Possible Valve Issue?

[xtmsports]

Hi Guys,

 

i have a 2002 2500HD with the 8.1L engine.

 

On the passenger side of the engine, there is a squeaking noise coming from inside the engine block close to spark plug 2 or 3. I am assuming that the valves are under that cover.

 

When the truck first starts up, there is a squeak for about 5 minutes of giving the truck gas. At idle, you dont hear the squeak. Only if you give it gas and then let off the pedal do you hear the squeak.

 

Spark plug 2 had some coolant leak onto it from the coolant sensor right above it. I have tightened the sensor and changed the spark plug. But it still makes the squeak. Could the spark plug wire be bad to cause this squeak?

 

If it is the valves, are they expensive to get fixed?

 

 

Thanks.

[10.90 hot rod]

I have heard exhaust leaks make a squeeking sound in the past. Most exhaust noises make puff or pop noise. Get someone to put a rag over the exhaust tail pipe while it is running and see if the noise changes . I have the same truck ( '03 8.1 allison ) and I had to remove the manifold and have it ground true due warpage which casuesd a mild leak. If it persist, go to GM and buy a can of Lubricity. I know it sounds like BS but GM makes this stuff and when I was a GM tech we would add it to engines that had valve train squeeks and it would get rid of the noise. NO joke.

[xtmsports]

I have heard exhaust leaks make a squeeking sound in the past. Most exhaust noises make puff or pop noise. Get someone to put a rag over the exhaust tail pipe while it is running and see if the noise changes . I have the same truck ( '03 8.1 allison ) and I had to remove the manifold and have it ground true due warpage which casuesd a mild leak. If it persist, go to GM and buy a can of Lubricity. I know it sounds like BS but GM makes this stuff and when I was a GM tech we would add it to engines that had valve train squeeks and it would get rid of the noise. NO joke.

 

 

Thanks for the information. I am going to replace the exhaust manifold gasket. Besides being an annoying sound, would it cause engine damage if not replaced?

 

I am assuming the gasket replacement is pretty easy?

[markw8]

I just had all fasteners and gaskets replaced on my 6.0. Don't assume it will be easy. One sibe of mine was ok the other was a bear to do. Mark.

[10.90 hot rod]

Unfortunately no , it will not be a matter of just undoing the manifold and sliding in a new gasket. The problem is that the manifold is going to be warped. Many big blocks suffered from this. Have you ever noted that many older Motorhomes with 454s have a tick to them ? In the case of those, the motor is worked so hard that the manifolds pretty much glow under hard pulls and it is the constant heating and cooling and lack of controlled contraction time that warps them . It then stresses the fasteners and causes the gasket to fail due to lack of retention. I've been through this on my own MH and found the 2500HD 8.1 did it too. The difference I found however, is that the material the 8.1 manifolds are made from is significantly harder. They must be resurfaced on a surface grinder or large belt sander, a traditional broch surfacer will not cut it. Just sliding a gasket in may hold for a while , but the noise will return. Replace the fasteners and run a tap in the bolt holes also when you do this job. Good Luck!