EGR Cleaning?

[Wooster]

My 2010 Prius has 80k on the clock.  There are many reports on priuschat.com/ of early Gen3s having high oil consumption, leading to blocked exhaust gas recirculation manifolds and stuck ERG valves which leads to blown head gaskets, and wrecked engines when they run over 100k miles.  My local (and trusted) Toyota main agent confirm that these failures do occur in the UK.  When asked about any preventative measures I could take the Dealer's Service Manager said: " Unfortunately the labour time to clean the valve and manifold is close to 4 hours so it is not included in a service." 

So, I was wondering, would it be possible to use some sort of solvent?  I found many ERG cleaners and here's a few from Halfords      and Amazon

There's an interesting explanation about the whole issue here from an website in the USA

I wondered:  1) Anyone has experience of these:  2) What you think of this simple preventative idea?

All thoughts welcome!   😊

Andrew

 

 

 

 

[TonyHSD]

Hi, there is no preventative thing to do except regular oil changes, quality fuel and service on time. The best way is to take everything apart and clean it properly, 80k miles 10 years old car might be the right time to do it. If you don’t do on time you will notice knocking noise from the engine at specific situations when Battery is drained and you are driving 20mph or less and ice changes load and rpm, it is not only unpleasant but driving like that can cause clutch failure, a repair bill over £1.5k. Best is to clean it and enjoy your hybrid car. Many videos and comments on you tube, Prius chat and here. 
Regards 

[Wooster]

Hi TonyHSD - the car has regular (every 10k miles) servicing using Toyota 0w20 oil.  My local petrol station is Shell, so I always use that.  I know the best idea would be to clean it but I've seen the videos and I know it's beyond my capability.  The options seem to be to pay for someone to do it (£300?) or a £10 cannister of ERG cleaner.  Hence my question about the effectiveness of the ERG cleaners. 

[QuantumFireball]

If these spray cans are intended to be sprayed in the inlet manifold while the engine is running, doesn't that mean it's going to force all that crap through the engine? Maybe diesels are a bit more tolerant of doing things like that (being comparatively dirty engines anyway) but I'd be reluctant to do that on a petrol, especially as these engines have less than perfect piston rings as it is.

Without disassembly and inspection you'll never know how effective any cleaning solution is. And as we know a blocked EGR system on these engines can lead to head gasket failure, I think it would be best to get it done properly - but no need to go to a main dealer, any competent mechanic should do. The EGR cooler gets clogged up on these, it's full of metal fins so I can't see any effective way of cleaning it out without removing and inspecting it (it needs a good soak or pressure washer AFAIK).

You can remove the EGR pipe easily enough, looking at the state of that might give you a better idea of how clogged the rest of the system is.

I suspect the issue is more common in the US as they use lower quality fuels (and lower octane), but I'm not sure.

[fordulike]

Just my experience from using an EGR cleaner on a previous Nissan Almera 2.2 DCi. About once a year I would have trouble with a flatspot on the rev curve at around 2k rpm. I assumed it was a sticky EGR valve or a sticky variable vane turbo actuator. Even a good high rev blast along the motorway wouldn't help, but a can of CRC EGR cleaner through the air intake, plus a good high rev run would solve the problem. At least temporarily for another year.

Not a long term solution, but worth a try IMHO. A proper strip down and deep clean is probably the best way.

[Wooster]

On 6/8/2020 at 9:18 AM, QuantumFireball said:

If these spray cans are intended to be sprayed in the inlet manifold while the engine is running, doesn't that mean it's going to force all that crap through the engine? Maybe diesels are a bit more tolerant of doing things like that (being comparatively dirty engines anyway) but I'd be reluctant to do that on a petrol, especially as these engines have less than perfect piston rings as it is.

Thanks for your thoughts.  I would have hoped the spray cleaners would have reduced the dirt in the EGR to vapour or - at least - microscopically small particles, so it would damage anything else 'downstream'.  But you have a good point. 

[Wooster]

Does anyone know:  Will the 'insufficient air through the EGR' warning light / fault code appear before it becomes catastrophic?  Can i just drive the car, safe in the knowledge that I'll have sufficient warning to get it fixed before any damage is done?

[Stivino]

I have found that there is nothing on the market that will break up the crud that gathers inside an EGR valve, brake and carb cleaner just bounce off it.  The valve has to be removed and scraped clean.

 

[QuantumFireball]

3 hours ago, Wooster said:

Does anyone know:  Will the 'insufficient air through the EGR' warning light / fault code appear before it becomes catastrophic?  Can i just drive the car, safe in the knowledge that I'll have sufficient warning to get it fixed before any damage is done?

From what I've seen on US forums like Prius Chat, it's usually too late before fault codes appear. The general recommendation seems to be to clean it every 100k miles or so.

[TonyHSD]

Correct, even before 100k miles better. 80k perfect time to do it. Do not use any fuel additives or other tyres of cleaning agents in fuel tank or through throttle body, these won’t help and can even add more trouble. When I went to Toyota St Albans to consult with service technician about that problems there were two Prius gen 3 in the garage for same cleaning procedure. If you can’t do it yourself, can’t afford to pay £300 to dealer, there are some independent garages that can do for around £100, I don’t know about quality of workmanship though. I did it myself using 3 cans of special cleaner spray, Jet wash, metal spoke to push through the Finns and took me two days. Done it little bit late at 140k, but last 80k miles where done in year and half time on motorway. Driving in town , short trips it’s usually worse and requires cleaning more often. 

Listen for the knocks, this what rings the bell for urgent egr cooler cleaning. You will need to do intake manifold and throttle body clean at same time for max efficiency. 
Regards 

[Wooster]

Thanks TonyHSD.  The video clip is fascinating and appalling.  What is it that's making the dreadful knocking?  How does a blocked EGR valve end up making that noise?

[Gerg]

The engine is designed to use recycled exhaust gas a fairly inert 'filler' gas that is put back into the engine inlet in a controlled manner, via the EGR circuit, to regulate the combustion chamber temperatures.

The hybrid engine is calibrated/coded to run its combustion temperatures within normal limits of temperature/pressure, with the assumption that the EGR circuit (EGR valve, EGR cooler and dedicated inlet manifold orifices) are free-flowing.

If, however, these elements get blocked-up with combustion deposits from the recycled exhaust gas, and/or vapours from the crankcase ventilation system (aka the engine breather), then this system is no longer of use to regulate the engine temperature in the 'burn' part of its cycle, and the engine will start to 'diesel', hence the knocking sound like an old-fashioned diesel engine.

Instead of the controlled ignition triggered from the spark plug, and its attendant smooth (but fast!) flame progression through the combustion chamber, the petrol vapour is spontaneously combusting, due to excessive heat/pressure in the combustion chamber before the spark occurs, this is known as 'pinking' or 'detonation'.  These phenomena are actually slightly different to each other, but that is detail that you don't need!

The engine isn't designed to operate with these large, incorrectly-phased pressure spikes (which is what you can hear), and damage to the mechanical parts (especially the head gasket on these Toyota engines) can follow if it is not attended to.

Basically, higher combustion chamber temperatures/pressures are good for engine efficiency, but only so long as the engine does not stray into the realms of detonation.  The hybrid engine is running closer to the edge of the normal safety margins than most engines, with the aim of chasing extra mpg.

That's my take on it as a layman, I'm sure Tony would probably have said similar if he was near a keyboard!

In this aerial view of your engine, with the top plastic cover removed (left is driver's side on this), the EGR circuit has the red arrows pointing to it. The lowest arrow is the EGR valve, the middle two arrows are the cooler. The upper arrow is the feed-in from the exhaust pipe.

 

 

[TonyHSD]

That’s right very well explained by Gerg.👍

 I believe the knocks from the video are actually as a result of damper clutch Springs chatter, the knocks from the misfire are more like metallic bell sounds and very often they are left unnoticed by the average driver. If anyone skip the cleaning procedure there will be consequences and those are usually:  Blown head gasket and or Broken damper clutch, any of these are big jobs and expensive. Here is a video that shows the damage done by the blocked egr cooler.

 

[Wooster]

Gerg - a brilliant explanation. Thank you.   I love your phrase "the engine will start to diesel".  Tony HSD - that video is dreadful.  Interesting but dreadful. Seems like getting someone to clean out the EGR system and inlet manifold would be a wise investment.  Insurance, if you like.  Even at £300 or £400. 

This Prius is proving to be expensive.  Had the Cat stolen last December, so I had the added cost of paying the excess and the loss of many years of no claims discount.  Also paid for a Catloc to be fitted. Now an additional £300+.  Savings in fuel bills (compared to a non-hybrid car) have probably been erased by these additional costs. 

[QuantumFireball]

Well compared to a modern diesel I don't think it's so bad. EGR trouble is inevitable because of the amount of soot they make, not to mention problems with DPFs, dual mass flywheels, and so on.

If you bought a Mazda diesel, you'd probably need a new engine by now :)

[Wooster]

QuantumFireball - I'm just comparing my current Prius with my 2004 Gen 2. Sold it with 140k on the clock.  Only ever had routine servicing plus a water pump failure.  Sold it to someone I still keep in touch with.  It's starting to burn a bit of oil and may not pass the next Mot emission test, but it's been a paragon of virtue.  And look at the current mileage:

[FROSTYBALLS]

A 2004 Prius would be Euro4 and a 2010 Prius Euro 5 - so less emissions controls on the 2004 model and, of course, a different engine.

[Wooster]

9 minutes ago, FROSTYBALLS said:

A 2004 Prius would be Euro4 and a 2010 Prius Euro 5 - so less emissions controls on the 2004 model and, of course, a different engine.

Fully appreciate all of that.  But I expected a Toyota with a full main dealer service history to be trouble free.  As my last Prius and two Corolla's were.

[TonyHSD]

It will be trouble free and it will get to the mileage of your gen 2 but you will need to do all maintenance tasks on time. The cat problems is something that almost everyone suffers soon or late but it is not a Toyota fault but the times we live in and obviously the government that seems unable to cope with criminals accordingly. 

[Wooster]

47 minutes ago, TonyHSD said:

...but you will need to do all maintenance tasks on time....

I have absolutely no issue with doing (or paying for) any routine maintenance.  But the there is no EGR maintenance mentioned anywhere and it's clearly a good idea to have it cleaned out.  At a cost. 

[TonyHSD]

Correct, that’s the reason many owners especially in US have blown head gasket and broken clutches. We better learn from others and not wait until  it’s too late. Actually when its time the car will ask for that. My car started to rattle (knocks) a lot at certain circumstances: 

Drained main Battery, driving slowly at around 15-20mph going over speed bumps, constant acceleration and slowing down, ICE under load and immediately no load at all( similar conditions to the white Prius from the video but while car was moving),  and knocking was unbelievable, sounded not like old diesel but worse, like it is going to break apart. If you don’t want to do yours right now, just pay attention to these symptoms and act ASAP . 
Regards 

[Wooster]

Tony - at what mileage did your car 'ask' for the EGR system to be cleaner?

[TonyHSD]

Hi,

at around 135k miles, 9 years old, but I do high motorway miles and this helps accumulate less soothe. I also done egr pipe & throttle body cleaning at 60 and 100k miles.
There is one more important thing that it is not in Toyota maintenance book: Battery fan cleaning, this helps keeping Battery cool and prolong Battery life plus helps efficiency. 
Regards 

[Wooster]

Tony - yes, I know about the Battery fan cleaning.  Mine was virtually clear when I last checked.  But, back to the EGR.  Alll exhausts are 'sooty', just run your finger around the inside of any exhaust pipe!  As the EGR is plumbed directly into the exhaust, wouldn't the designers have expected the EGR to become full of soot?  And - if so - why isn't there some removable filter?

[TonyHSD]

Good question, but I don’t know of any material that can be used in that environment as filter element and be changed on regular basis. As far as I know the next gen Prius 2016 has better design of the egr cooler that may not require any cleaning procedure for longer intervals, but I am just a consumer like anyone else here, I am not connected with Toyota cars in any other way therefore I can’t really answer your questions about Toyota cars design and engineering. Enjoy your car and if you notice any knocks or rattles like the one we mentioned just act quickly and you will have no troubles. 
Regards 👍