In this video I show you how to use the Pico Scope to not only find out your vehicle has a blown head gasket but it will tell you the exact cylinder(s) that is having the problem. Why is this important? It is best practice to grab all the data you can before you tear the vehicle apart so you know what you're looking for in the case where it is not obvious.
-Enjoy!
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Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.
-Enjoy!
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE: https://www.patreon.com/southmainauto
CHECK OUT OUR "SMA SWAG" STORE! Go on Teespring and get your very own SMA merch!
https://teespring.com/stores/the-sma-store
If you don't like Patreon feel free to use the "PayPal Me" link: https://www.paypal.me/SouthMainAuto
The South Main Auto Amazon Store:
https://www.amazon.com/shop/southmainautorepairavoca
AES Wave Automotive Diagnostic Tools: https://www.aeswave.com/cart.php?m=affiliate_go&affiliateID=2525b91fc8e906e8215984074c9d9e8f&go=https://www.aeswave.com/Miscellaneous-p9347.html
Thank you for all the continuing support!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.
I miss the videos where we went to junkyards for parts
Easy peasy. Do a block test. If the blue turns yellow then you know.
I devised a lower tech version of this head gasket test and never had it fail me.
Back in the day, we’d yank all the plugs out, put the cooling system pressure tester on the radiator, pump it up, wait a while , then bring a shop newbie over to watch the spark plug holes while we cranked it. Needless to say, our shop newbie got a shower.
That test was somewhat crude and not terribly conclusive, as the differential pressure between combustion chamber and atmospheric was only about 15psi. II found that if I took all the plugs out, filled the radiator neck until it was starting to spill out, took one of the plugs and put it back in and cranked it. Now the differential pressure between combustion chamber to atmosphere could be 175 psi, making even a slight gasket leak show up, and would cause the radiator to overflow, as the combustion gases were being pushed past the gasket. If the radiator did not overflow, yank the spark plug out, and put it in the next cylinder and crank it, repeating the same test cylinder by cylinder. Left all but that one spark plug out to allow a faster cranking speed.
Signed,
Brad
5-time re-certified ASE Master Tech
35 years now behind me (now retired)
Pico training was so interesting and cool and we were so pumped to use our newly taught skills. And 10 years later, I've only used it twice and I don't think it was even necessary. Most tech maybe used it 1 time after training. Even our foreman use it mainly to document reading for the factory engineers to look at.
Most electrical diag is done by checking for known "good" power and ground and if so, it must be a bad electronic part.
For ignition work, we just mark and swap parts to see if the problem moves. For headgaskets, we just pressurize and use the scantool to see which one is misfiring and then borescope it to confirm.
Even for hybrid system, I've yet to use Pico to diagnose concerns. It's mainly an engineer thing. We don't have access to the array of known good graphs and simply don't have the time to produce known good graphs on every part of every model vehicle.
Even Scanner Danner had Pico diag lead him astray. He had a nonideal graph causing him to prematurely condemn a part when it was something else. Pico is a slippery noodle indeed.
This test should best be performed with one in cylinder 2 and then only 1 in cylinder 1 to actually see if they as well are giving pressure. The method you used did not prove they are not leaking by.
I’m always learning newer and better ways to use my pico scope. Nice Job on showing us this diag method!
Sorry – plug, not bank…
Jad a Camry 5S-FE that drove well all the time, but lost coolant quite a bit.
New radiator didn't fix it.
Head gasket, (after about a year), got done.
S
Want to say that generally the plugs get washed when the HG goes.
Good on you for checking the other bank.
REMEMBER BROTHER, YOU ARE SUPPOSED TO BE SHOWING PEOPLE'S HOW TO DO THIS WORK WITHOUT ALL YOUR FANCY TOOLS! IT'S SUPPOSED TO BE FOR THE AVERAGE GUY WITHOUT THESE FANCY EXPENSIVE TOOLS BROTHER! WHAT HAPPENED TO THAT?!??!? LOVE YOU BROTHER. 🙂💖 BLESSINGS.
In these cases, if need to keep on the cheap… KSeal Ultimate generally takes care of the “sipping” of coolant
Hiya Eric
C'MON BROTHER, YOUR GOING THROUGH ALL THIS NONSENSE WHEN YOU ARE SUPPOSED TO BE SHOWING THE AVERAGE GUY HOW TO DO THIS BROTHER. TAKE OUT ALL THE SPARK PLUGS AND DO A COMPRESSION TEST! IF 2 CYINDERS ARE CONSISTANT LOW COMPRESSION, YOU HAVE A HEAD GASKET LEAK! C'MON MAN! 😁
Welcome back the Self Made Auto Channel. Makes me laugh every time.
Hopefully it IS the Gasket and not the Head or worse yet The Block .
Hi Eric you have done it again. Taught your audience a valuable lesson. You really underestimate your talent for simplyfing what could be a difficult concept to understand. I expect the driver does not frequently drive long distances at Highway speeds 2 hours or more. If he did I would expect he would have temperature issues showing up. Keep up the good work. I just wish I could do it because you can do it.
Great diagnostic. Please do share with a quick follow-up video if the head gasket shows the leak channel and if there is a difference in piston top appearance between the leak and non-leak cylinders. Thanks!
For many years I used an old compression Tester that worked great
Ya thats a cool tool I believe they also make a head gasket leak test kit, it's a dye thing that tests for exhaust gas in the coolant. But you pin pointed between 3,4. Now you know exactly where to look, Nothing feels more wrong than unbolting a head and you can't find the blow out. . Love your way of going about things, let's now hope it's visible and not a Crack in the cylinder or head! Hope we get the k series head gasket video.
I'm curious as to how this happened? Stuck thermostat? Blew a hose and kept driving? Water pump going bad?
Great test. I guessed 3 and 4 too. But you had it dead on. Grest work. How many miles on the car?
Could the pressure build up have been seen with just a cheap pressure gauge? No need to have a transducer and Pico. One psi should be visible.
The building AC says show the head job. Subaru does it too.
Want your opinion on gaskets.
Knowing which cylinder that is leaking is a necessity when the engine has 2 banks unless you are going to do both head gaskets
You don't have Ivans pressure transducer?
I don't know where the coolant passages are but maybe by the exhaust valve?
As soon as you showed the graph for number 3 I figured it is leaking between 3 and 4 and I guessed right. Great job ! It is to bad all mechanics aren't that thorough in their diagnostics. Maybe they don't want to or maybe they don't know how. I came across your website looking for a problem of my own after having my 03 Chevy stall while pulling my boat. that was my fuel pump connector. When I did the fuel pump I noticed my power steering was having issues and installed a new pump. I drove a 100 miles from home and the truck died in the middle of nowhere and had to be towed. I searched and searched and came across your website and found a video about a truck intermittently stalling after replacing the power steering pump. You found it was a bad ground for the ignition coils that grounds to the block near the power steering pump. That was my problem and I thank you for the solution. That happened last year and I have not had any more issues.
Nice piece of work!
That can be important on a split engine like a subaru or other v type engine if time or funds only permit only doing one side,
Show us the head gasket tear down and replacement. That would be a cool video!
Assumption without taking engine apart. Pulled many heads finding a head gasket was sealed and there was a crack in a valve seat/water jacket. Yes head gaskets are the most common culprit!
Have you ever tried this with a rubber glove and rubber band?
Voting NO ON EVERYTHING and yes on nothing sends the only message that WE are tired of INFLATION!!!!!!!!!!!!!!!!!!!!!!
Seriously impressed with your level of investigation. Back in the 70's world of flat rate mechanics it was strip it down, replace everything you see , give the customer the bill … Welcome to GM !!
You see this way more than this keyboard warrior, but I'd like to see a follow up on this to see what the pistons look like. Quite often, a compromised head gasket will steam clean the pistons. I wonder if there's any evidence of this?
This is great. Peco is an amazing tool. But if you don’t have a peco this could also be done with a pressure gauge
Simpler way is pull plugs, look at insulators. Cleaner, whiter will be cylinders getting coolant in them. Pistons will be cleaner too, which you could see with a cheap endoscope.
i think you were very clear on this 3 and 4 leaking and 4 was the worst one hard for me to see how anyone else could see different
How about trying to find if compression loss on a cylinder is from a valve problem or a holed piston without sticking a camera down the plug hole or removing parts?
The evidence leeds you to the problem
Nice diagnosis
Awesome diagnostic procedure; you wouldn't possibly have a clone down here in Georgia, would you? 🙂
Keep up the good work; love your videos…
Myself, if it is a head gasket that is gone, Head has to come off anyway, Im going to see where the blow is as soon as it is off. But it's cool to figure it out first.
Is there a national database of diagnostic techs?
It would be great to have you or Ivan to work on my truck…
But I live in Asheville NC … I also know there's no listing here for diagnostic services
Well one guy says he checks BMWs
I used to run the car til warm -let it sit awhile -pull the plugs and crank it-you will see a mist come out from the blown cylinder.
What if the head is cracked, and you quoted the customer for a blown gasket?? You will still have to disassemble it to verify the issue. Great vid Eric.
Could you so this with a coolant pressure tester? Remove the fuel injector relay
Very nice tool, Eric. I just watched Ivan at Pine Hill using his scope. It seems that electronic test equipment is necessary for the up to date shop to do testing. Thanks!
Honda Quality!
Hey Eric thanks for another great informative video, is this test possible without the pico scope? I have a vantage pro and was wondering if it’s possible to perform the test with it.
Take us along on the head gasket repair, it’s been awhile since we have had one 😁
I had a similar problem with my pathfinder leaking head gasket on the exhaust side no milk shake no drivability issues
Only found out one day when my wife seen a puffy white cloud on a cold start then car rlran perfect dealer warranty the work only after leaving it over night to have them do a cold start. Was told it leaked after shut down and car sat once started and warmed no leak. Weird issue but glad my wife caught it before warranty was up.
You are the man
Next video…a head gasket replacement?!?!?
Awesome explanation. As always very thorough. Thanks Eric.
This is the typical way Honda head gaskets fail, between cylinders and water jacket. Seen it a bunch on the J35 V6 engines, especially cylinder 5 for some reason. As it worsens, it will have a cold start miss/stumble until the coolant is burned out. Pressurizing a suspect cylinder with a cylinder leakage tester and observing radiator bubbles is my go to because I'm too cheap to buy a pico and WPS. 😆 Cool demo of the WPS though. I may someday pop for that stuff. Only scope I have is the uscope.
That's a cool test, I can't wait for my next suspected head gasket now.
Nice job
Eric, you have a good head for head gasket woes !!!! No exterior leaks, no antifreeze in the oil, no water vapor exhaust – so must be internal leak is a reasonable assumption. I would agree. Plugs look good, no antifreeze gushing out of the spark plug holes. Now 99% confident to take off the cylinder head and see what is happening. Waiting for part 2 – The Tear Down !!!! Brewing a new cup of chocolate cherry coffee in my Krup's single machine. I'll get a 8 piece of mixed chicken at Walmart and I'll be ready on my Lazy Boy recliner !!!!! Bring it on !!!! 😀👍🍮🐔🛠😺
Love your diagnostic process although would it have been better to start by removing all the plugs at first, then installing them one at a time. I believe the difference is when you pulled the first two sparks individually out, it had no effect on the pressure on your test. Does that really eliminate those cylinders? By taking all plugs out in the beginning, it would show no pressure build up as you showed when you had all the plugs out. Then what you could do is start by putting plug #1 back in to see if there is a pressure build up. If not, then put in #2, then #3 and so on. By doing the test in the opposite manner as you did, you truly didn't prove the cylinders number 1 and 2 were not also an issue. I'm I wrong in my assessment?
using a coolant system pressure tester would work also, just connect it and crank the engine instead of pumping it up, same result with the gauge reading pressure that shouldn't be there and a whole lot cheaper 😋
what happened to Roger
head gasketngets replaced and shortly after the dreaded P0420 starts screaming. lol
I remember back in the 90’s my sister had a ford escort. The cooling system was getting pressurized enough to send a geyser out of the radiator about 4 feet 🤣
4 minutes in its called STAIR WAY TO HEAVEN….or …ESCALATOR TO ENGINE HELL
Area 51 needs a good mechanic you up for it
It's too bad they don't pay teachers crap, you'd be a good one.
Pico on a radiator cap?? 🤯
Seemed pretty clear from here.
great demo and my added comment is, this is fantastic when you've got 2 banks. I had a V6 impala in 3 months ago – owner wanted me to "only" replace the front head gasket as he'd already had the rear one done. I used this test and was able to prove that while he did need the front head gasket replaced, with 100% certainty I could claim he also needed the rear one done too. This type of data is irrefutable .. and makes me feel soo good about calling these repairs. Awesome vid!
Never even thought about doing it this way, great job like always Eric. The new way I recently learned is to pressurize each cylinder with the radiator cap off until you have a fountain from the radiator.
wouldn't white smoke be coming out the tailpipe?
Eric, just wanted to say thanks for the videos. I've been a mechanic for 6 years. Got hired with no prior practical experience and you have taught me so much. Funny, I finally seen my first failed headgasket today.
Thanks Eric O I Another use for a tool in the arsenal.
I have been a mechanic for many years and I always find out what cyl is leaking before taking off the head makes it easier if you know where to look first
Don't forget,you do this every day as well.
I’ve been testing a DV350 fluke pressure transducer attached to my scope to see if I can get good readings from it, should work for this test too, nice to know for sure where it’s leaking.
I like that tool T shaped spinning quickly to undo bolts…What are they called?
Wow that was awesome. Now how much does this tool cost?
I don’t know if I missed anything, but why is it necessary to know where the gasket has failed beyond it simply failing? Isn't the gasket all one part that would need to be replaced anyway, regardless of where exactly it has failed?
Now that's an interesting procedure. Thanks for sharing!
"I'm not real great with the scope"
…says the guy who taught me how to use a scope.
Mechanic mindset is a great picoscope channel if anyone is interested
Now I use a lot of hand tools over impacts and such on many things but the amount of t handles and such you use that could be sped up amazes me lol
Being in a shop myself; time is money. I personally don't see a point in knowing what cylinder is leaking when your about to rip into it for a head gasket. Especially on a 4 banger. It's fun to be absolutely sure it's a head gasket that has failed but going beyond that is kinda pointless. To address your comments on it not showing more of the classic signs of a blown head; it's not a big enough leak yet. It was caught early. Your meter only read about 1 PSI of pressure during the cranking phase. You would need a lot more then that to blow into the coolant to actually see anything. But good video as always Eric O!
If you get the job, will you show us please?
I got into this business because troubleshooting technical issues logically is the one of the main things my brain can do and loves. Watching your videos reinforces and builds on a lot of the stuff I learned in school and on the job so far. I'd even used one of your videos to diagnose a faulty ignition switch during some on the job training. Once I realized that everything that wasn't working relied on the ignition switch's status, we plugged in the scan tool and voila the status was super sketchy as you turned or jiggled the key. Sometimes it's the simplest of tests with a bit of know-how.
Awesome stuff! Glad to see you showing this method! I personally have never pulled the plugs like that to confirm. It certainly does require some more analysis, but I use a first look delta sensor, a trigger off a coil or plug wire, and then I overlay a piston chart made by “the drivability guys” to help analyze the waveform. I’ve probably confirmed head gasket failures a half a dozen times now this way, and I can say that only once was it just 1 cylinder leaking. Thanks Eric!👍✌️
Excellent diagnosis….thank you
Great explanation, Can’t wait for the tear down video
Sheesh! I thought all the really stupid commenters left your channel ages ago. but they are clearly back today. Your video was very clear about what you were doing and why. The majority of comments shows that people either don't watch the video or don't listen to it. Don't let the idiots get to you, Eric!
Eric O. good job explaining this buddy appreciate it .Are you going to do a video fixing it ?
I was hoping you were going to do the test with plugs 1 & 2 in to further prove which cylinder(s) are leaking. Great diagnostics Mr. O!
Atlas
That's about what my 1982 Ford Escort used to do. It didn't actually have a blown head gasket. It had a crack between cylinder 3 and 4 that involved a water jacket. It was burning antifreeze. The only complaints were that you literally filled the antifreeze and checked the gas, and that you could smell antifreeze in the exhaust and even when it was just shut off and parked. It started and drove fine. And I do know exactly what was wrong with it, because I helped to tear it down and saw the crack. The head and gasket were fine. As it transpired, this was a common problem with that 1.6 liter engine, and the reason they stepped up to the 1.9 in 1984 1/2. They used the timing belt to drive the water pump, and when the water pump got tight with age, it would strip the teeth off the timing belt and bend the push rods. Once they were bent, the engine would still run (sometimes), but it would run hot. They had cut so much weight out of that engine to meet fuel mileage standard, and had cut the cylinders so thin that once it started running a little hot, they would crack. Between 3 and 4 seemed to be the most common spot. We had to start every wrecked Escort and Lynx in about 3 junkyards to find one that didn't have the same problem and didn't steam.
Cracked head?
Ive said it many times on here This is what separates the reputable shops from the not so much. Diagnostics at its finest folks.
Would a test for combustion products in the coolant have been useful in this?
Good test, wouldn’t a leak down test be just as effective? (I don’t own a scope)
Wow that's a great easy way to figure out if you got a bad head gasket nice, I like it👍👍