This past winter my 2004 Rx-8 (owned from new, 70k miles, mix city/highway driving) began spewing billows of whitish smoke and 1970's-like exhaust fumes (akin to old junk yard car stench of start-up exhaust) in cold weather. Smoke and fumes continue even after temp needle starts moving. Not sweet antifreeze smell, or particularly gas-like, just plain old exhaust smell so bad that i had to close windows and open moonroof or suffocate. This was not only in 20 degree weather but even 50 degree weather, albeit less evident as weather warms. Colder the weather, worse the problem. Once car warmed up, not a problem.

I bought extended warranty when expensive repair needs (coils) began and dealer service manager has been very good - - i'm there enough - - but they cannot replicate or identify exhaust prob. i didn't get chance to bring car in during coldest months, but had car in well prior to 60 degree weather and dealer diagnostic machines found nothing. brought it in second time few weeks later (when wheel bearing went and a sway bar link broke re fell off) and complained to service manager re continuing though lessening fumes and asked they check plugs and replace if needed. they found plugs to be fine, and did a $70 throttle bottle cleaning service. Didn't help. Problem directly related to outside temperature for cold starts, so less and less apparent.

Car had all ignition coils replaced about 15k ago and gets regular oil changes and scheduled maintenance. Doesn't drink much oil - - less than I had anticipated. Did notice for first time this winter white goopy dipstick, but i attributed it to being just past 3k on oil change. I did notice about a month ago that car rpm's went very low during a stop for gas (i know, i should always turn off car to fuel but for some reason didn't that time...) and rpm's went so low car Almost stalled. has happened once or twice since, but not often. I don't often drive it very aggressively.

Any ideas what could be causing this and what else i can have dealer check? Or do i need to wait for winter weather and be there to cold start and show them? thanks very much!

 

sounds like you need to replace any and all the gaskets along your exhaust.

Check the seals from the cat all the way to the exhaust. You most likely have a leak somewhere along that area. The dealer doing a throttle body cleaning for the symptoms you described is like a doctor giving you an enema because you're complainging of a runny nose.

 

Thank you for taking the time to reply. i appreciate your suggestion and your humor, and will share that with the service manager. Should be entertaining.

 

it should be very easy for a service department with a lift to identify an exhaust leak. did they actually put it on a lift and check it out? ask them do so so if they haven't.

better yet, if they havent, think about going to an exhaust/muffler company since the people you went to are.... well at the least they are not being thorough and are wasting your time.

 

it should be very easy for a service department with a lift to identify an exhaust leak. did they actually put it on a lift and check it out? ask them do so so if they haven't.

better yet, if they havent, think about going to an exhaust/muffler company since the people you went to are.... well at the least they are not being thorough and are wasting your time.

 

Thank you Zoom44. The Mazda dealer definitely had the car on the lift, twice, as first they had to replace a type of heat shield that partially detached from the bottom of the car after hitting a wicked pothole. The second time they had it on the lift because they had to replace wheel bearings and a sway bar connector. They claim they cannot duplicate the exhaust issue. I'll be going thru state inspection soon, so if i get a big red failure sticker, maybe that will be sufficient evidence. I do like the dealer, i just think they're extremely conservative about fixing things if they cannot duplicate the problem and nothing is showing on diagnostic machines. But thank you kindly for taking the time to reply. I'll have another chat with the service manager.

 

what state? do they do a physical inspection or just plug into the car?

you are still having the issue after they fixed the heat shield problem? do you know which shield thsi was?