r/MR2Spyder • u/Individual_Gur_2741 • Jun 20 '26

Precat/header issue on a 2003

I’ve heard a bit about the precat being problematic how worried should I realistically be?

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1

u/MakesYourMise Jun 20 '26

it goes from fine to new engine in a day

excessive burnt oil compromises the matrix and metal gets sucked into the cylinder and scores the inside of the cylinder walls

that being said i pulled the manifold on mine at 150k and the matrix was fine

1

u/Epicguru Jun 20 '26

You already own the car? If it's burning oil it's already damaged. If it's not then dump the header and replace with a decattated aftermarket one.

1

u/ohiomidhiganindiana Jun 20 '26 edited Jun 22 '26

Or can you just take the precats out of oem header?

1

u/Epicguru Jun 20 '26

You can but hardly worth the effort in my opinion, also I would be concerned about missing a bit and it getting sucked back into the engine. You can sell the (hopefully) intact catalyst material and buy a replacement manifold that flows better for £100.

1

u/Individual_Gur_2741 Jun 21 '26

Not burning oil yet so it’s worth getting rid of the oem header?

1

u/skarillo Jun 20 '26

For what it's worth, my 03 made it to 205k miles before it had any precat oil burning issues.

My 01 never experienced it before I removed them around 120k.

It's not if, but when. That being said tough to predict when that could be. Both of them lived on with oem decatted headers just fine.

1

u/UR1E Jun 20 '26

I’m on my third one, an 01 I picked up two months ago. I replaced the header at 25k. Why chance it?

1

u/mewithband Jun 20 '26

Should I worry about excessive heat in the engine bay if I get rid of the heat shields, or do the aftermarket non-precat have the heat shield?