Exhaust note changed?

[gimpyrobb]

So on the way home Thursday, I noticed a high pitched noise from my exhaust when laying into the "go" peddle. I thought maybe I melted the turbo as I run alot at 1200* but when I shut her down, the turbo spooled down as always, no new noises. Not sure what do check at this point, only other thing I could think of would be maybe a burnt valve? What are your thoughts?

 

[m16ty]

Did you're EGT or boost (if you're running a boost gauge) change? I don't have any idea what it could be but if it were me, I'd pull the intake and/or exhaust off the turbo and check the shaft for looseness and/or missing blades.

 

[gimpyrobb]

No change in egts, I don't have a boost gauge. Seemed to run no different, other than the noise. I'm just worried as I have a recovery to do on Monday. Maybe I ought to bring a spare turbo.

 

[DieselBob]

Might be a bad turbo bearing. They can start to make noise under load without a total failure. Most of the time if you burn a valve you pickup a miss more than a noise. Also check that there are no splits or cracks or loose clamps on the intake boots from the air cleaner to the turbo inlet. They can make some very odd noises at times.

 

[m16ty]

Check that turbo out before you head out on a recovery. You don't want that turbo to go down and the engine eat the parts or it starts dumping oil and the engine runs away.

 

[gimpyrobb]

You think I should swap it out to be safe? Is there anyway to tell if its bad without sending it to Ken or Jwaller?

 

[m16ty]

You should be able to tell by visually inspecting it and spinning the shaft by hand (making sure it spins freely and smoothly) and checking the shaft for looseness (side to side and in and out).

There will more than likely be a little movement in the shaft but it shouldn't be "flopping" and there shouldn't be any signs of the blades contacting the housing.

 

[gimpyrobb]

Now I am paranoid and will have to ship it out and have it rebuilt. DANG!

 

[DieselBob]

what m16ty said. A small amount of end play is normal 3~4 thousands. Any radial play, side to side or up and down is indication of bearing failure. If any wet area is noticed on the compressor side it would indicate seal failure and a chance to have a run away condition.

 

[WillWagner]

Gimp, Sounds like an intake or exhaust leak.
Check the hose and clamps from the turbo to manifold and the intake and exhaust manifold gaskets.

Turbo bearings don't make noise man. They aren't a bearing with moving parts.

 

[gimpyrobb]

Will do!

 

[wsucougarx]

Just curious, what does it cost to have one of these turbo's rebuilt? My '86 has a leaky turbo. It's dripping oil onto the starter

 

[gimpyrobb]

If I remember correctly, about $250.

 

[Flyingvan911]

If I remember correctly, about $250.

That's not too bad. Can most commercial vehicle shops rebuild them?

 

[gimpyrobb]

I dunno, Jwaller and Ken are members here that can do it. Why have a non-member do it?

 

[Stretch44875]

I was thinking about it after we talked the other day. I'd go with Will on this one, thinking it is something whistling in the intake or exhaust. Maybe something loose or maybe even something stuck in the intake filter housing? Wouldn't hurt to pull the intake off the turbo and check for play too.

 

[citizensoldier]

I was thinking about it after we talked the other day. I'd go with Will on this one, thinking it is something whistling in the intake or exhaust. Maybe something loose or maybe even something stuck in the intake filter housing? Wouldn't hurt to pull the intake off the turbo and check for play too.

I was thinking the same thing Stretch.. How old is the intake filter? It might just have started to clog up or a mouse made a home over the weekend.. How long has in been since the top end has been done on your motor gymp? Might have some valve timing issues??

 

[JasonS]

what m16ty said. A small amount of end play is normal 3~4 thousands. Any radial play, side to side or up and down is indication of bearing failure. If any wet area is noticed on the compressor side it would indicate seal failure and a chance to have a run away condition.

I had always understood that the up/down play to be relatively large compared to end play. See the below specs for the 5.9 cummins turbo:

end play min .001
max .003

radial clearance min .012
max .018

this is out of section 10 b series shop manual

 

[Srjeeper]

I must be dreamin....

Gimppy, you sir never stop amazin me. Just about the time I think i've heard or seen it all, you throw a change-up.

Since when do you worry about anything until after it all goes to heii ? I was beginning to think your were totally fearless in your endevors and I was an old 'worry wart'.

I honestly don't think your problem is something major. I'd be leaning towards a loose clamp or leak somewhere to cause the pitch change. Anytime a turbo ever gave out on me, there was never any question as to what exactly was going bad.

Another indicator of a turbo problem will be an increase in exhaust smoke. It will usually be a blueish white color and progressively get worse.

Wish you all the best...good luck and please keep us posted..

 

[DieselBob]

I had always understood that the up/down play to be relatively large compared to end play. See the below specs for the 5.9 cummins turbo:

end play min .001
max .003

radial clearance min .012
max .018

this is out of section 10 b series shop manual

Well I stand corrected. I am surprised that the radial clearance is that much. We never really checked it using any kind of measuring tool. Just went by feel. If you could move the compressor or turbine wheel (depending if you had the intake or exhaust side off) back and forth ever so slightly that was ok but you didn't want to feel any side to side play. Good info to know.