Exhaust smell , headache!

 

Hi guys, my 93 eunos has a lot of exhaust smell in the cabin, so i usually drive with the window open and its not to bad, i understand its probably due to the gearbox rubber thingy being corroded away, is that right?

what i woud like to know is why is it 20x worse when the roofs down, i drove about 60 miles with the roof down on sunday and was nearly physicaly sick due to the exaust fumes,

i have put my hand over the exhaust and theres no leaks, is it something to do with the aero dynamics or something that draws the fumes into the cabin when the roofs down?

cheers all

Adam

 

 

 G’day mate, welcome to the Forum

Always worse with the hood off, through draughts or something do the stuff in this procedure

air passing rapidly over the open cockpit is likely to create a vacuum/low pressure, thereby it is actually sucking the fumes up through any leaky bits in the cabin.  With roof up, air blowing in via vents is creating positice pressure so keep the fumes out…

I just made that up but I reckon thats it…!

 ??

I think you’re spot on but what the h+ll is  positice pressure /

 

 

Never had a problem, hood up or down. Would say there is a specific problem with the car. Do you have an aftermarket windblocker that could be giving turbulence?

I can’t see Mazda R&D leaving such a problem designed in to the car. Take your car to have the exhaust checked, any friendly fitter should be happy to stick it in the air and have a sniff!

it’ll have to be some pretty special aero dynamics that will suck air from the exhaust pipe up and over the boot, moving against the flow of wind over the car and into the cabin.  Likewise to get it to penetrate the failed gear lever boots.  Turbulence from air over the top of the car means you actually get blasted on the back of your head but I dont think this is enough to suck up air from behind and underneath the car where the exhaust is.  If it was a natural phenomenon due to the design of the car we’d all suffer from it. 

Experience on my last two cars that have done this are leaking manifold gaskets - at the head and the downpipe end, a hole in the downpipe or a cracked manifold.  And strangely, unlike a blowing silencer, the exhaust note didn’t change enough to suggest a failed exhaust.

 

 

 

well i took it to the garage and they said it was a cracked manifold,
so i got another one form a guy round the corner and decided to fit it
myself which wasnt to difficult. I think its better, but the car still
smells due to the previous problem and teh amount of fumes coming in.

I had a good look at the replacement
one and couldnt see any cracks, When i put my hand over the exhhaust
the pressure builds up till it forces my hand off. but i’m paranoid its still leaking in from somewhere.

The car does kick out a puff of black smoke when you depress the throtte hard and the tail pipe is very sooty. does this mean anything in particular?

thanks for your help guys

 

Adam