Exhaust manifold broken bolts

[Rawze]

(07-20-2021 )tree98 Wrote:  You'll want to retorque those bolts after a couple days of running. Mine loosened up quite a bit but we're fine after the retorque.

One mistake i see a lot of mechanics make when re-mounting the turbo itself is that they will improperly torque the turbo mounting studs. Quickserv can be a bit mis-leading on what the proper torque values are. Here is the correct torque. They have changed the torque specs a few times in the procedures... here are the numbers that I use with best success ...

* For the newer VGT451 series turbo's on the CM2250, CM2350, the torque should be 48-ft/lbs. (shoud also be re-torqued after a few days run time due to its low value).

* For the older VGT500 series turbo's on the CM870, CM871, the torque should be 75-ft/lbs.

Seen a lot of 500 series turbo's that were only torqued to 45-ft.lbs and the turbo mounting gasket squealing like all h#ell after a while.

== and YES.... using a light coating / paint of hi-temp anti-sieze in ALL exhaust gaskets helps a lot with leak prevention. Reeming out the manifold mounting holes like the TSB mentioned above shows ... ensuring the manifold itself is flat and not warped, ensuring expansion jopints are not seized up, and Also using anti-sieze on the shanks of all the exhaust bolts where they are sleeved helps prevent them from snapping too.