Disclaimer
The community here at 355nation.net urges you to please use caution and seek professional assistance when performing modifications to your vehicle. Before attempting any modification it is advised that you refer to your Colorado or Canyon service manual or contact a certified mechanic as not all GMT355 trucks are the same. The staff and the associated members are in no way responsible for any damages, injuries or other harm inflicted to your vehicle or yourself which may result in attempting these modifications. The posts and content presented on this site reflect in no way the views of 355nation.net or it’s ownership.
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A 355nation How To presented by
slicksteveo13
Project Name
How To Replace Exhaust Manifold Gasket/Doughnut Gasket
Project Description
Replace a worn gasket with a new one, to remove an exhaust leak or to keep the exhaust mid pipe from rotating and hitting the cross-member.
Skill Level
Easy
Project Vehicle
Make: GMC
Model: Canyon
Year: 2005
Engine: 3.5L
Power windows: Yes
Sun Roof: No
Tools Needed
1. Socket Wrench/Air Ratch
2. 15 mm Socket
3. Socket Extensions
4. Hammer
5. Prybar
![Image]()
Project Time
20 minutes or less
Project Cost
Gasket (I used from RockAuto.com, WALKER p/n 31531) $5.78
Make sure the truck has cooled off and the exhaust is not warm to touch.
Locate the exhaust manifold collector and where it attaches to the mid-pipe (the part of the exhaust with the catalytic converter
![Image]()
Using the socket wrench or air ratchet and 15 mm socket, remove the 3 nuts on the adapter.
![Image]()
Using the prybar, if needed, break the collecter flange away from the bolts
![Image]()
With the flange apart you can see the old gasket in there, it may also fall out when the flange is pulled away.
This is a comparison between the new gasket and old.
![Image]()
Take the new gasket and insert it back into the location.
![Image]()
There is a ledge on the manifold side of the flange where the gasket can be place on and it will hold itself in place.
![Image]()
Using your socket wrench or air ratchet and 15 mm socket, the installation of the 3 nuts onto the bolts of the flange.
![Image]()
Tighten the catalytic converter nuts to 50 N.m (37 lb ft).
![Image]()
The installation of the gasket is now complete.
*****One thing to not is that after a day of driving if not less, you will need to climb back under the truck and re-tighten the nuts on the exhaust flange.****
The community here at 355nation.net urges you to please use caution and seek professional assistance when performing modifications to your vehicle. Before attempting any modification it is advised that you refer to your Colorado or Canyon service manual or contact a certified mechanic as not all GMT355 trucks are the same. The staff and the associated members are in no way responsible for any damages, injuries or other harm inflicted to your vehicle or yourself which may result in attempting these modifications. The posts and content presented on this site reflect in no way the views of 355nation.net or it’s ownership.
A 355nation How To presented by
slicksteveo13
Project Name
How To Replace Exhaust Manifold Gasket/Doughnut Gasket
Project Description
Replace a worn gasket with a new one, to remove an exhaust leak or to keep the exhaust mid pipe from rotating and hitting the cross-member.
Skill Level
Easy
Project Vehicle
Make: GMC
Model: Canyon
Year: 2005
Engine: 3.5L
Power windows: Yes
Sun Roof: No
Tools Needed
1. Socket Wrench/Air Ratch
2. 15 mm Socket
3. Socket Extensions
4. Hammer
5. Prybar
Project Time
20 minutes or less
Project Cost
Gasket (I used from RockAuto.com, WALKER p/n 31531) $5.78
Make sure the truck has cooled off and the exhaust is not warm to touch.
Locate the exhaust manifold collector and where it attaches to the mid-pipe (the part of the exhaust with the catalytic converter
Using the socket wrench or air ratchet and 15 mm socket, remove the 3 nuts on the adapter.
Using the prybar, if needed, break the collecter flange away from the bolts
With the flange apart you can see the old gasket in there, it may also fall out when the flange is pulled away.
This is a comparison between the new gasket and old.
Take the new gasket and insert it back into the location.
There is a ledge on the manifold side of the flange where the gasket can be place on and it will hold itself in place.
Using your socket wrench or air ratchet and 15 mm socket, the installation of the 3 nuts onto the bolts of the flange.
Tighten the catalytic converter nuts to 50 N.m (37 lb ft).
The installation of the gasket is now complete.
*****One thing to not is that after a day of driving if not less, you will need to climb back under the truck and re-tighten the nuts on the exhaust flange.****
