Hey Guys! So long story short, my friends and I did an exhaust install today usin WD - 40 and after went for an aggressive drive to see how it sounded, got home and then noticed a slight white smoke coming from the engine back near the down pipe, what could this be? I'm honestly really nervous and when I was driving I was in high revs and accidently shifted from 1 to 4, silly mistake but I'm just worried it could be clutch or something more serious. Thanks guys.

 

What did it smell like? White smoke is usually water. Blue is oil. That miss shift is nothing to worry about. Go out and try to replicate it again.

 

on a new exhaust you can have the oils on in from when they manufactured it, they could be just burning off from the heat of the exaust....if thats the case it will go away, just keep an eye on it,

 

This. I had to take the exhaust manifold of my SR20 in my 240sx once b/c the shop that swapped it didn't source the anti-backout nuts for the turbo flange bolts. Obviously everything had been hosed down w/ penetrating oil, but the first couple of drives, I was certain that I had messed up my oil feed/return to the turbo (YAY!!! BANJO BOLTS!!) and that I was getting ready to have bits of T-24 all over the road.

White smoke would be coolant, typically, if it's an internal issue. Keep an eye on your oil to back sure it's not looking like a milkshake and your coolant level.

 

It did not smell bad, it honestly smelt a little like the wd-40 burning, and will do, it hand a good smell to it like sweeter, like almost the smell of coolant but not such, more like the wd-40 I used, I also used the gel one just so you know

 

Why did you use wd-40? That is more for preventing rust. Actually sucks as a penetrant. PB Blaster is decent, 50:50 atf and acetone is great, cheap, and you probably already have it in your garage.

 

No worries going from 1st to 4th...It's the other way that's a "money shift". If you're not getting white smoke out the tailpipes, you're probably o.k. To check, when the engine is up to full operating temp, hold a KLEENEX or similar paper tissue over a tailpipe. If the tissue gets destroyed, there's water in the exhaust.