Odorless toxic fumes



Sorry, again not true. Seals are indeed designed to retain vapor. The crankcase of modern cars is designed to contain the gasses that get past the rings and route them back into the air intake to be burned. The same is true for fuel tanks which have similar seals that retain gasoline vapor as well as liquid. There are even sensors that insure this seal is maintained and will throw a check engine light to let you know when this no longer occurs.

What you are seeing in your engine bay is minor leakage from seals and gaskets as well as crud off the road from other cars and trucks that then gets blown around the area in normal driving. Not soot unless it contacts something hot - and then you will smell it. It is not odorless. Transmissions have vent tot the atmosphere that do not capture any vapor but release it. These are for expansion and contraction of the transmission. If there is significant vapor coming out, your tranny is in serious trouble and, again, you WILL smell it. These minor leaks can be easily fixed by replacing the offending gaskets and periodically cleaning the engine compartment.

You can see I’m not the only one who has replied this way.

Since you changed cars and fixed the problem went away, what is your point to all this? To convince us of your findings? To convert us to your cause? Your conclusion is based on lots of inaccuracies. I am glad you symptoms are gone. They were solved in a way I think most people would approach the problem - If it makes me sick, I shall stop doing it!


PVC=Polyvinyl Chloride
I assume that you are referring to the PCV valve, rather than any PVC that might be in the car, but in this thread, I guess that almost anything is possible…



That’s a good catch @Triedaq ! Humans are sensitive to vibrations in the 6-9 hertz range and that can make you nauseous. The frequency varies by person - weight, height, posture - and the OP may be sensitive to that.

I have experienced exactly that while developing a cars ride with electronic shock absorbers. One setting sets off the engine bounce making me nauseous, but not my co-worker. another setting upsets his stomach but not mine.

A story from the test and development of the smaller 1978 Chevy Impala from 1978. The windshield and rear window were “pumping” in and out at the same frequency causing the test drivers to stop and vomit. Switch adhesives for the windshield and it all goes away.


A couple thoughts;
As @Triedaq mentioned, I used to feel sick for a couple days after getting new glasses. I have also been in some industrial settings where I am certain there were mechanical noises/vibrations which affected me.
You mentioned a sunroof. Is there any chance the drains are plugged and the rain water is running down the inside of the pillars and saturating the padding under the carpet? I think you said you had passed a mold allergy test, so this may be barking up the wrong tree, but at this point… If you haven’t yet, pull back both the carpet and padding and really really look for any signs of moisture, not only near the pillars, but also under the AC in case its drain is plugged. And pull the back seat, and even the liner in the trunk.


Perhaps it would be worth trying an ozone treatment to see if that makes any difference, although I have no idea how much it costs to do that.


@oamadrigal, you answered one of my questions but not the other. I am curious how you cleaned out the AC compartment without taking the ductwork apart.

My other question was about the route you take. Have you driven in a different environment to see if you get sick? For example, if you currently drive through a city, then try a drive in the country or visa versa.

Allergies are about tipping points. For example, if you drive in the city where pollution is generally higher, and this car adds only a tiny bit more to the air inside the vehicle, that could be the tipping point for your allergies. A drive in the country may not reach the tipping point, just as driving a new car doesn’t.

If you drive mostly in rural areas, a nearby farm using a certain chemical could be the problem, but that should also be a problem in your new car.

Last new question, just how much do you plan on spending to find the source? All new seals in the engine and transmission will not be cheap. If you haven’t done the second timing belt change yet and want to keep the car, you can have all the front seals changed for only a few bucks more than the belt change itself and that could be worth doing. Rear mains seldom go bad but a new oil pan gasket might be justified, but that will cost even if done concurrently with the belt job.

A new cat and new exhaust system is pretty expensive. At this point, after 15 years of good service, I’d just let the car go and not spend a lot of money on it, but maybe you are just more curious than I am.


@Mustangman I get what you are saying. I am just trying to fix a car that dealer and mechanics can’t. There are so many things that could go bad in older cars it’s almost impossible to find fix short of replacing everything.

All engines out-gas because they are not perfectly sealed from any of the toxic fluids.

I don’t want to argue with you. I am just looking for solutions. Thanks!


I think this quote bears highlighting.


When I switched to synthetic oil I definitely felt sicker.

Is it possible that engine oil out-gassing combined with battery acid out-gassing could produce toxic odorless fumes?



No, they don’t “out-gas”. You are basing your discussion on a fallacy. Where did you get this information and why do you persist with this? I and others here have told you that engines are sealed by design as are fuel systems. Please provide proof of your assertion of the “oil vapor” problem.

If you wish to fix your old car, I suggest the following; Steam clean the entire engine and transmission. drive it for a dew days. Note where all the leaking seals are. Fix them with new seals and gaskets. If your exhaust system leaks, replace any portion that does, with new gaskets. Report back if the problem is fixed.


I think you have me confused with somebody else. I never suggesting disassembling the AC system. I never even mentioned the AC system. :relaxed:


Thats a quote from the OP’s response to you. I’m not confused. Well not about that anyway.


Right, Keith, the Op is responding to me that he did not disassemble the AC system and that it doesn’t make sense to do so… except that I never mentioned the AC system!
I think the OP is confusing me with someone who DID suggest taking the AC system apart.


Have you tried wearing a face mask?

Something like this might help you determine if it is something you breath or another issue. It’s only $20 to evaluate airborne contaminants as an issue. If you still get sick after wearing one of these, it isn’t what you seem to think it is.


Yeah, I think he is confusing you with my first post. I mentioned how hard it was to clean out under the evaporator in my 97 Honda Accord.


I agree with a good possibility of frequencies by Triedaq. I remember a documentary (Future Weapons?) of ultra low frequency non-lethal riot control. The results were disorientation, dizziness, and nausea. Not respiratory problems. Although I have never experienced these problems with a motor vehicle I have never came close to OP’s obsession (“beating a dead horse”) = $$ with finding the problem. They were concerned with selling the vehicle with a possible CO leak which was not the problem. I have had more than one vehicle where I just disposed of it. Salvage yard.


At least I’m being confused with someone intelligent! :grin:


There are many possibilities that are not related to oil fumes, but the fact remains that no matter the source of the discomfort, the OP is the only one experiencing them. His wife, kids, other passengers, and a number of automotive professionals are able to drive/ride in the car without any symptoms. This leads me to believe that the problem may not necessarily lie with the car.


I think you are very likely correct.


The argument is a compelling one. I’m inclined to agree.