Metal Baloon (Balloon) sound

[Rawze]

(09-28-2018 )Chamberpains Wrote:  ...
Someone either misinstalled it or did not torque the bolts properly...

The torque on the turbo mounting bolts to the manifold should be set to 75 ft-lbs for the ISX CM870, CM871, and a minimum of 60 ft-lbs for the CM2250 and the CM2350's. There are some older manuals out there with only a value of 45 ft-lbs because of out of date turbo's that are no longer used. This is too low of a proper torque for any of the VG/HX turbochargers that are used with them. Even the quickserv procedure is confusing to what the proper torque is. Here is an example of this confusion inside this CM870 manual. On one page it says this...



Clearly someone would see this, because it is the first occurrence when doing a search to what the torque should be. - A typical mechanic will search for this spec and then set out to under-torque the turbo, either setting it to 45 ft-lbs, or to 60-ft-lbs(better but still under-torqued). using the page I just showed. -- THIS IS INCORRECT!!!


Simply scrolling down through the procedure further, it actually shows the correct torque of 75 ft-lbs as seen on this page inside this same procedure ...



-- This is because the second reference to proper torque IS FOR the VG TURBOCHARGER and for the HX60 TURBO that have standard size manifold mounting studs!. -- THE PROPER TORQUE FOR THE TURBO MOUNTING BOLTS IS 75 FT-LBS for a CM870 or CM871!. Anything LESS and you get exactly the problem you are having almost every time.

-- for the newer CM2250's and CM2350's, it shows this...



Actually I disagree with this a bit. I still torque them to 70-75 ft-lbs when someone is here and i am working on their truck with them. This is because 60~ish is barely enough to keep the problem from happening. Even in this procedure, it says to go back and re-torque the 60 ft-lbs a second time. Likely because they had this same issues?


-- ASK your mechanic what he torqued the turbo mounting bolts to and see what he replies with. If he does not know off the top of his head, he HAS NOT LOOKED IT UP ENOUGH TIMES and is likely NOT doing a proper job!. and if he says 45 ft-lbs --- CORRECT HIM WITH THIS INFORMATION AND TELL HIM TO STOP SCREWING PEOPLES GASKETS UP!.


- Grab a torque wrench and check each of the 4 mounting nuts to see if they are 75 ft-lbs (CM870/CM871), or at least 60 ft-lbs if it is a CM2250 or CM2350. Most likely you will find one or more of them under-torqued. Once that problem sets in though, you have to pull it apart, clean the mounting surfaces again, and replace the gasket to get it to stop.

Tags:

turbo, turbo torque, turbo mounting torque, screech, metal balloon, proper torque on turbo