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2015 C7 Automatic 36k miles.
Driving at 30 mph and engine began to run rough, pulled over, and it died. Pulled drivers side valve cover and found the #3 cylinder has a broken valve spring. Valve is still retained. My borescope isn't very good but did not see any piston damage. Need some guidance on the next steps.
1. Should I replace all valve springs?
2. Figure I will use this tool or the Kent Moore J38606 tool and compressed air to hold the valves in place.
3. Where should I get the valve spring(s) from?
4. Should I deactivate AFM with an AFM Disabler? If so, which one do you suggest?
5. Let me know if I have overlooked something.
Change all the springs. I had brkn valve spring at 36k on my '16 Z51 and only had the brkn spring replaced.
Broke another valve spring at 61700 mile while cruising on highway at 55 mph in 6th gear and this time the valve dropped into the cylinder. New GM LT1 crate engine which GM paid 40% even though car was technically out of warranty.
I'll have the valve springs on the new engine changed , probably every 3 years or 36000 miles. lesson learned
Last edited by blueray16; Oct 28, 2020 at 08:13 PM.
Spoke to the local dealer today about OEM Springs. They said, the springs are on back order. Wonder Why! $3.00 valve springs made in China I'm betting. Argh
Anyway, BTR fixed me up.
Spoke to the local dealer today about OEM Springs. They said, the springs are on back order. Wonder Why! $3.00 valve springs made in China I'm betting. Argh
Anyway, BTR fixed me up.
Check your cam for scoring. Very likely with a broken spring and the car running rough. My 16 Z51 had this issue at 7k miles. M7, so it was never in v4 mode. I know, it was mine since 5 miles on the clock. That v4/v8 switch fear is a myth. The DOD lifters in general are garbage. As soon as my Z06 is out of warranty, the whole DOD/VLOM, lifters, etc going in the trash. Being replaced with quality, solid parts.
Just had one break on me almost a month ago. 2014 C7 z51 Auto with 35k miles on it and i usually drive it in manual to avoid the V8/V4 switch. I replaced the older yellow valve springs with the newer GM OEM blue springs P/N- 12691120. I also had to replace the pushrod where the spring broke because it got bent. Make sure to check for that as well. I would definitely recommend changing all of the springs. Have put over 1k miles on the new springs since the change car runs extremely smooth.
Could've done the work myself but figured i got lucky enough for the valve not dropping didn't want to risk messing something else up trying to install the springs. Parts cost me around $200 and $400 labor for valve springs, spark plugs, and plug wires changed. $600 is alot better than a new engine especially when you are out of warranty!
How do I know i have a broken valve spring? My mechanic says i may have one. The engine misfires occasionally. Yet I have no service engine soon light come on. I use to think it was the mild camshaft in the LT1 making for a rough idle. Now I am not sure. I don't race the engine. I don't track the car. .My c7 is a 2016 z51 A8 with 20k miles.
Should I bring it to the dealer to havee ir checked for warranty repair, if needed to?
How do I know i have a broken valve spring? My mechanic says i may have one. The engine misfires occasionally. Yet I have no service engine soon light come on. I use to think it was the mild camshaft in the LT1 making for a rough idle. Now I am not sure. I don't race the engine. I don't track the car. .My c7 is a 2016 z51 A8 with 20k miles.
Should I bring it to the dealer to havee ir checked for warranty repair, if needed to?
Please advise.
Thx
pop the valve covers and take a look. Should be able to visibly see if there’s a broken spring. But if you car is still under warranty.. I’d have it dropped off ASAP for warranty for sure.
How do I know i have a broken valve spring? My mechanic says i may have one. The engine misfires occasionally. Yet I have no service engine soon light come on. I use to think it was the mild camshaft in the LT1 making for a rough idle. Now I am not sure. I don't race the engine. I don't track the car. .My c7 is a 2016 z51 A8 with 20k miles.
Should I bring it to the dealer to havee ir checked for warranty repair, if needed to?
Please advise.
Thx
Aside from misfires occasionally, some odd noises may come and go at idle or under load. Depending on the in-service date, you likely still have the powertrain warranty, which will cover the lifters. Take it to a competent dealer in your area see what they say.
pop the valve covers and take a look. Should be able to visibly see if there’s a broken spring. But if you car is still under warranty.. I’d have it dropped off ASAP for warranty for sure.
I will have my local dealer investigate while it is under warranty next time I bring it in for an oil change. I am not getting any service engine soon lights.
Aside from misfires occasionally, some odd noises may come and go at idle or under load. Depending on the in-service date, you likely still have the powertrain warranty, which will cover the lifters. Take it to a competent dealer in your area see what they say.
I will have the dealer look at it at the next oil change. I am not getting any service engine soon lights. Thanks.
I will have the dealer look at it at the next oil change. I am not getting any service engine soon lights. Thanks.
Only issue with waiting is if your mechanic is right, then you can actually make it worse by waiting. Possible metal debris traveling, scoring, etc... I'd say, for peace of mind, do it sooner than later
Broken Valve Spring
