Here is the playlist for the rest of this series:
https://www.youtube.com/playlist?list=PLAFYVCyenqcoTvkbvE6avGuLJOQnFcx4Z
My apologies that I did not upload this sooner.
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium right here on YouTube. There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
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Great find Paul brilliant work
Good to see this. Thanks Paul.
So how does one that’s looking for a used h3 detect whether the ones you’re
looking at have this issue?
What should you expect to pay to have a new and better head installed with
new valves and springs?
Are weak/cheaper/poorly designed valve springs ever part of the issue?
This is not a correction that could typically be made by a non mechanic,
owner probably ?
I wish you could have colored the valve with a black marker ..put it back in the head ..and spun it around and pulled it back out ..would have shown how the seat meshed with the valve
Nice I had the same problem before I Found the problem valve sits there is a TSB I like all you r videos I learned a lot from you thank you scanner danner
Too little cooling in the center of the head. Wall between intake and exhaust overheated and warped resulting in the non contact area. Design has a metal fin between intake and exhaust without a proper thermal path to the coolant.
fuuu, thumbs up for not giving up!
Wow… That’s awful! I’ve never seen anything like that! That is not normal wear… I suspect that there’s a valve (non)rotation issue, and the carbon buildup on that valve makes me think it’s involved, too. That’s pretty much not repairable, either. That’ll need new seats. Ah well, time to pass it off to the Engines department! Have ’em knock down that god-awful machinist ridge, too; give yourself some low-lift flow. 😀
To add some accuracy to the test i will connect a leak down tester to the cylinder when creating the valve leak and bring it up to the same 70% we seen on the Hummer
Nice
Good to see the conclusion thanks for posting. I had a chevy colorado with the same 3.5 motor that had similar issues eg slightly eradic idle, misfire codes that were only intermittent. The truck only had 88k so I sold it fearing it was the dreaded and common valve seat issue.
was the conclusion of that GM valve problem that the stem was too weak and some of the valve found a resonance and oscillated?
so I suppose if we follow the rabbit down the hole. Long term it explains why these engines eat up catalytic converters. Because if the intake(air/fuel)valve is constantly bleeding air into the cylinder that’s going to make it run lean, and lean means extremly hot exhaust gas, excessively hot exhaust means melted converter, broken exhaust manifold bolts at the head, ect.. It all makes sense now. Thanks scannerdan, great series, subscribed!:]
great vid. mine is in the dealer as we speak… mine was leaking oil up through the breather hose in back part of the engine that goes to the airbox. sounds like a minor fix right? lol
I was wondering if you pulled from a correct cylinder, to compare the valve seat…
I had to watch the video twice, but everything you worried about showing up, showed up. Thanks for sharing.
Wore plum out
All those 3.5/3.7L motors had head problems. I remember when we would get those in on trade they always ended up at GM getting the head replaced under warranty lol
diagnosed a bunch of those valve problems, good to see the tear down
Im wondering if the Valve Springs were the root cause maybe causing valve float and burning the seats. Hence the bulletin says to replace the springs as well.
what was the total costs of this repairs?
The seats are burnt.
thanks Paul, it`s wonderful series.
Great videos Paul! Many thanks for all your effort! It seems to me that the valves are also slightly bent, caused by an incorrect heat distribution along them, for using a “not so great quality” material…maybe? Just a thought. Anyways, keep doing what you`re doing man, you really are a very good technician and a great teacher too. Thumbs up!
From what you’re showing here, it looks like the valve seat was not ground properly in the first place – manufacturing fault?
@ScannerDanner for president
Was this the final conclusion to the RTI Hummer you brought into the classroom last year? Did this video get lost or did it just take that long to find the valve seat problem?
Hey Paul.
I just watched all the Hummer series over again and Cook particular interest to the maf sensor waveform. For the exercise i am going to perform the tests using my Pico on a known good vehicle that has adjustable rockers and create inlet leaks and exhaust leaks and compare them with valve sealing properly. I will recharge the battery between each test (although proberbly not neccesary) to eliminate any variable cranking speed. Hopefully the tests will give us good direction by being able to compare the same cylinder in various conditions. I will email the results to you when i have done it.
Regards.
James
did you rebuilt the head or did you buy new one gm has update head with harder valve seatsreason I was asking you mind at dealer now they want do valve job on it
I see that all the time on those soft MAZDA heads. They get a hot spot and the alum sags in that area causing a leak. If that area cleans up last when you cut the seat that is pretty much the same thing
Very nice, them look like hot spots in the seats that caused the valves to deform the seats. Seen that several times.
Two weeks ago, I fixed a 2006 Hummer H3 with this exact same problem. I noticed that there is TSB for this problem. By watching your videos, I felt very confident performing the job. Thank you ScannerDanner.
When are H3 owners going to file a class action against GM, I and many others are having this problem and it dont look that easy to fix.
I just purchased your book spent $117 I didn’t have it better be good my friend!!!
Gm has a recall about the head issues on the H3 with the V6. They all crack or they have valve issues
took not cook 🙂
just had the head replaced by a chevy dealer they said #2  wasn’t seating properly charged my 2600 had my truck over a week got it back still feel a vibration in the truck when sitting at idle any thoughts on what it is? dealer told me it’s an 06 not a 2017 lol
That small amount of wear caused a big headache! Nice work
Very good shots of the seat wear.
I can see it, thanks for the info.
thanks Paul
Paul was the valve and seat distortion a cause or a result of the misfire. Your engine professor that was involved in the case did he have any thoughts after viewing the valve and seats ? That was an awesome series .
Was this vehicle using E85?
just had the head replaced by a chevy dealer they said #2  wasn’t seating properly charged my 2600 had my truck over a week got it back still feel a vibration in the truck when sitting at idle any thoughts on what it is? dealer told me it’s an 06 not a 2017 lol
That would turn me insane trying to discover the reason for this misfire. I have a question though, such valve seat damage didn’t show in compression or leak down Tests?
Paul, awesome to see physical, tangible evidence to back up the high tech diagnostic evidence ! Even a year later ! LOL !