My exhaust manifold is cracked. How hard are they to replace?  Where is the best place to get one? I will go back with stock , unless that is not a good idea.

Go stock. There is no reason for a 3 piece. Rockauto has them for $125.00...

DORMAN 674602 

 

Agreed.  Stock.  

As for getting it off, I would definitely soak the turbo mounting bolts in PB Blaster a few days before attempting to remove them.  And the manifold bolts I'd soak in PB Blaster as well and then attempt to remove them when the motor is a touch warm (120* or so)

Edited April 19, 20187 yr by trreed

Don't use a wrench or a ratchet. If you can use an impact gun. Better chances of shocking it loose with impact than pulling torque on an already rusted fastener. I agree lots of PB blaster for a couple of days soaking. Block Heater is good for holding the temp up for you around 100-110*F.

Edited April 19, 20187 yr by Mopar1973Man

Thanks guys I will order one and get started.

https://www.genosgarage.com/product/manifold-5254373/exhaust-manifolds

 

might try local cummins for better price

Ordered it from Rockauto,. $121.00 with all gaskets and bolts.   Thanks for the reply.  Will I have to separate the turbo from the exhaust pipe to get it out?

You can drill and tap it for your EGT gauge before ever installing it.

You probably will have to take the downpipe off.  It'll be two bolts that face the ground.

If mine ever cracks I'll likely replace it with a 3 piece simply to avoid it ever cracking again and because the come pre-drilled.  Thats me saying that now though...

3 minutes ago, KATOOM said:

If mine ever cracks I'll likely replace it with a 3 piece simply to avoid it ever cracking again and because the come pre-drilled.  Thats me saying that now though...

I would go with stainless steel like  @jlbayes recommended 

17 hours ago, CTcummins24V said:

https://www.genosgarage.com/product/manifold-5254373/exhaust-manifolds

 

might try local cummins for better price

 

Still RockAuto at $125 got that beat...

19 minutes ago, Mopar1973Man said:

 

Still RockAuto at $125 got that beat...

 

Oem vs dorman. I haven’t been impressed with dorman in the past. Then again his OEM did crack

1 minute ago, CTcummins24V said:

Then again his OEM did crack

 

Typically guys without pyrometer gauges end up with cracked manifolds. Here I am with 340k miles and OEM manifold no issues. 

Everything is breakable.  It all boils down to the strength of the material being used (in this case quality of the cast and wall thickness), and use.  Guys who drive hard and shut the truck down right away will eventually see cracks due to excessive latent heat.  Guys who let the truck cool to 300-350* will usually see a longer service life.  

That being said, I don't like Dorman parts either.  In my experience, they are usually made cheaply and perform cheaply. 

Edited April 20, 20187 yr by trreed

7 minutes ago, trreed said:

Everything is breakable.  It all boils down to the strength of the material being used (in this case quality of the cast and wall thickness), and use.  Guys who drive hard and shut the truck down right away will see cracks due to heat cycling.  Guys who let the truck cool to 300-350* will usually see a longer service life.  

That being said, I don't like Dorman parts either.  In my experience, they are usually made cheaply and perform cheaply. 

 

Some of us are even smarter... Look at the turbo timer EGT setting.

I do have gauges,  I do tow heavy 15000# rv, case 580 backhoe,. I never let the EGT get over 1200 to 1300, usually around 1000-1100 towing

5 hours ago, Mopar1973Man said:

 

Some of us are even smarter... Look at the turbo timer EGT setting.

 

And some of us are even MORE smart...

 

Haha you guys are funny I'm sitting mine to 273 then I'll be the smartest oh wait what if someone sets theirs to 272 

9 hours ago, trreed said:

Everything is breakable.  It all boils down to the strength of the material being used (in this case quality of the cast and wall thickness), and use.  Guys who drive hard and shut the truck down right away will eventually see cracks due to excessive latent heat.  Guys who let the truck cool to 300-350* will usually see a longer service life.  

That being said, I don't like Dorman parts either.  In my experience, they are usually made cheaply and perform cheaply. 

 

Agreed everything is breakable and quality is generally the main variable why things do.

But over the many years I've always understood exhaust manifold cracking was nothing to do with shut down temperatures but rather because of high EGT's while pulling up hills and then going downhill off the throttle which rapidly cools the exhaust temperatures.  So that said, Its been suggested that people with exhaust brakes experience less manifold cracking problems simply because the exhaust brake keeps the EGT's hotter on the downhill ride.  Less extreme hot to extreme cool temperature fluctuations means less cracking.

Got my manifold from Rockauto, can anyone tell me what the plate is for?  Mine don't have this.