Turbo noise/ bad bearings?

[JDMills]

I posted a question about this noise my truck has a while back, and thought I had the issue cornered.



The symptoms are: At a steady crusing speed, around 50/55 MPH In 5th gear, the turbo (I think, although I may be jumping to conclusions) has an occasional change in tone, or the whistling, changes to be abit more buzz like.



If I ease up, or accelerate the noise will go away, but If I do not change anything the sound continues.



I tightened the hose clamps on the turbo/intake connection, and now that I am thinking of it, I will check all the other bolts on the intake tract. Does any one have other ideas as to how I can isolate this noise. I am headed out of town, in a couple of weeks and would be much more at ease if the truck was not acting as it is.

Some one mentioned a headgasket. is there any way to pinpoint it before taking the truck apart? I had checked the impeller on the trubo, and it does not appear to be touching the housing in any place...



all thoughts are appreciated,

Jason

 

[dpuckett]

The turbo will change pitch in relation to load, i. e. pedal position and whether you are on flat, going up or down a hill. Turbos are really pretty simple- you have the bearigns, and you have the blades. As long as it spins freely, there are no shavings anywhere, and you dont have any end-to-end slack, and minimal up and down play, it shoudl be good to go.



As for the head gasket- if you are keeping your oil and water seperated, there is nothing to get real worried about. I drove mine for 10K mi (yes, two oil changes) with the HG blown. I had a noise under load that sounded like a cross between a screech (similar to a alternator, et al, bearing going out) and a chirping bird. I read on Diesel Injection of Pittsburg's site that in the N14s it is most likely the head gasket. I had elminated all other possibilities in my mind, and it turned out to be the HG. BTW- the head was within . 002" of true over the entire length, and the cross hatches were still visible in every cylinder.



i dont know of any way to check the HG without taking the head off. If your 93 is near stock and has been for a while, I would put it down the list of possibilities. My truck was a 90 model (early 91) and had 245K on it when the HG went south, so that moved it up the list.



WHat gears do you have? If 3. 54s, it could be a drone from the engine at 1750-1800RPM. Try bumpming the speed up to 60-65, and see if it still makes the noise. At the right RPM, under the right load, at the right air conditions, they can make some awful sounds.



Daniel

 

[JDMills]

Daniel,

Thanks for your imput. I will look again at the turbo, and be sure it is not touching anything. The coolant and oil are still seprate, at least they were yesterday, when I put a new waterpump on it. the truck has at least 200 K on it as the speedometer was broken/disconnected while the last owner had it... may be I have a head gastet in my future. might try to do it this weekend if the local dodge dealership can get the parts. .

Thanks again for your imput,

Jason