Broken intake valve at 113,000 miles

[Esko07]

Hey all! New member here and I really appreciate all of the threads on various issues. Has helped me tremendously on previous repairs.

I have a 2007 Escalade AWD with the 6.2L. Recently while getting on it and accelerating on the freeway the engine straight up popped and had instant loss of power. Check engine light flashing and stabilitrak came on right away. I drove it another 1/2 mile barely to exit and parked it. Towed it home, scanned it and only had P0300 (random misfire), and instantly compression tested it. All cylinders were great and over 160 psi but cylinder 3 was dead 0 psi.

At this point, I figured a broken valve spring. Took off valve cover but instead I found broken intake valve on the stem right by the retainer clip! Couldn’t believe it. Maybe it was caused by valve float? Or did timing jump? I can see where the piston hit valve but I got lucky and no sign of damage to piston visually. Valve was of course bent though.

Truck has 113,000 miles and has had Mobil 1 synthetic oil change every 4,000 miles. Truck has been pretty reliable in the last 6 years of ownership. Took the head off and it’s currently at machine shop getting all new valves, seals, and springs put on.

My question is what do you think caused this? Should I check the camshaft, timing chain,
replace oil pump, camshaft position sensor, actuator magnet, etc?? I’m a little strapped for cash so trying to make accurate repairs myself but don’t want to re-assemble just to have to break it down again. Any help or similar situation would be great!! Thank you all.

 

[Geotrash]

Hey all! New member here and I really appreciate all of the threads on various issues. Has helped me tremendously on previous repairs.

I have a 2007 Escalade AWD with the 6.2L. Recently while getting on it and accelerating on the freeway the engine straight up popped and had instant loss of power. Check engine light flashing and stabilitrak came on right away. I drove it another 1/2 mile barely to exit and parked it. Towed it home, scanned it and only had P0300 (random misfire), and instantly compression tested it. All cylinders were great and over 160 psi but cylinder 3 was dead 0 psi.

At this point, I figured a broken valve spring. Took off valve cover but instead I found broken intake valve on the stem right by the retainer clip! Couldn’t believe it. Maybe it was caused by valve float? Or did timing jump? I can see where the piston hit valve but I got lucky and no sign of damage to piston visually. Valve was of course bent though.

Truck has 113,000 miles and has had Mobil 1 synthetic oil change every 4,000 miles. Truck has been pretty reliable in the last 6 years of ownership. Took the head off and it’s currently at machine shop getting all new valves, seals, and springs put on.

My question is what do you think caused this? Should I check the camshaft, timing chain,
replace oil pump, camshaft position sensor, actuator magnet, etc?? I’m a little strapped for cash so trying to make accurate repairs myself but don’t want to re-assemble just to have to break it down again. Any help or similar situation would be great!! Thank you all.

This is the first failure of a valve stem at that point I’ve ever heard of on one of these. Not that my experience is complete, but it’s a rare event. My guess is a metallurgical flaw in the valve stem.

When it dropped, it surely smacked the piston. I would clean the top of the piston up completely and make a thorough visual inspection at a minimum and consider a dye penetrant inspection for any cracks.

 

[Jimmyy]

Good reason to run a 6.2 on premium fuel

Ran across this video while sitting on a Boeing 737, flying home from a work trip for the first time in more than a year. Anyway, the guy does a teardown on a an auction-acquired 6.2 L92, and makes several comments about it that I did not know. Namely, that these engines apparently frequently...

www.tahoeyukonforum.com

There is a tread with interesting opinions on the 6.2. Plus a video on a tear down.

 

[wsteele]

Kind of troubling the Random/Multiple misfire code. If the problem was isolated to the one cylinder, I would have expected a P0303.

FWIW, P0300 doesn't automatically mean you have a random misfire. You can have consistent misfires in more than one cylinder and have it produce a P0300. Knowing which cylinders had the misfire might help a lot.

 

[swathdiver]

Hey all! New member here and I really appreciate all of the threads on various issues. Has helped me tremendously on previous repairs.

I have a 2007 Escalade AWD with the 6.2L. Recently while getting on it and accelerating on the freeway the engine straight up popped and had instant loss of power. Check engine light flashing and stabilitrak came on right away. I drove it another 1/2 mile barely to exit and parked it. Towed it home, scanned it and only had P0300 (random misfire), and instantly compression tested it. All cylinders were great and over 160 psi but cylinder 3 was dead 0 psi.

At this point, I figured a broken valve spring. Took off valve cover but instead I found broken intake valve on the stem right by the retainer clip! Couldn’t believe it. Maybe it was caused by valve float? Or did timing jump? I can see where the piston hit valve but I got lucky and no sign of damage to piston visually. Valve was of course bent though.

Truck has 113,000 miles and has had Mobil 1 synthetic oil change every 4,000 miles. Truck has been pretty reliable in the last 6 years of ownership. Took the head off and it’s currently at machine shop getting all new valves, seals, and springs put on.

My question is what do you think caused this? Should I check the camshaft, timing chain,
replace oil pump, camshaft position sensor, actuator magnet, etc?? I’m a little strapped for cash so trying to make accurate repairs myself but don’t want to re-assemble just to have to break it down again. Any help or similar situation would be great!! Thank you all.

Valve spring weak and stretched out? Anything wrong with the retainer? Just a fluke then maybe.

 

[Esko07]

This is the first failure of a valve stem at that point I’ve ever heard of on one of these. Not that my experience is complete, but it’s a rare event. My guess is a metallurgical flaw in the valve stem.

When it dropped, it surely smacked the piston. I would clean the top of the piston up completely and make a thorough visual inspection at a minimum and consider a dye penetrant inspection for any cracks.

I know, This seems extremely rare. I can see where the valve hit the piston but looks like it was bouncing on top of it. Cleaned the top of piston and no cracks and cylinder walls look legit. Think I got lucky somehow. Just got the head back from machine shop and putting it all together as we speak. Even took timing cover off, replaced oil pump and checked timing. All is good so far. I’ll keep everyone posted when I fire her up at the end of week.

 

[Esko07]

Valve spring weak and stretched out? Anything wrong with the retainer? Just a fluke then maybe.

Yeah could have been a weak spring for sure. That’s my thought as well as it happened when I was accelerating to get over into the carpool lane. Timing all checks out fine. Retainer was fine and still attached to spring. Just got the head back from machine shop and re-assembling as we speak. Will keep you posted on results. Crossing my fingers.

 

[Esko07]

Kind of troubling the Random/Multiple misfire code. If the problem was isolated to the one cylinder, I would have expected a P0303.

FWIW, P0300 doesn't automatically mean you have a random misfire. You can have consistent misfires in more than one cylinder and have it produce a P0300. Knowing which cylinders had the misfire might help a lot.

I thought of this as well but sometimes it takes time to kick a code for a specific cylinder. I shut her down pretty quick after the pop and reduced power. After dissembling and compression testing all cylinders, cylinder 3 was definite the culprit. Not saying others didn’t contribute but this is just my opinion from visual inspection putting it back together soon and will let you know results. I’m also replacing plugs, plug wires, oil pump, and camshaft position sensor since I’m this far into it.

 

[Esko07]

Good reason to run a 6.2 on premium fuel

Ran across this video while sitting on a Boeing 737, flying home from a work trip for the first time in more than a year. Anyway, the guy does a teardown on a an auction-acquired 6.2 L92, and makes several comments about it that I did not know. Namely, that these engines apparently frequently...

www.tahoeyukonforum.com

There is a tread with interesting opinions on the 6.2. Plus a video on a tear down.

Just watched this! Oh wow, not good news at all. Praying mine fires right back up.

 

[Jimmyy]

Just watched this! Oh wow, not good news at all. Praying mine fires right back up.

I got my fingers crossed for you. Best of luck.

 

[Esko07]

So just got it all back together and it fired right back up! But there are some issues. Now it is throwing code P0010 for the camshaft position sensor even though I just replaced it and the magnetic actuator. Do I need to have it tuned now? I thought that was only for the crankshaft position sensor. Really appreciate all of the help so far and the positive vibes!

 

[wsteele]

So just got it all back together and it fired right back up! But there are some issues. Now it is throwing code P0010 for the camshaft position sensor even though I just replaced it and the magnetic actuator. Do I need to have it tuned now? I thought that was only for the crankshaft position sensor. Really appreciate all of the help so far and the positive vibes!

I don't think there is a camshaft sensor relearn procedure. Maybe a wire got nicked/pinched?

 

[Snowbound]

Should just be able to R&R cam sensor without doing any type of relearn or correlation calibration. Maybe just try clearing code and see if it comes back. Check connector pins at a minimum.

 

[Esko07]

Should just be able to R&R cam sensor without doing any type of relearn or correlation calibration. Maybe just try clearing code and see if it comes back. Check connector pins at a minimum.

Will check all of these first thing tmw and report back. Thank you!

 

[Esko07]

I don't think there is a camshaft sensor relearn procedure. Maybe a wire got nicked/pinched?

Okay thanks! I’ll make sure to check wiring. Hopefully it’s a simple fix.

 

[wsteele]

Okay thanks! I’ll make sure to check wiring. Hopefully it’s a simple fix.

I think @Snowbound had a good idea to try clearing that P0010 and see if it comes back. When first firing things up after being all apart, no oil in places that normally have oil, etc., you may have thrown a code that you might not see again. VVT uses oil pressure.

 

[Esko07]

I think @Snowbound had a good idea to try clearing that P0010 and see if it comes back. When first firing things up after being all apart, no oil in places that normally have oil, etc., you may have thrown a code that you might not see again. VVT uses oil pressure.

Cleared the code, drove around for about 15 miles but it returned on next startup. Disconnected the actuator from the wiring harness and cleaned it up but didn’t see anything broken. The wiring is stiff to the touch as from the heat of the engine. Will need multimeter to test continuity next. Engine runs better than it ever has before though but I have the stabilitrack and service traction control dang it! Hope it’s only related to code P0030.

 

[Esko07]

Cleared the code, drove around for about 15 miles but it returned on next startup. Disconnected the actuator from the wiring harness and cleaned it up but didn’t see anything broken. The wiring is stiff to the touch as from the heat of the engine. Will need multimeter to test continuity next. Engine runs better than it ever has before though but I have the stabilitrack and service traction control dang it! Hope it’s only related to code P0030.

Whoops, I mean code P0010 for the camshaft sensor actuator wiring open bank 1.

 

[wsteele]

One thing I noticed in the shop manual was the Actuator Solenoid is a one use item. I believe that is related to the torque to yield status and probably isn’t the problem if you didn’t replace it, just thought I would throw it out. All the stuff I have seen about fixing the P0010 usually involves replacing that bolt. Again, totally anecdotal impressions.