i have a 99 xj sport i just put a new catalytic converter and straight piped it 3 weeks ago and the catalytic is turning purple in color. i also just put ngk plugs and cap and rotor with 8.2 mm wires. no check engine light on. anyone know what could cause the cat to turn purple like that. thank you in advance

 

is it turning red or just purple

 

not sure on red i just noticed today when i was walking up to it from work that it was purple.

 

i would assume it is getting red hot because metal dont normally turn that color unless really hot

 

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there is some pics its dark so not the best pics

 

anyone have any input

 

It looks like it may be normal discoloration of the brand new metal from the heat. It's running okay? You may want to run it for a while and then crawl under there and see if it is glowing or not.

 

yea im gonna try that tomorrow its running like normal. just doesnt look right if you know what i mean thanks for your input

 

a lot of exhaust parts have an oily preservative on them to protect them from corrosion during storage, etc; and when you first start running them it makes the metal get dark and you can smell it burning off. My magnaflow cat got all kinds of dark and now it's kinda reddish/muddy but it never got really hot or gave me any problems. Every new exhaust I've put on a vehicle discolors pretty much right away once it starts getting hot under normal operation. I've only ever done a few, but the ones I've seen kinda looked like yours at first, then got even darker or more discolored so unless you can tell it's getting really hot or you have performance issues, I wouldn't worry too much. Just check it after running it at temp for a while and see if it's glowing hot, like the other folks suggested, and if not then just keep an eye on it for a bit.

 

that's normal discolouration.
you see it more common in motorcycle exhaust or chrome hot rod headers.

i wouldn't worry about it in the least.

 

Alright cool thanks for your help guys

 

Ditto on normal discoloration.

 

That's a completely normal discoloration. Metal has the tendency to turn colors when heated up. As long as it's not glowing red/see through then you're ok.