Dear Scotty Kilmer,
I hope you're doing well. I have a 2018 Chevrolet Spark. I have driven around 25k miles on it and it drives like a dream. But one thing that I have noticed is a weird smell when I drove at high speed. It only happened 3x. I always drive in a city with a stop and go traffic so when I have a chance to drive it on a long stretch of highway with no vehicles around I always drive it at high speed. I heard it's good for the car I even watched your video about Italian tune-up. This smells happened at 90mph 3rd gear around 6000rpm before I shift to 4th gear (yes my spark is manual). After that, the smells go away. It's not a burning smell, I even thought it was my car perfume. My wife told me it's like a hair rebonding solution. So I am really confused, I never encountered, heard, or feel any problem in my car. I watched your video made years ago you said that if you smell something at high speed and you keep shifting gear and if you stop and the smells go away it's fine. Btw my car got infested by rats and also, we coated the bottom of the car with undercoat rust protection. Do you think that might the reason? Should I be worried?
I hope you read my letter. Thank you so much.
Kind regards,
Jeth
@jetchavz
At 90mph the coolant tank pressure may activate the overflow valve. The coolant would drip and create a smell with the plastics and the undercoating.
Can you tell where the smell comes from? (under the hood, under the car floor,...)
@yaser I'm not sure the car just got filled with that smell but it's not that strong. I test drive it two days ago, it smelled again. But this time I stopped, open then hood, tried my best to smell anything under the engine bay too but I can't smell anything.
The exhaust header/down pipe cold be getting pretty HOT at those high RPMs and possibly heating up that undercoating. That little spark engine has to be SCREAMING at that speed. Not made for that on a consistent basis.
@porkchophill this is what I'm suspecting actually.
It's just for one sprint (shifted at 6000rpm my redline is 6500). I know my car is not made for that, but it's just one sprint once in a while. If I were to say how many times I'm doing that, it will be once every 2 or 3 months.
MAN: Doc, it hurts when I do this.
DOCTOR:Then, don't do that.
Catalytic converter is getting extremely hot and super heating the underneath of the car.
One high rpm mis-shift and you won't be worrying about smell anymore...at minimum a piston skirt will break and then you have a deep knocking noise or you will see a connecting rod sticking out of the block.
The Italian Tune-up was to be driving the car at around 3000RPM. Not supposed to blow the gaskets. Run at highway speeds in high gear for awhile and go home.
The smell might be anything along the exhaust that you are trying to melt. Ah, the sweet smell of imported plastic.
