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Discussion Starter #1 (Edited)
I have a 2013 1.4 turbo cruze with 172,000 miles on it...all highway miles......lost power going up a hill....service stabilitrak and traction control came on display and check engine light code of p0303 misfire cylinder #3 was read out later after limping it back home at reduced power skipping and jerking ....Checked cylinder #3 plug and it looked fouled all others were clean...replaced all with new plugs....still didn't help...still miss-fire cylinder #3.....checked compression in all cylinders...#1,2,4 were from 185-200 psi ...cylinder # 3 was >> 0 psi<<??......poured a little oil in #3 and checked again...still 0 psi....is this a burnt valve or cracked piston/ring lands?? any advise on diagnosing this further?
 

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You'll need to do a cylinder leak down test.

Have a compressor running air in to the cylinder. Listen for air coming from the valve cover, that's the pistons. Coming from the air filter. Intake valve. Coming from the exhaust. Exhaust valve.

The spark plug is going to be wet because there's no compression to make it fire. You need 80 pounds compression bare minimum to make it happen.
 

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Discussion Starter #3
*UPDATE* on the 1.4 with no compression on #3.....did a leakdown test and #3 cyl on compression stroke....air is coming out exhaust no other air is coming out oil fill or intake......suspect burnt exhaust valve?
 

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If you comfirmed piston at top dead center compresson/power stroke. With both valves closed.

Yes. Exhaust valve.

You should be able to hear a burnt valve with engine running as the exhaust will make puffing sounds.
 

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Discussion Starter #5
I did confirm the exhaust is puffing....also looked down cylinder #3 with a borescope....lots of carbon on top center of piston...but i see no cracks or missing piston pieces ....pulling head off soon...should reveal my suspicion of burnt exhaust valve.
 

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With that many miles. It's generally a good idea to rebuild the engine.

Generally.

Rebuilding the head with new valves will bring compression back up. Having good compression on old piston rings might cause the rings to break down.

Technically speaking.

You might get by with reconditioning the head and replacement of the valves for just #3. MIGHT.

You might get it all done and still have problems with the pistons.

Might just be cheaper and easier to find a used motor instead. Less gamble over trying to fix the cylinder problem.
 

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I did confirm the exhaust is puffing....also looked down cylinder #3 with a borescope....lots of carbon on top center of piston...but i see no cracks or missing piston pieces ....pulling head off soon...should reveal my suspicion of burnt exhaust valve.
Hey Biggen, what was the outcome of this ? did you ever pull the head ? What did you end up doing ?
 

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I just rebuilt my 2012 that had a #3 exhaust valve burned off.

No issues with my rings or pistons. $400 head rebuilt, new springs, guides, seals, and valves.

I cleaned all the carbon of the pistons. I also pulled the oil pan and completely cleaned lower end also.

No misfires and excellent compression. I put a new timing set on also. I only had 98,000 but I would be optimistic that yours would have good compression with a good head. The rings and pistons are good and reliable for a stock set up.
 

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With that many miles. It's generally a good idea to rebuild the engine.

Generally.

Rebuilding the head with new valves will bring compression back up. Having good compression on old piston rings might cause the rings to break down.

Technically speaking.

You might get by with reconditioning the head and replacement of the valves for just #3. MIGHT.

You might get it all done and still have problems with the pistons.

Might just be cheaper and easier to find a used motor instead. Less gamble over trying to fix the cylinder problem.
Logically bringing compression back to where it was before loss won't cause anymore wear to rings than what was occurring with normal compression before valve burned off.
 

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Logically bringing compression back to where it was before loss won't cause anymore wear to rings than what was occurring with normal compression before valve burned off.
Not logical.

Sudden loss of compression. Something has happened and is creating damage.

Normal loss of compression. As the motor wears with age. Replace new head on worn piston rings. Is hard on the rings.

It's a no win scenario.

A 10k mile motor could handle it.

A 100k mile motor. Maybe. If the rings and cylinders are still in pristine condition. In all cylinders. Odds are. They're not.

OP has 172k miles.

A motor with 1 or more cylinders with low or lower compression. Isn't an ideal candidate for a new head. And it's not just the rings at stake. Cylinder walls, piston rods, bearings, crankshaft.

A bad cylinder is a motor out of balance.

An 8 cylinder motor won't get hammered as much as a 4 cylinder motor.
 

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Not logical.

Sudden loss of compression. Something has happened and is creating damage.

Normal loss of compression. As the motor wears with age. Replace new head on worn piston rings. Is hard on the rings.

It's a no win scenario.

A 10k mile motor could handle it.

A 100k mile motor. Maybe. If the rings and cylinders are still in pristine condition. In all cylinders. Odds are. They're not.

OP has 172k miles.

A motor with 1 or more cylinders with low or lower compression. Isn't an ideal candidate for a new head. And it's not just the rings at stake. Cylinder walls, piston rods, bearings, crankshaft.

A bad cylinder is a motor out of balance.

An 8 cylinder motor won't get hammered as much as a 4 cylinder motor.
The exact same happened on mine. The valve burned off from a worn spring and carbon build up. I've repaired a few with no issues to lower half just the head issues.

Though he lost power going up hill, when we look at the history of this particular engine composition and issues it has, it was most likely blowing past the side of that valve for a while and finally burned the edge off.

The lower half of these engines are reliable. Typically no issues with pistons and rings unless heavily modified and factory pistons and rings were left in.

From my experience on these I'd be optimistic on rebuilding or replacing the head if the head is not able to be.

That's just my honest opinion from experience. It's ultimately the OP's choice.

But when you logically and technically think about it it would have the same amount of compression as before the valve burned off. There's no way you're able to add Extra compression without heavily modifying. If you're just rebuild/replacing it, it would be identical to as it was before.
 

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@Miguelcon74
If you have not installed the PCV fix kit sold by another member here yet on this car, do it now!

The sheer amount of oil that gets pushed through the intake plumbing when the check valve in the intake manifold isn't functioning gets sucked into the motor, makes a mess of everything, and creates hot spots on the valves that can burn when put under a sustained load.

My old Volvo S70 burnt 2 going up a hill @ 250k, but the valve seals had been leaking on it for some time.

@OP with high mileage on the original motor, your best bet might be finding a lower mileage one in the junkyard.
 

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@Miguelcon74
If you have not installed the PCV fix kit sold by another member here yet on this car, do it now!

The sheer amount of oil that gets pushed through the intake plumbing when the check valve in the intake manifold isn't functioning gets sucked into the motor, makes a mess of everything, and creates hot spots on the valves that can burn when put under a sustained load.

My old Volvo S70 burnt 2 going up a hill @ 250k, but the valve seals had been leaking on it for some time.

@OP with high mileage on the original motor, your best bet might be finding a lower mileage one in the junkyard.
I have, I made my own for around $45
 
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