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Blown Head Gasket or Dropped Valve? Cylinder Head Rebuild Advice

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Blown Head Gasket or Dropped Valve? Cylinder Head Rebuild Advice

  #1  
Old 01-05-2014, 12:51 PM
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Default Blown Head Gasket or Dropped Valve? Cylinder Head Rebuild Advice

So, last night when getting on it a little bit merging onto the highway, the car started to spit and sputter a lot and hesitating a lot. The battery light came on and the check engine light started flashing and the car shut off. When trying to start it up it was pouring white smoke, stumping and ticking. The check engine light said multiple misfire (cylinder 3), so I looked at the plug and it has some fluid on it and I changed the coil pack and it took the check engine light go away but it's still thumping.

What do you think it is? If I have to rebuild the head whats some good advice to make it nice and strong with a little bit more power?

Thanks
 
  #2  
Old 01-05-2014, 02:32 PM
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I don't think its a blown head gasket. Your probably leaking coolant, causing the white smoke.

Being that its a four banger, rebuilding the entire head would run you a few thousand, assuming you rebuild it to withstand higher boost.

There are new turbines on the market these days. They are called "dual boost turbines"

Some of the advantages are a dual sided axial flow compressor, horizontal inlets/outlets, less inertia and lower operating temperatures.
 
  #3  
Old 01-05-2014, 03:01 PM
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Kamil, I don't know what you're talking about. There is no way that rebuilding a head should cost a couple grand unless you're replacing every component with aftermarket products. Nor does a head need to be rebuilt to withstand "higher boost." And why you're bringing up turbines is beyond me, that's not even being discussed.

A head can "fail" due to excessive RPMs. What happens is that the stock springs are not able to keep up with the engine and you end up floating the valves causing contact with the pistons. Aftermarket springs will be able to return the valve to the closed position fast enough to allow for speeds beyond 7k RPM.

I have no experience rebuilding heads, so take what I say with a grain of salt. However, the stock exhaust valves are sodium filled for thermal reasons. Over time that sodium breaks down leaving a hollow shaft that is more easily bent. Usually the exhaust valves are replaced with a solid stainless steel variant.
 

Last edited by BaseDrifter; 01-05-2014 at 03:04 PM.
  #4  
Old 01-05-2014, 03:08 PM
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Lately if I have been going about 50 on the highway and try to cram it while it 4 gear, the boost will shoot up but the car will just buck around, hesitate and back fire a lot. This time it cause a even bigger problem
 
  #5  
Old 01-05-2014, 03:42 PM
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Have you checked the timing belt?

As for sodium-filled valves, the only two ways for the sodium to escape are if the valve face is drilled through, which is the procedure to dispose of old valves prior to dropping them into a bucket of water and watching the sodium 'explode', or if there is a catastrophic failure that physically breaks the valve.
 
  #6  
Old 01-05-2014, 03:47 PM
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Originally Posted by BaseDrifter View Post
Kamil, I don't know what you're talking about. There is no way that rebuilding a head should cost a couple grand unless you're replacing every component with aftermarket products. Nor does a head need to be rebuilt to withstand "higher boost." And why you're bringing up turbines is beyond me, that's not even being discussed.

A head can "fail" due to excessive RPMs. What happens is that the stock springs are not able to keep up with the engine and you end up floating the valves causing contact with the pistons. Aftermarket springs will be able to return the valve to the closed position fast enough to allow for speeds beyond 7k RPM.

I have no experience rebuilding heads, so take what I say with a grain of salt. However, the stock exhaust valves are sodium filled for thermal reasons. Over time that sodium breaks down leaving a hollow shaft that is more easily bent. Usually the exhaust valves are replaced with a solid stainless steel variant.
He asked what he needed to do to get more power. If you are going to rebuild the head, you might as well install a bigger turbo.
 
  #7  
Old 01-05-2014, 03:52 PM
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If your valve dropped into the combustion chamber, your piston would look like Mount Rushmore.

The idea of the valve springs not being able to close the valve in time is interesting.
 
  #8  
Old 01-05-2014, 04:11 PM
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HBAudi, it is not a matter of the sodium finding a path to escape from the valve. The sodium changes form over hundreds of thousands of miles of use and heat cycles.

The other problem with the stock exhaust valves is that in the unfortunate case of a timing belt failure, they have a tendency to snap instead of bend and go on a rampage of destruction in the combustion chamber.

OP, have you scanned for codes since you replaced the coil pack? It's possible the car is still misfiring.
 
  #9  
Old 01-05-2014, 05:24 PM
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I have changed the coil pack and it doesn't show a misfire code anymore. But, I took the plug out the cylinder 3 (the one that was showing the misfire and when I bumped it once some liquid came out
Head gasket?
 
  #10  
Old 01-05-2014, 05:33 PM
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Head gaskets are not a common failure point on the 1.8T.

What do you mean bumped? You took the plug out and cranked it? Did you pull the fuel pump fuse or disconnect the injector plugs first?

What kind of fluid came out? Was there fluid in the cylinder before you cranked it?

Are there any other codes stored? Have you done a compression test?
 

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