil consumed.

On that note: We need to Stop Burning Stuff.

 

Surprise !!!

We're off topic.....

 

I do know this stuff.

“Cooler” is a colloquial term we’ve coined, Toyota calls it “pipe”. But it is an apt term; its function is to cool the exhaust gas, hopefully without getting in the way too much.

How much cooling do you think it does, with even 0.5 mm of fluffy carbon on its radiator fins? How about when it’s progressed to a near-solid lump of carbon? In gen 3 forums this has been hashed over ad infinitum. Not much consensus, lots of conflation.

 

It is just as likely to be adding heat to the antifreeze.

The part for my v is called a cooler and is available from Japan in a week for $102 new on ebay,

 

That is the objective.

In the past I'm sure I saw just "pipe". Perhaps it was truncated description. Any way, term "with cooler" is used by Toyota USA:

Exhaust Gas Regulation Pipe Sub-Assembly with Cooler #25601-37010 | Autoparts.toyota.com

 

I'll take a crack at this 'survey' !!

1. IF the uneven clogging of the intake EGR ports results in a Failed Head Gasket,
the first 'manifesting' was a short 'stumble/misfire' I experienced only twice after a warm start up and while adding power to accel into traffic on a long trip.
The next morning I found the coolant was down ~3/4" in the reservoir. I topped it up and drove another long trip which also used coolant but no 'misfiring' was felt.
2. Yes. (don't all engines have to consume a bit of oil?)
3. Always during my ownership, very minor usage, imho.
4. ~1/8 qt. between ~5-6k mile oil changes.
5.~5-6k miles. Always Mobil1. Don't know previous ownership records, but it must have been decent because of current consumption.
6. Of course not. Why would I do that with such a great running engine, until just recently?
I suppose I could pressurize the coolant system and try to see the 'spot' where the head gasket has failed... but who cares at this point.
It needs to be repaired. And it will get a better than stock head gasket,,, I hope...
7. A big portion of gasoline is carbon also. How many tons of gas vs oil gets turned into waste carbon?
8.Ya'think? It may be the distribution method used in the Gen3. Hot EGR gasses are passed from one side of the cold plastic intake manifold across to the other side. The far side clogs up first because the gasses cool and condense in the tiny ports.

(More about this in the next post.....)

It would be interesting to see if there's any pattern between doing all of this 'Off-Book EGR system cleaning and Head Gasket Failures.
If it's vital to do this EGR cleaning... why is it not in the maintenance manual?

 

Toyota would have to admit their EGR implementation was woefully inadequate, be responsible.

 

Previously stated:
"It may be the distribution method used in the Gen3. Hot EGR gasses are passed from one side of the cold plastic intake manifold across to the other side. The far side clogs up first because the gasses cool and condense in the tiny ports."

I rented a '24 Corolla to do my driving gig for a day, because my Gen3 has a failing head gasket.
This is a picture of the EGR system.
The EGR heat exchanger is just below the EGR valve, which you can see is also coolant cooled/heated.
The plastic pipe routing the gasses to the intake may be insulated to keep the gasses warm.
The pipe enters the intake manifold in the center of the intake and you can see the distribution tracks on both sides of the intake manifold.
It would be fun to see the EGR ports in this style of intake manifold at ~100k miles.

[/QUOTE]

 

True.
But then what about the rest of their fleet that uses EGR?