Broken valve spring @ 39k miles - what to do?

[boonkauc]

A few days ago while driving to work the engine began to shake and the CEL started flashing and loss of power, luckily I was about 1000 ft from work and was able to coast there, but had to have the car towed to the dealer.

The dealer said misfire on cylinder #2, they checked compression and it was at 0 psi. Today I spoke with them and while they originally thought the engine was toasted, once the tech got in there he's now saying it's a broken valve spring.

This is beyond my expertise so I'm wondering how this actually happened, everything I've read would point to either a bad part (unlikely) or overrev (I drive like an old man most of the time). I'd be more concerned about the effects this may have - i.e. did this broken spring cause any other damage, and also what the root cause of this issue is.

Is there anything I should ask the dealership to ensure nothing gets overlooked on the repair? I'm at 3 years / 39k miles so I've still got some time on warranty, but I'd hate to have the underlying cause not fixed and have another issue down the road.

Obviously it can be hard to diagnose without seeing it, but I'm just wondering if anything comes to mind for some of the more knowledgeable guys here. Any help is appreciated!

Thanks

[JeriQo]

its under warranty ... is the dealer refusing to service it?

[pierreb]

It depends on what the dealer proposes for a fix. Personally I'd ask for new cams and valves all around. Basically a new cyl head plus new cams.

I'd also pay to have the chain tensioner updated.

[lettuce]

Damn, that's rough. Broken valve spring means two things.

One, your valve was just floating around in your guide, which means with every revolution of your engine it was potentially slapping against your piston. Could have broken apart, in which case it may have exited in pieces out your exhaust valve and into your turbo's turbine. Even if it didn't, you'll be needing a piston replacement at the very least in addition to the valvetrain fix.

Two, whatever piece of your broken spring, including your valve keepers and your retainer were/are loose in your engine and if you're extremely lucky made their way into the oil pan without causing any serious damage along the way. The retainer is too big to fit through any of the oil valleys in the head so that's probably still sitting in there somewhere, but the other parts are probably loose in your engine. That could have caused serious damage if you didn't shut the car off immediately.

Either way you're under warranty, so I would press for a complete engine and turbo replacement.

[Allowencer]

Damn, that's rough. Broken valve spring means two things.

One, your valve was just floating around in your guide, which means with every revolution of your engine it was potentially slapping against your piston. Could have broken apart, in which case it may have exited in pieces out your exhaust valve and into your turbo's turbine. Even if it didn't, you'll be needing a piston replacement at the very least in addition to the valvetrain fix.

Two, whatever piece of your broken spring, including your valve keepers and your retainer were/are loose in your engine and if you're extremely lucky made their way into the oil pan without causing any serious damage along the way. The retainer is too big to fit through any of the oil valleys in the head so that's probably still sitting in there somewhere, but the other parts are probably loose in your engine. That could have caused serious damage if you didn't shut the car off immediately.

Either way you're under warranty, so I would press for a complete engine and turbo replacement.

So, its possible this can happen under 'normal' conditions, but it's highly unlikely.

First question: is it on the exhaust side or intake side?

I'll add to what lettuce said as he's pretty spot on; however, having seen broken valve springs in the past on engines, there's a good chance everything is still, somewhat, mated on the valvetrain. It all depends on how the valvespring broke. To add, there's even a good chance the valve never made contact with the piston. Think about it, when the piston goes on its down stroke, the 'suction' will pull the valve down; hence why you get a misfire because there's no compression. On the pistons up stroke, the 'rush' of air volume will push the valve back up and into the head. I would, for sure, ask the dealer to actually 'visually' look at the motor - you will be able to see if the piston is damaged for yourself. They must allow you to 'see' the motor if you ask.

Worst case, the valve literally dropped into the cylinder, which means the keepers didn't hold the retainer to the valve stem. This would make a WHOLE TON of noise, wreck the cylinder walls, the piston's crown and the combustion chamber. That's a new motor right there for sure; however, based on what you explained, it doesn't sound like this is the case. Which would mean the valvetrain is still mated to a certain degree and parts didn't go anywhere they could find their way through the motor.

Back to my question, depending on what type of valve spring (intake/exhaust), if exhaust, it's possible the exhaust cam lobe pairs jumped which could mean a bad cam.

Regardless, I'd ensure whatever side (intake/exhaust) failed, that cam is inspected with a fine tooth comb.

If new cams are needed, I'd push for a new cylinder head as well as the cam journals are within the head (the head itself and valve cover); they cannot be reconditioned. It's $1500 for a replacement head (I don't think it comes with any valvetrain).

[boonkauc]

So, its possible this can happen under 'normal' conditions, but it's highly unlikely.

First question: is it on the exhaust side or intake side?

I'll add to what lettuce said as he's pretty spot on; however, having seen broken valve springs in the past on engines, there's a good chance everything is still, somewhat, mated on the valvetrain. It all depends on how the valvespring broke. To add, there's even a good chance the valve never made contact with the piston. Think about it, when the piston goes on its down stroke, the 'suction' will pull the valve down; hence why you get a misfire because there's no compression. On the pistons up stroke, the 'rush' of air volume will push the valve back up and into the head. I would, for sure, ask the dealer to actually 'visually' look at the motor - you will be able to see if the piston is damaged for yourself. They must allow you to 'see' the motor if you ask.

Worst case, the valve literally dropped into the cylinder, which means the keepers didn't hold the retainer to the valve stem. This would make a WHOLE TON of noise, wreck the cylinder walls, the piston's crown and the combustion chamber. That's a new motor right there for sure; however, based on what you explained, it doesn't sound like this is the case. Which would mean the valvetrain is still mated to a certain degree and parts didn't go anywhere they could find their way through the motor.

Back to my question, depending on what type of valve spring (intake/exhaust), if exhaust, it's possible the exhaust cam lobe pairs jumped which could mean a bad cam.

Regardless, I'd ensure whatever side (intake/exhaust) failed, that cam is inspected with a fine tooth comb.

If new cams are needed, I'd push for a new cylinder head as well as the cam journals are within the head (the head itself and valve cover); they cannot be reconditioned. It's $1500 for a replacement head (I don't think it comes with any valvetrain).

Thanks a lot, that really helps give me some discussion points in talking to the dealer today. You've highlighted what my main concern is - that there are no lingering effects due to this breakage. I'll ask today if it was on the engine side or exhaust side.

As for the valve dropping in the cylinder, I don't think it happened as I didn't hear anything crazy from the engine other than it had a misfire so it shook a lot and I had immediate power loss.

Thanks

[Allowencer]

Hey bud, curious if you have an update on your car?