Exhaust Manifold Replacement (and heat shields?!)

[motorbreath]

A few months ago, after I had my front subframe replaced due to a rust-induced failure, I started to hear a small exhaust leak from the passenger-side of the exhaust manifold. After it getting noticeably worse a month ago, I took it to an exhaust shop which showed me that it was a tiny hole in the manifold where it reduces in diameter near the cylinder 1 flange. The previous owner had run the car without the underbody plastic shield, it seems the exhaust manifold is another victim of this abuse.

 

I bought/installed a Primitive skid plate late last year, so that should mitigate further rust. However, I am not able to get a new manifold until later this month (only 2 in North America!). As a temporary fix, I used J-B Weld 37901 ExtremeHeat High Temperature Resistant Metallic Paste, which has been working for the last 3 weeks.

 

Once I get the new manifold and turbo inlet gasket, I will send the turbo to get rebuilt (hopefully a BNR 18G) and upgrade the fuel pump, injectors, j-pipe, etc etc. One thing I am not sure about are the heat shields...now that I have a metal skid plate do I need all of them, some of them, none of them? All of the existing heat shields are almost completely rusted away.

[dgoodhue]

The primitive heat shield replaces the bottom, so it is not needed in your case. The top one does provide some heat shielding. If you want to replace the top one, the middle one will need to replaced because it is what the other heat shields bolted to. Personally I would replace them.

[dgoodhue]

Yikes on the manifold rusting out. None of the cars I have seen seem like they are anywhere near rusting out the manifolds. I guess that is why you subframe was rusted out. It seem like your car was subject to more corrosion than most.

[motorbreath]

I already did the repair, but it is a very tiny pinhole where the tube is welded to the flange, so I think it was the combination of being exposed to Canadian roads in the winter and a welding defect. The rest of the manifold is covered in rust, but structurally sound, so I think I am just unlucky

 

Yikes on the manifold rusting out. None of the cars I have seen seem like they are anywhere near rusting out the manifolds. I guess that is why you subframe was rusted out. It seem like your car was subject to more corrosion than most.

[motorbreath]

Looking at the parts schematic, it looks like the lower one is required in order for the top and middle heat shields to be assemble into a mechanically sound unit. I'll have to think about this, its alot of money and they are going to rust out again even with my skid plate, based on experience with my previous Outback in Canada.

 

The top one does provide some heat shielding. If you want to replace the top one, the middle one will need to replaced because it is what the other heat shields bolted to. Personally I would replace them.

[dgoodhue]

Looking at the parts schematic, it looks like the lower one is required in order for the top and middle heat shields to be assemble into a mechanically sound unit. I'll have to think about this, its alot of money and they are going to rust out again even with my skid plate, based on experience with my previous Outback in Canada.

 

The bottom bolts to the middle and top. It isn’t needed (no threads going into it). I have a 2010 GT engine apart, I looked at last week for another member asking a similar question.

 

Even though they rust out, they should last for another good 7-8 years.

[motorbreath]

OK, thanks, that will cut the cost down a bit, especially since the skid plate is already acting as a lower heat shield. Since you have one apart, would you be able to show me a picture of the turbo support? I can see that something is connected to the front engine mount area to support the turbo, but its so rusty I really cannot make it out.

 

I might as well replace this support once I pull the turbo for the upgrade later in the year.

 

The bottom bolts to the middle and top. It isn’t needed (no threads going into it). I have a 2010 GT engine apart, I looked at last week for another member asking a similar question.

 

Even though they rust out, they should last for another good 7-8 years.

[dgoodhue]

OK, thanks, that will cut the cost down a bit, especially since the skid plate is already acting as a lower heat shield. Since you have one apart, would you be able to show me a picture of the turbo support? I can see that something is connected to the front engine mount area to support the turbo, but its so rusty I really cannot make it out.

 

I might as well replace this support once I pull the turbo for the upgrade later in the year.

 

I am on vacation this week in Houston, but I would be more than happy to take some picture when I get back.

[motorbreath]

The bottom bolts to the middle and top. It isn’t needed (no threads going into it). I have a 2010 GT engine apart, I looked at last week for another member asking a similar question.

 

Even though they rust out, they should last for another good 7-8 years.

 

I'm finally getting around to this, I just want to confirm a few things:

 

1) That the two heat shields I should order (top and middle) are part numbers 44643AA000 and 44652AA930,

2) Would be a better option to buy a turbo blanket and either skip the heat shields or use both?

 

If item #2 makes sense, any suggestions on where to get a turbo blanket that would work for the VF54?

 

Thanks!

[dgoodhue]

I'm finally getting around to this, I just want to confirm a few things:

 

1) That the two heat shields I should order (top and middle) are part numbers 44643AA000 and 44652AA930

 

Yes, those are the part numbers.

 

As for the blanket, I am not sure you're going to find an off the shelf solution. I think it would have to wrap around the manifold. The heat shield at the very least are easier to install.

[motorbreath]

Awesome, thanks for the info!