Intake valve spring broken - how lucky am I?

[gMcizzLe]

Car has been flawless for 5+ years...then an intake valve spring on cylinder #8 broke just after warranty expiration

Reading similar threads, it seems I was super lucky, as there appeared to be no damage other than the spring -- they did a compression test after replacing it and the cylinder was at 155psi.

This happened after downshifting a couple times coming off from the highway. My CEL starting flashing, service stabilitrack came on, car went into limp mode shaking bad, felt like it was going to stall, and I could smell gas. I limped it home 2-3 miles then got it towed to the dealer.

The odd thing is that my code reader said P0300 (multiple cylinder misfires), so I figured it was a bad sensor or something. However, the dealer tech said that both #5 and #8 were misfiring, but #5 held compression well (#8 had no compression). After replacing the #8 spring, everything was good.

Can a bad spring in one cylinder cause another to misfire somehow?

PSA: Use brakes instead of downshifting. Don't be an idiot like me that tried to save some pad a brake job is way cheaper!

[InFiD3ViL]

Originally Posted by gMcizzLe

PSA: Use brakes instead of downshifting. Don't be an idiot like me that tried to save some pad a brake job is way cheaper!

Meh, spring was likely already weak. Downshifting itself didn't cause it. Now it's a different story if you pulled a bonehead move and money shifted it or ran it into redline on the downshift. But only you know the answer to that. If you did you can tell us lol. We don't judge too harshly here!

Within reason, downshifting should be fine for some engine braking.

[gMcizzLe]

Originally Posted by InFiD3ViL

Meh, spring was likely already weak. Downshifting itself didn't cause it. Now it's a different story if you pulled a bonehead move and money shifted it or ran it into redline on the downshift. But only you know the answer to that. If you did you can tell us lol. We don't judge too harshly here!

Within reason, downshifting should be fine for some engine braking.

Nope just a normal 3-4k RPM 5->4->3. Yeah I figure it was probably weak before it broke, but hard to tell

The tech suggested that I must miss shifts, downshift hard, or just beat the crap out of my car. Then I told him I just replaced my factory tires after 39k miles

[Spec]

I was cruising on I-15 one morning... 77mph, when all of a sudden the car started shaking and started sounding really bad... something definitely broke. Check engine light came on...


I put it in neutral and coasted towards the nearest exit, parked around the corner in a safe place and shut it down.


When it got lighter out, I called for a flat bed truck and my car ended up at Allen GMC out of Laguna Niguel.


The service dept said on quick that somethings wrong with Cylinder 3. Had a P0300 code.


Further inspection and the verdict was that one of my rocker failed, killing the spring too. Mine happened on Cylinder 3.


Allen GMC took good care of me getting my car back and fixed in 24hrs. I felt lucky too because there was no other damage. Car felt great and I left there happy.


This at 83k miles... I'm now at 167k+ and still going strong.


Yes, this happened to me too... but the bright side is that apparently your car too will be okay.


How many miles on yours, bout 40k when this happened?


To add, I too was out of warranty... end of the day 550 out the door...

[gMcizzLe]

Originally Posted by Spec

I was cruising on I-15 one morning... 77mph, when all of a sudden the car started shaking and started sounding really bad... something definitely broke. Check engine light came on...


I put it in neutral and coasted towards the nearest exit, parked around the corner in a safe place and shut it down.


When it got lighter out, I called for a flat bed truck and my car ended up at Allen GMC out of Laguna Niguel.


The service dept said on quick that somethings wrong with Cylinder 3. Had a P0300 code.


Further inspection and the verdict was that one of my rocker failed, killing the spring too. Mine happened on Cylinder 3.


Allen GMC took good care of me getting my car back and fixed in 24hrs. I felt lucky too because there was no other damage. Car felt great and I left there happy.


This at 83k miles... I'm now at 167k+ and still going strong.


Yes, this happened to me too... but the bright side is that apparently your car too will be okay.


How many miles on yours, bout 40k when this happened?


To add, I too was out of warranty... end of the day 550 out the door...

Yeah just under 40k here. Only $550? Wow, good deal. I paid about $700.

[xc_SS/RS]

I had this happen when I first got my car. #8 intake spring broke. They replaced the spring and it fired right up and drove/idled perfectly. Still going strong at 117k lol this happened in 2014

[obe1]

My #6 intake valve spring broke Monday; was at ~1,200 rpm under light load in a parking lot. 163,000 miles so can't complain.

[detamble13]

My Camaro is currently at the dealership having all the valve springs replaced.
Yesterday as I was driving into work I experienced the loss of power and some noise. I was lucky it happened as I was pulling into work so I parked it and had it towed to the dealership. This is the second valve spring that has broken on me. The first went in 2015 and was replaced under warranty. First to go was cylinder 2 intake, second was cylinder 4 intake.
I'm sure I got a bad batch of valve springs with my LS3 so I decided to replace them all. This car is my daily driver and I'm mostly to and from work and around town. Yes I get on it from time to time but I don't beat on it. I'm only 58000 km's (36250 mi.) in and wish I would have made more of a case to replace them all under warranty.
Am I lucky there isn't a bent valve or damaged piston?

[Greenhornet2]

You could always put a lower lift cam in your car and they would stop breaking =)

[wasthatacop?]

Originally Posted by Greenhornet2

You could always put a lower lift cam in your car and they would stop breaking =)

Or replace the springs yourself. The factory cam is not a high lift cam. Springs and pushrods in the stock engine are weak links.

[wasthatacop?]

Originally Posted by gMcizzLe

Yeah just under 40k here. Only $550? Wow, good deal. I paid about $700.

That's crazy, valve springs with install go for $500-$700!? The springs are about $100 without install.

[flht99b]

If you are driving HP cars at least part of the time as they were intended to be driven, 30 to 40k miles valve spring replacement is cheap insurance on a basically stock or header/intake modded LS3 or L99. Sooner if car is raced at drag strip, autocross or road course. Just part of the regular maintenance of a high performance car.

[InFiD3ViL]

Originally Posted by wasthatacop?

That's crazy, valve springs with install go for $500-$700!? The springs are about $100 without install.

I agree. Labor costs are nuts. But it's not something I would recommend to someone that isn't capable or sure of their wrenching skills, just to save $500-600. So it's worth it to them I suppose.

I assume when the dealer does a spring change that they don't replace seals, retainers, or locators either - unless requested and added to the total cost. Kinda a 'while your in there' thing.

[wasthatacop?]

Originally Posted by InFiD3ViL

I agree. Labor costs are nuts. But it's not something I would recommend to someone that isn't capable or sure of their wrenching skills, just to save $500-600. So it's worth it to them I suppose.

I assume when the dealer does a spring change that they don't replace seals, retainers, or locators either - unless requested and added to the total cost. Kinda a 'while your in there' thing.

Yea, and even if you requested for the dealer to replace seats, retainers, etc, you won't really know if they did.