Good suggestion… if there is one. We still have no idea what year the Acura is, if the poster is a new owner of a used vehicle, or anything at all about the car. I wish the OP would answer the questions.
@db4690 I drive with ac off and recirculate on. Smoke test was done on exhaust system. Exhaust has distinct smell.
@boilerengtn AC works fine so no refrigerant leaks. Tested AC manifold pressures. I was checked for allergies to mold spores and nothing. MDX is 01 so 15 years old just starting getting me sick about 5 months ago when I switched from conventional to high-mileage synthetic oil. I flushed engine oil and replaced with conventional oil. Headaches and nausea went away but other systems still there. I have discovered that most conventional oils now are synthetic blends. I clean all my cars with just basic soap water no chemical detailing.
Still wondering if the OP has these symptoms in other vehicles and if other people have these symptoms in the OP’s vehicle.
The most dangerous component of exhaust, the carbon monoxide that everyone has mentioned, has no smell. And that’s the one that can cause all of your symptoms.
IMHO a smoke test is inadequate to test for a problem of this nature. The system needs to be at operating temperature and under normal exhaust pressures. IMHO a carbon monoxide detector or a combustion analyzer (which also measures carbon monoxide) is needed here.
But I sure wish you’d answer some of the questions. Like are you the new owner of this, a used car? There are things people do in their cars, like smoking and hanging scented items on the mirror, that can cause serious allergic reactions in other people.
I’m guessing there’s a small oil leak from, say, a valve cover, dripping onto an exhaust manifold and getting pulled into the HVAC system.
That could be the problem.
Recirculate should not be used except for quickly cooling off in very hot weather.
You could be choking on your own breath (CO2).
While a little fresh air comes in with recirculate on it might not be enough long term except at highway speeds.
@Mustangman True mostly engine oil leaks. Yet some minor transmission oil leaks. Mechanics have no way of detecting oil vapors. If you look at most high-mileage engine compartments there is evidence of oil mist/vapor soot. Oil vapors escape from all high-mileage vehicles. Oil seals only designed to retain liquid oil not gases… Also, most mechanics are not allergic to engine vapors otherwise they would not be working on cars.
I have a new car that gives me no problems. My family and friends suffer no symptoms
I suspect this vehicle has climate control and if it does why not do like most people and just set the temperature you want a leave it to do it’s job.
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Not true. Modern engines don’t have near the odor, especially at low concentrations, while still enough to cause problems.
@jtsanders Have purchased many gas sniffers with no results. If it were CO or exhaust gases my entire family would all be sick. It’s just me.
@the_same_mountainbik I tested car with gas sniffers while driving under load. It’s not the exhaust system. I don’t smoke and nobody has touched my car expect me.
Why do you drive with the recirculate on? I almost never use the recirculate mode, even in subzero weather. I prefer fresh air from the outside as opposed to the stale air in the car being recirculates. Nils Erik Walberg, an engineer for the Nash company discovered that bringing in fresh air from the outside pressurizes the cabin when the car is in motion. The cabin actually warms up more quickly. I would suggest taking your car’s HVAC system out of recirculate mode and see what happens as you drive along. I know from my class room teaching experience that if the air handler goes off and the air in the classroom isn’t exchanged, the classroom becomes very stuffy even if the temperature doesn’t go up.
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@VOLVO_V70 No one else is affected. I just need a 2-3 min of driving to get sick. Symptoms last for a few days.
@VDCdriver 2001 Acura MDX 220k miles. I didn’t know what was the problem but starting to notice similar problems with my 2002 VW Jetta 150K miles. The only thing in common is slight oil leaks at oil pump, oil pan, and perhaps rear main seal.
One more idea - once cars get over about 10 years old, I start smelling things that must be deteriorating interior parts, padding, carpet, that kind of thing. Those things can’t simply be fixed. Maybe just time for a newer vehicle.
Well, there’s a big part of your problem–you’re rebreathing the same stale air, over and over. Turn the recirc off and get some fresh air into the cabin!
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@asemaster It’s not CO since I most likely would be dead. I take my kids to school every day and they are fine. Oil additives are highly toxic but only a few people like myself have allergic reactions. I would consider myself hyper-sensitive. Many other vapors get my sick such as hairspray, nail polish, and most detergent chemical vapors.
If the air in your vehicle is making you ill, why not open a window and switch on the ventilation system?
It seems half of my customers have a fear of fresh air, when I get in their cars the air is quite foul, I have to lower the windows immediately before driving into the shop.