This was a perfect example of why so many of us love your channel. You are a man of integrity and great diagnostic skill. Not to forget that you are an excellent communicator. Thank you, as always, brother.

Great work Ahmed, our 3rd generation is running strong that you repaired (head gasket, egr pump, egr valve, intake manifold, water pump, etc...). You are by far the best mechanic I’ve ever had the privilege of dealing with. May GOD richly bless you for your integrity and hard work. Sean L.

@chuckwalla2967

5 ай бұрын

That's a lot of repairs for a supposedly reliable car that's supposed to run forever with just oil changes.

@realfreedom5029

5 ай бұрын

@@chuckwalla2967 it has 195,000 miles

@richardvargus7443

5 ай бұрын

​@chuckwalla2967 it's maintenence. You should be doing coolant and transmission fluid changes on every car you've ever owned.....

@realfreedom5029

5 ай бұрын

@@richardvargus7443 sir, I bought the car with 160,000 miles, it a car for our son. We got the car cheap, and knew we would need to put a little money into it, thus we took it to Ahmed whom was much less expensive than anyone I got estimates from including the dealer.

@Unit_450

5 ай бұрын

egr pump?

Great job Ahmed! It always pays to check something out in more detail when what you find initially does not make sense. You are a true engineer and mechanic! 👍

Like how you said "Leaking coolant faster then the intro. That was rich

This is why you are a toyota master technician. One of my favorite yet. Other shows pre diagnose then film what they found.

This is channel will be at 1 million subscribers in a couple weeks. This is the fastest growing channel on KZread. Keep up the great work!

AMD, you are spot on with concluding why the pistons are steam cleaned. It's been a while, and then it developed into a more extensive leak. The Prius has an Atkinson cycle integrated into the stroke, and for a normal engine, that would not occur, but with the Prius, your conclusion is spot on.

@volvo09

5 ай бұрын

Yep, I was going to say does the Atkinson cycle have anything to do with it.

If they didn't improve these issues on the 4th gen, I'd rather stick to my 3rd gen. The newer car isn't as roomy inside and it's just plain ugly. I'm doing a "preventative" water pump, thermostat, intake, egr cooler cleaning, pcv valve and new egr valve (just like Ahmed told us to do!) in the hope I won't have to learn how to do a head gasket.

Exhaust blowback getting into cylinders is exactly what I was thinking once I saw the coolant coming out the pipe. But, with the cost of OEM Toyota Cats, I’m not sure how much better your news is LOL

Too bad no one here in Rochester has your honesty and knowledge

@orlandofigueroa100

16 күн бұрын

Rochester, NY?

Excellent work. You’re a patient professional mechanic and mentor. Thank you for sharing this experience with us. I learned so much!

AMD, I am confident the mystery will not take long to resolve and I bet 940,000 people agree with me. 😁

@donreinke5863

5 ай бұрын

Not that big of a mystery. Anytime there is a loss of coolant that is not external, that is not leaving evidence of coolant under the vehicle, the source has to be in the engine. Most V type engines (excepting "dry" manifold types) have coolant passages in the intake manifold, the gasketed joints where the manifold joins the head are a common source especially with plastic intake manifolds when manufacturers "went cheap" and stopped using aluminum or iron intakes. These leaks typically are into the oil resulting in the oil having a "milky" appearance. Far more rare are leaks through coolant heated throttle bodies (GM loved using those) and coolant heated carburetor spacers (Ford FE engines from 1958-70) The purpose was to prevent carburetor/throttle body icing in cold and humid conditions. Rare in the age of iron-over-iron engines, head gasket failures have become an issue because of aluminum heads, and the simple fact of physics that iron and aluminum do not expand and contract at the same rate, as a result newer types of head gaskets and the idiocy of torque-to-yield head fasteners have become common. EGR, whether cooled or not causes more problems than its worth, the intent is reduction of nitrous oxide in the exhaust, but results in lessened fuel economy, increased intake deposits and reduced performance. I definitely would delete the EGR system if it had the potential of leaking coolant into the engine or exhaust as it did in the video.

@ballzzinyourmouth8

5 ай бұрын

​@@donreinke5863fail

@JR-tl8tg

5 ай бұрын

@@donreinke5863 interesting, would this apply to the 2GR-FE RX350 mine seems to be losing coolant in small amounts but I can't find the leaks.

@donreinke5863

5 ай бұрын

@@JR-tl8tg This will be a long upload, but it is the diagnostic procedure I would follow. What I would do first is to carefully inspect the joint between the head and block as well as all freeze plugs in the block for any evidence of a white colored residue which would be indicative of a small and slow leak, as these are the most common locations for seepage/leaks after hose issues. It may require a mechanics mirror to inspect some of the areas as they are not easily able to be inspected, especially under/behind exhaust manifolds. This goes without saying....make sure your heater core is in good shape (not a common problem on Toyota vehicles) Also look under the oil filler cap and the upper part of the oil dipstick for any sign of a milky substance, which can be indicative of coolant leaking into the oil, but be aware that if you are in a humid climate that may be caused by simple condensation. If your throttle body has no coolant lines going to it (they will be small diameter hoses, most likely 10mm or 3/8 in) then it does not have a heated throttle body, and therefore would not be a potential leak source. Im in all honesty not sure about whether your engine has a heated throttle body or not as the engine repairs I have done to Toyota/Lexus SUV engines have not involved an issue of that type that could not directly be assigned to a leaking water pump. leaking hoses/radiator seams or a failed head gasket. Also be aware that the water pump is concealed under covers and may be seeping without obvious signs of coolant on below the vehicle, this issue I have seen and repaired on Toyota engines. If no leak has been detected at this point, removal of the spark plugs and inspection of the combustion chamber and pistons is the next step as per the video. If either have little or no carbon deposits that is an indication of coolant leakage into that cylinder, which is strongly indicative of a blown head gasket or cracked cylinder head.......However...... Toyota generally designed and manufactured cylinder heads which were thicker and more robust than most other manufacturers which helped to lessen head gasket issues, but failure is nevertheless a possibility, especially if the engine has ever been overheated. Ive done mechanical and transmission repair and rebuilding since 1972 on almost all vehicles..

@JR-tl8tg

5 ай бұрын

@@donreinke5863 This is by far the most thorough steps and explanation I've come across. Thanks for sharing Don.

Dear car care nut I own a 2019 Corolla with the 2,0 hybrid engine and had the exactly same issue. The heat Converter in the exhaust had a coolant leak. I live in denmark and been following you for quit a while. Keep up your great work on your Channel. I’m enjoying watching your videos a lot, as a Toyota afficonado. Greetings Erling

It's always fun saying to customers "I have to pull your windshield wipers off to replace your spark plugs. Sir, your Toyota is literally leaking exhaust fluid" 😂

A technician like yourself that has experience with the product as well as excellent deductive reasoning skills is worth his weight in gold! Excellent diagnosis and explanation of how you found the problem as usual. Way to go Ahmed!

It was very enlightening to see your careful step-by-step process and analysis in addressing this problem. Your narrative and explanation of what you were finding, as well as your expressions of curiosity at each step of the way until you arrived at a conclusion that could account for what you were finding, was both entertaining and educational. A great piece of detective work. Two Thumbs Up! 👍👍

I have a 2016 Toyota Prius that has over 240,000 mi on it. Have not seen it on that Prius holding my breath that it never happens. I have had to replace the water pump at 150,000 mi because it ended up failing on it, but other than that it's been a very reliable car

@antpart7998

3 ай бұрын

Figure out a way to monitor your engine temperature real-time with a Bluetooth diagnostic dongle or scanguage, at your mileage you may want to replace or clean your egr/exhaust gas recirculation as they coke up pretty badly by that mileage.

It's a common problem for cars with lots a mileage. We had this problem 2 years ago and Again and again. We seen a lot of this. Every Prius 2016+ have this problem. Also all Corolla and C-HR with 2 liters engine have this issue.

I knew right what it was from the beginning of the video. Saw one at the dealership and Toyota actually issued a TSB for these, they updated the heat exchanger pipe.

@SmileyBuddah22

Ай бұрын

Was it covered under powertrain?

You noted that coolant is used to cool the catalytic converter - you did not explain how that happens, nor did you explain the mechanism of failure resulting in coolant leakage of whatever it is that keeps coolant close to the converter. I do not have a clear picture of how all this happened. (retired mechanical engineer). By the way, you do an incredible job in these videos - I watch them all.

@Jack11527

5 ай бұрын

Coolant is NOT used to cool the CAT. It's the opposite, the CAT is used to heat coolant. This way, you reach operating temperature faster. It's just a basic heat exchanger. Once coolant is hot enough, a valve prevent it from flowing into the CAT.

@Jack11527

5 ай бұрын

Coolant is NOT used to cool the CAT. It's the opposite, the CAT is used to heat coolant. This way, you reach operating temperature faster. It's just a basic heat exchanger. Once coolant is hot enough, a valve prevent it from flowing into the CAT.

@Jack11527

5 ай бұрын

Coolant is NOT used to cool the CAT. It's the opposite, the CAT is used to heat coolant. This way, you reach operating temperature faster. It's just a basic heat exchanger. Once coolant is hot enough, a valve prevent it from flowing into the CAT.

Good and Bad news for the owner, I usually associate Prius Head gasket issues with the morning death rattle and will always throw engine codes for misfire and rarely use that much coolant in one day. That cooler is a known problem on the 3rd gen Prius, I just worked on one this week. Good to know that they still have not resolve on the 4th gen.

@ 16:20 ..... AWWWW MAN.....all that pink coolant all over your nice shiny garage floor 🤣🤣

Great diagnostic job! Finding out what the problem is BEFORE taking the engine apart, thereby having to take extra time, and costing the customer extra money. I wish that there was someone just like you here on Oahu. If there was I would definitely give them my business. Please continue to make these awesome videos!

@zerogravityindicator

5 ай бұрын

LXS Hawaii is great. They're on Punahou St. now.

AMD, you are ONE OF A KIND! Your knowledge and patience is simply legendary!!!

"Your exhaust is leaking coolant!" 😂 Don't forget to fill your blinker fluid too!

@dlbrent7472

5 ай бұрын

But the Prius has a coolant heat exchanger inside the catalytic converter that helps warm the engine faster. It is actually inside there.

When my 1999 Camry 5S-FE blew its head gasket a couple of years ago, gas bubbles were pushed through the cooling system and became visible in the reservoir.

AMD, these cars have a tube that goes from the caralytic converter to the EGR and the gases reburn into the chamber. In this case the coolant is going to the chamber through the tube and EGR.

@kosta16auto

5 ай бұрын

That is also true. That’s why if catalytic converter on those Toyota engines gets internally destroyed the small dust and pieces get returned into it the cylinders and from there destroy the engine for short time.

It IS a common gen4 problem and many simply bypass the coolant lines at the cat. Often reported on Priuschat.

Same exact thing happened with my 2017 Two in June. We were driving home at night and the wife was cold so she turned up the heat. Never got hot, then the warning light came on. FIL is a Toyota tech, so I took it to him the next day and he said it was this issue. Good thing it was a warranty job because CA…didn’t want to see the bill on that one lol. There’s also a TSB on this issue, and a replacement that supposedly fixes the issue, but it’s only to be completed when the issue shows up, which is a bummer because this could blow the engine if someone isn’t paying attention to the coolant, like myself, and who doesn’t have anyone to take it to right away.

I am 82 years old and do EVERYTHING MYSELF EXCEPT TRASMISIONS.If I lived near you ,I would relax and have you do ALLof my work. You are a true craftsman

@riceburner4747

Ай бұрын

I'm 71 & feel the same way. I hope I'm ALIVE in my 80's.😂 Let alone, still get underneath in my driveway. But I will do until I can't. 😉✊️👍🖖

No wonder this fellow has a million subscribers. Diagnosis can be the hardest part of the job. No Captain parts cannon here.

No underbody drips and profuse coolant consumptions sounds like it's been perpetually followed by a white exhaust cloud for a Looong time. One would presume cracked cylinder wall if there's no puddle, but I'll stick with this to see the real cause. Add: Well, that's different; My next guess would be the EGR is sparkly clean. Sure didn't know about the cat being a heater for coolant though. "Your cat converter is leaking coolant." Sounds like blinker fluid. 😁

Crazy engineering equals a crazy problem. Great video.

Regards from POLAND ; Master Tech

I got a 2015 Prius with 133k miles and runs excellent. Great mpg & cheap maintenance. Can’t complain

AMD doing his best Sherlock Holmes. Great job - I hope it works out for the better for the customer.

As a master tech at a NY dealership I can say I’ve seen this problem on a bunch of 2016-2017 Prius’. I believe Toyota has issued a TSB for this issue

@riceburner4747

Ай бұрын

So what makes them GO bad? Poor design? Are replacements better made?

One of your best videos yet, hats off. I always learn something new watching you videos, even having 30 plus years of experience with mechanical gadgets. Now could you not just bypass that system to complete some testing in the rest of the engine and find out if its working with no problems?

@sldghamr58

5 ай бұрын

I was thinking the same thing. I now want to get under my Gen 3 and see if i have the same system

Any chance that catalytic converter is covered by a manufacturers extended warranty for an emissions device? 10 years, 100K miles?

@jduran111

5 ай бұрын

Good question. What to know too!

@riceburner4747

5 ай бұрын

The heat exchanger IS covered under warranty if you are within the time span. If not, u can bypass the cooling lines in two ways.

You are just the best. The world needs more people like you!

“Well, hello coolant.” 😮 What a headache!

Wow! Your customers are always in good and honest hands in your shop

Love that chuckle you did when you saw the unusual scenario of coolant dripping from the exhaust pipe. I can tell you love what you do

I learned something new today, cats and coolant do not mixed. Nice video

My favorite episode yet , love your solution process , thanks for taking us along. 👍

You are honest mechanic ,you could have had the customers pants down 💰💰saying it’s head gasket 💰💰hope your honesty gets rewarded 👊🏼

You followed your gut feeling and it paid off. Great video.

Thanks for walking through the diagnosis and problem-solving process, especially when you ended up with something unexpected!

Things are not always what they seem !!! Great detection !!!

Great job Ahmed. Nice work finding that problem.

I enjoy witnessing your process of seeking answers to your inquiries-it reflects the meticulous approach of scientists, never making assumptions. Fantastic video on accurate diagnosis!👍

Fantastic diagnostic. Great Job!!❤

AMD, thank you for your amazing and thorough content. Your high level of integrity and honesty is a blessing. Wishing you and your family the best!!

Actually received a recall letter on my KIA NIRO HEV for the same issue! My coolant has been dropping very slowly during summer days and when I mentioned to the advisor he said that a same model came in and was losing it daily and found all of them went into the catalytic converter!

Excellent diagnosis Dr TCCN!

There was a TSB some time ago to replace that catalytic converter pipe. The coolant runs past there to accelerate heat up since the engine doesn't run under certain conditions.

That was an interesting video. I like the way you diagnose these problems and always have the interest of the customer in mind.

Very good call ccn.!! A master at work!!!

Let’s get a video of your experience as a shop owner! I appreciate your perspective.

21:00 attkinson engine. holds open the valve longer and sucks in some exhaust. i like this

One of my favorite diagnostics videos thus far.. another was an old video from “Pine Hollow Auto Diagnostics on an Acura MDX.. and the finding was a total plot twist just like this one… Thank you always for sharing with us.

Awesome analysis and thanks for walking us through your reasoning for why this might not be a head gasket. That's definitely something that could be missed if someone would have gone immediately with the head gasket replacement.

I have a 17 Prime, was sweating for a minute lol.. Great informative video, thanks.

I’m a Kia Technician in ONTARIO. We have the same common problem in KIA NIRO. The moment I read the title, I knew what it is gonna be.

And this is why you are a MASTER tech and I watch your channel. You figure out problems and don't just charge the customer. To bad you in Chicago area and not by me.

Wow! That was a crazy find!

Great diagnostic!! I would wager that the average shop would have done as you mentioned. Seen the steam cleaned pistons tops and sold a head gasket replacement job and then been faced with the cat issue! We so many more of you, Eric O, and Ivan’s in the world of mechanics. The public also needs to understand that in this day and age diagnostic time is money well spent. Great diagnostic. Wish you and your family a great new year.

Another great educational video. You are so appreciated ❤

Excellent troubleshooting/diagnosing video. Thank you 😊

Very interesting indeed! I love it that you take us along before actually figuring out the problem, no staged "voila" diagnosis. I can't believe the exhaust/cat is cooled also, holy crap. so envious of your critical thinking/diagnosis, that cylinder scope is invaluable. Everything you said made sense, even though the problem was not making sense. Easy to understand why many would just "jump on" the head gasket diagnosis/job. What a sinking feeling when they restarted the car after the head gasket only to note the smoke. Would be even worse if they let the customer take it only to have it return the next day with an upset customer. Don't get me wrong, we have all stumbled and made errors, but this would have been a big "ooooops" for sure.

Well done . Outstanding investigation.

Just found your channel. Love the way you tell the story

Love this video and your content as always. Very informative and interesting. As a newly learning toyota Technician, this is extremely helpful and useful. I'll keep this in mind whenever I look at a 4th Gen prius. And you're absolutely right about trusting your gut in diagnosis. I've worked with a few techs who literally just guess and hope they're right, and usually, it backfires. Again thank you so much for your honesty and straightforward approach. It's very helpful and encouraging.

Excellent presentation. Thank you. Gen 3 original owner 2012 Prius with 280,000 miles. So far no head gasket issues. Fingers crossed.

Great diagnostic work Ahmed, that is why you are a Toyota Master Diagnostic Technician. The owner can park that thing in Chicago overnight and someone will remove that catalytic converter with no charge 😁, got to love Chicago.

If it is considered an emissions device then Toyota's warranty is like 80k miles in non-CARB states and 150k miles in CARB.

I was literally sitting on the edge of my seat here. It's like watching a suspense movie. When the Dr says he doesn't know what's wrong with you. But the good news is whatever it is, they are going to name it after you.

I believe there's been a bulletin on these for a WHILEEEE now

I’m glad that this engine isn’t a head gasket issue, but what is it with Toyota engines and blowing head gaskets?

Great troubleshooting and great videos thanks!!!

Great dogged determination to come up with the correct diagnosis!

Thank you. What a relief that it is not HG issue. I have 2018 Prius Prime that is suffering from the similar issue at 170000 km. It smokes white once in a while but runs great. The coolant loss has been manageable.

Reminds me of my Buick V-6 intake Coolant leak. Took me a while to find that problem!

Well done once again.

I had no idea that coolant pass through the cat to heat it up, wow, i would totally miss somethig like that, like you've just said, white smoke , extremely clean cylinders, head gasket, and i would be wrong, thank you for a top notch class on the prius, i loved it

Hey 👋 from Kenya 🇰🇪

As a mechanical engineer, what I know about that is the philosophy behind those synergic engines have been remain the same up until now since they ever came out. So as long as the engine cranks up and shuts down constantly in a typical city traffic, accordingly contraction and expansion will continue to occur until the parts such as head gasket in this case will get fatigue and it will no longer seal perfectly and eventually fail. In a nut shell, Design engineer behind this engine need to keep engine's thermodynamics at constant temperature to annulate this issue for a long time.

@18_rabbit

5 ай бұрын

would love more expansion on this topic! thx!

@sunilayya8948

5 ай бұрын

I always suspected this issue with idle stop engines which undegoes Temp fluctuations. Thank you for clarifying this.

@user-ts7lu6xp4w

5 ай бұрын

would have thought big failure rate but there is not. As the tech said,dont look for the obvious.@@sunilayya8948

@blipco5

5 ай бұрын

I never thought about that but it totally makes sense. I figured starters wearing out and oiling issues but these engines seem to last big miles.

@WIP0

5 ай бұрын

@@blipco5 Thanks for dropping your comment here. Everyone can imagine what fatigue is right if you have a piece of sheet metal or aluminum in your hand, when you keep twisting it I will eventually become plasticized and split apart. The breaking force is in this case; the heat. This is a basic example from material science. Whereas in common internal combustion engines, they come up to a certain heat level such as 180-200 F degrees. So it keeps itself in that range so that constant heat changes like turning on and shutting down does not take place like that of synergic engines (hybrid engines). I hope that this makes sense.

thank you for sharing. This was one of my favorite ones!

Great video on proper diagnosis. I love watching you getting answers to your thoughts. Its the way scientists work. Never assuming anything. Only fact driven 🥳

This is one interesting video from all the videos that I have watched from AMD! Thank God I don't have a Prius!

Kudos on the ability to objectively assess the available evidence gathered and not jump straight to a conclusion, especially in front of a rolling camera!

As you were diagnosing the coolant leak with all 4 cylinders clean my question became what is common to all cylinders. Did not expect a leak in the exhaust but back pressure from the EGR made sense. Good diagnostics.

I thank-you in advance for also posting the repair video...I suspect it may be in the whelm of us DIY'ers as long as we don't have bad rusty bolts in the undercarriage area!!

Thanks for the video as always, excellent job . I had a similar problem with a Toyota Corolla , every dealer I took it, they all gave me a different diagnosis. I had to sell it because that engine light, never when out and it couldn’t pass inspection. I wish I had you as a mechanic. Thanks again excellent job.

Great video as always.

Amazing diagnotics and logical skills AMD, you sir are the SHERLOCK HOLMES of automative service, thank you for taking us on another wonderful journey. God bless!!

I had the exact same problem on a 2013 HiHy, and yes it was mysterious until it made sense! The slightly sweet smell from the coolant running into the hot exhaust is also misleading because makes you think about head gasket.

Great Job Ahmed.

Great info..! I'm sure most of us will appreciate knowing this before replacing a head gasket just to find out it didn't fix it ..! Can you imagine! What do we tell the customer? Thanks again for this very helpful video.

Good job, you should be proud that you kept going and found the correct problem