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Just took a good look at the engine on my '17 and the exhaust manifold piping (headers?) appear to be rusted. Car bought new from Les Standford in Michigan. I am not happy with the aesthetic appearance and am wondering if GM will cover under warranty?
That's an iron exhaust manifold. Only way to "fix" it is to remove the manifold, blast it, and then coat with Eastwood High Temp Gray.
Here's a header that I did 5 years ago, it's still rust free. Keep in mind however that rust on your manifold is -totally- normal. Everyone has it. No more under warranty than the fact the air in your tires is stale by now.
Ok, I was not aware it was cast iron, did not have this in my other cars. I guess most members' manifolds look like this then. I did not want it to affect resale in the future
Last edited by Leonrojo; Feb 27, 2018 at 12:17 PM.
Completely normal, however if you check there was a recent thread on this where someone had used rust converter to improve the appearance. I don't know how well this works, but it certainly would be easier than removing the manifolds and painting with a high temp coating.
This is why I don't spend much time looking under the hood. This saves money on chroming and painting otherwise functional items. But if you want to do so, more power to you.
There is a product that can help. Cost less than $10! It's called Rust Reformer and I bought at Walmart. Note it has a shelf life of one year. It works well on the muffler rust. If you haven't looked the welds on the pipes to muffler body are rusted! The area near the welds (called the Heat Affected Zone) is also rusted because the very thin aluminum layer on the "aluminized" 409 stainless evaporates away.
This is a PDF and pics below that show what can be done for low cost and about 15 minutes time. It IS NOT a paint and only affects rust, iron oxide and turns it a blue/black. Held up on my 2014 for 3 years. I tried on the exhaust manifolds but did not work as well on the cast iron but helped some.
It's just cast iron and not treated like the iron rotors. Sorry.
I used to have some "pasty," gray stuff for exhaust manifolds that lasted pretty well and slowed the rust process, or at least evectively hid it, but I've no idea what it was called. If I can find whatever might be left of it or come up with the name I'll edit to add here. Maybe someone else will generate it, or something similar.
Stainless after-market headers in your future? All the best.
Ok, I was not aware it was cast iron, did not have this in my other cars. I guess most members' manifolds look like this then. I did not want it to affect resale in the future
Not most, all. I have 1300 mile on my 2018. Its never been in the rain and has spent most of its life in my garage. The selling dealer kept it inside as well. Mine looks just like yours
Hmm, it's a lot more for ceramic coated versus plain steel. For a Vette long tube headers cost $700 coated versus $425 in plain steel!
Ceramic coating is NOT a simple process. Cast iron manifolds have been used from the 1920's and before! They are durable and can handle the high heat. The LT4 manifolds are not shinny 304 stainless. Not sure what alloy they are made from.
LT4 exhaust manifolds are Stainless Steel but still look brown! Perhaps a casting alloy similar to the 10% chrome 409 stainless the C7 exhaust is made from! If you want more information on exhaust stainless alloys you can click this PDF: http://netwelding.com/Muffler_Rust.pdf
Shinny 304 stainless tubing headers can be purchased starting at ~$1000!
I hate calling that rust. Because rust has negative connotations.
That is cosmetic corrosion. The material is designed to corrode on the surface and after that it ceases to corrode further. This is based on the material and is a function of physics and chemistry.
Your exhaust pipes are in the same boat.
Rust is something that continues to eat away at the material and it's not designed in.
Hmm, those expensive LT4 stainless exhaust manifolds don't look much better! Expect it is also made from a 409 type alloy. Corrodes slower!
The only reason most of the muffler and pipes look better is they have a very thin aluminum coating!
From my PDF. From supplier of "aluminized" 409 stainless steel showing their corrosion test.
One step better than 409 is 439 used by some car companies in Europe.
Rust inside engine bay
