So how worried should I be by these fumes.
October 6, 2012 6:41 AM   Subscribe

I just bought a 2007 Hyundai Elantra. I'm having some issues with fumes.

I bought this car in August. It has an issue where during start and sometimes during usage it will have engine fumes come out of the air conditing unit during startup and occasionally during use. I did have a check engine light after I accidentally put Supreme in. I resolved that used fuel system cleaner in the oil fill section and an oil change . I checked yesterday to see if there were any leaks by running it for 5 minutes on top of my concrete drive way. I did get some water leakage but no fuel leakage and it didn't appear to be coolant either. It does have 112,000 miles so I think it might be blowby but I'm not sure . Whats the worst case and the best case scenario. I really don't know all that much about cars but I'm troubleshooting the same way I do for everything.
posted by Rubbstone to Travel & Transportation (4 answers total)
"Engine fumes" Does it smell like oil, gas, or exhaust? Have you checked for an exhaust leak under the hood?
posted by Mr. Yuck at 7:51 AM on October 6, 2012

Response by poster: Mostly like exhaust.
posted by Rubbstone at 7:57 AM on October 6, 2012

You could have a small leak anywhere along the exhaust system. Take it to a muffler shop and see what they say.
posted by lulu68 at 8:13 AM on October 6, 2012

+1 to lulu68. YOu probably have an exhaust leak somewhere in the engine compartment that is getting sucked in the air intake vents (those slots at the base of the windshield). When you are stationary the exhaust fumes stick around the car and get sucked in, when you are moving (usage) the get blown away from the car.

Using supreme fuel will not cause a check engine light. Using a higher grade fuel than your car requires will do nothing, either good or bad, to the car. Most likely what caused the check engine light was a loose fuel cap or some other unrelated cause. The only way to be sure is to get the code pulled from the onboard diagnostic system port somewhere in the passenger compartment of the car (you can buy a simple one for about 50$ and it will be worth it if you are going to be driving older used cars) it pays for itself after about 1 time at the mechanic. It will give you a trouble code like p10007 that means something for your car. What I do is enter the make of the car and the code in google and usually find the problem in about 5 seconds. Which lets you know if the mechanic is lying to you.

The water leakage is a little troubling. Did you have the AC on? if so it would be normal to get the water from the evaporator, and should be coming from somewhere near the passenger footwell. If it is water from the exhaust system (the most common byproducts of an internal combustion engine is water and CO2) from your exhaust leak it is a BIG leak and the car will sound really loud and bad.

Did you put the fuel system cleaner in the place you put oil in the engine? if so you need to change the oil really, really soon, like 5 minutes after you did that. It will thin the oil and cause you much bigger problems, like a new engine. If you put in the gas tank that is where you should put it. BTW the best way to 'clean' the inside of the engine is to do several frequent oil changes (like every 500 miles or as soon as the oil darkens) until it doesn't darken very quickly (like 1000 miles). This can take a while and be expensive, especially if you aren't doing it yourself.

BTW this car is pretty simple and easy to work on, buy the haynes manual and a code scanner (my scanner) and most common inexpensive cars have a LOT of DIY fixes on the internet (this my be a good or bad board-don't know it is the first one that showed up in google) in a good step by step manner.

Good luck.
posted by bartonlong at 9:20 AM on October 6, 2012

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