Uneven turbo whistle

[AMink]

I don't know if this is a problem or not. Hadn't really paid too much attention but I noticed that under full throttle, my turbo whistle is not steady. It is linear up to a point then it oscillates. Is that normal? If not, what could be the cause? I just tightened all the clamps on the hoses to and from the intercooler.

I do have a slight exhaust leak between the exhaust manifold (BD two piece) and the turbo. I've had two or three gaskets on that without luck. The truck runs fine and doesn't surge. There are not other modifications other than a Cool Blue intake hose.

 

[seafish]

Could easily be the exhaust leak getting worse and effecting turbo rpm.

 

[AMink]

Could easily be the exhaust leak getting worse and effecting turbo rpm.

That's kind of what I was thinking. I just can't get a good seal between the manifold and turbo. I bought the gaskets from Cummins but they just don't seem to do it. I'm hoping to avoid having to get the parts refinished. Can two gaskets be used together?

 

[seafish]

That's kind of what I was thinking. I just can't get a good seal between the manifold and turbo. I bought the gaskets from Cummins but they just don't seem to do it. I'm hoping to avoid having to get the parts refinished. Can two gaskets be used together?

I have heard about people doing that, but really it is an open question as to whether they will seal…mostly depends on how much "unevenness" there is the two flanges and if the double gasket can make up for that amount. I would think that by the time you have the turbo removed to put the new gasket in place, it might just be better to have both flags resurfaced…you could also have them ported and gasket matched at the same time if you were particularly discerning. Of course, that will be more work and downtime, so I can see why you are trying to avoid it, but IMHO it is the better way to go.

 

[Bob4x4]

The multi layer steel gaskets are the ones that work the single layer not so good

 

[AMink]

The multi layer steel gaskets are the ones that work the single layer not so good

Where are you finding the multi layer gasket? I can find the whole exhaust manifold set but not just the turbo gasket.

 

[Bob4x4]

Where are you finding the multi layer gasket? I can find the whole exhaust manifold set but not just the turbo gasket.

Sorry my mistake. I thought we were talking mani to head not turbo. The turbo to Mani should have a rolled bead. I haven't ever had an issue with dealing that joint. I have done hundreds of manifolds and turbos. On the 3rd gens I generally mount the turbo to the manifold and then the assy to the head especially with a larger than stock turbo

 

[AMink]

Had leaking manifold gaskets a few years back so removed the mani to replace. It was warped and wouldn't fit back on, which I guess is fairly common. Put on the BD two-piece. New turbo gasket didn't seal. Got another. It was better and leaked a little but I think it's getting worse. Just put on a new gasket today but managed to bounce one of the nuts somewhere. I'll look for it in the morning. What a PIA.

 

[p-Bar]

How about using some high temp silicone ?

 

[AMink]

This is no longer any fun. Replaced the gasket, got a new nut after punting one, put it back together. It leaks worse now than before and the port plugs, I think they're brass, on the BD 2-piece leak. I tightened them and they don't leak as much but I'm afraid to screw them in any tighter. #@$%!

EDIT: Got new 1/8"NPT plugs for the manifold. Still leaks but not as bad. I even have bubbles coming up through one of the stud nuts when the exhaust brake is on. That, and I need to hunt down a new V-clamp for the turbo to e-brake elbow. How much is a new truck?