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gas smell in my defroster


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timberghost
New User

Sep 19, 2007, 6:01 PM

Post #1 of 8 (18957 views)
gas smell in my defroster Sign In

hello guys, i have a 2001 pontiac grand am se 4 cyl. auto. when i turn my defroster on im getting a strong smell of gas. i dont smell on any other setting but defrost. can someone please help me figure this out. this car is driveing me crazyCrazy.. thanks and hope to hear some replys as to what the problem could be


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 20, 2007, 4:13 AM

Post #2 of 8 (18952 views)
Re: gas smell in my defroster Sign In

You mean "gasoline" right? The air that blows out the vents in your car comes from up by the windshield wipers and or from the interior - lower middle to passenger's side under the dash. If you smell raw fuel you need to chase down all the lines that carry fuel or fuel vapor,

T



timberghost
New User

Sep 20, 2007, 5:35 AM

Post #3 of 8 (18951 views)
Re: gas smell in my defroster Sign In

yes sir, raw gasoline smell, it is only smells when i turn it to defrost, heater and a/c is fine,no smell of fuel, its just when its on defrost blowing on the windshield,, how can it do this? how can it smell on defrost only and not in any other settings? your reply is greatly appreciated. thank you kindly...


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 20, 2007, 6:53 AM

Post #4 of 8 (18949 views)
Re: gas smell in my defroster Sign In

It doesn't take much gasoline to make an odor. Ever get some on you filling up and it stinks up the car for a while?

I can't think of a good reason for it only to happen on defrost setting except that it is closer to your nose. There is a passive fresh air flow thru cars that comes in and goes out usually thru door jams. A line with a leak underhood could get smell into the cabin. Most air around engine is channelled away from air intake areas. Some minicule leaks can evaporate before they make a drip and hard to find. I look for these by running my finger under suspect areas to see if it can get wet with fuel and look for areas that may be clean if gas has dripped there it would tend to clean the area it dripped.

There are sniffers that may pinpoint a tiny leak like ones they would use for gas (natural or propane) in plumbing or the leak finders for a/C refrigerants could sniff out a leak of fuel but if it more than minor the sensor would just sing away about anywhere near and not pin point the leak. I might even try to powder the fuel lines and components and see what gets cleaned off quickly. Not sure what else to suggest,

T



timberghost
New User

Sep 20, 2007, 10:07 AM

Post #5 of 8 (18948 views)
Re: gas smell in my defroster Sign In

i'll do that and see if i can find a leak, it idles at 1200rpms and i get awful gas miliage for a 4cyl engine.14 gal. of gas and i gets 250 miles out of a tank of gas, not sure about the high idle issue either. but i really appreciate all your help


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 20, 2007, 3:22 PM

Post #6 of 8 (18947 views)
Re: gas smell in my defroster Sign In

This high RPMs could be a vacuum leak and if so fixing that would get you better mileage. I can't think of the connection between that and the fuel smell right now??

T



timberghost
New User

Sep 20, 2007, 5:31 PM

Post #7 of 8 (18946 views)
Re: gas smell in my defroster Sign In

i searched high and low for a vacuum leak today and a fuel line leak also and no luck with either. if you think of anything to try please let me know,, you been more help than anyone.. thanks i appreciate it also


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 21, 2007, 5:19 AM

Post #8 of 8 (18944 views)
Re: gas smell in my defroster Sign In

What I'm thinking about is the two problems?? Are they related? Hmmm? Funny about the odor as odors can be hard to describe. Raw gasoline is pretty easy and common. I don't know YOUR nose! Anti-freeze has an odor that can come from heater core. It has a smell more like "gatorade" and makes windows get a film that is fussy to clean off. Gasses used for A/C are not supposed to leak and they are chiefly odorless. The oil used in A/C could make an odor but you didn't complain about your A/C not working so that's barking up the wrong tree right now.

Vacuum leak can be elusive to find. Hoses for vacuum use plastic things and plastic lines from rubber and the plastic ones look like electrical wires. The vac leaks can be at gaskets too or from the brake booster or line to it.

You can find unseen vacuum leaks by spraying carb cleaner sparingly at suspect spots CAREFULLY as hot parts can make carb cleaner catch fire. It will evaporate and be fine if you wait a bit. If you try carb cleaner/throttle body cleaner is the same thing with an engine at idle it will react when it finds a vacuum leak by making the idle change or if bad enough stall the engine. Spray along hosing - gaskets to intake manifold etc and you should get NO reaction. Gotta check out the spot that may. Use care with carb cleaner as it isn't friendly to painted or rubber parts if used excessively and keep it off car's paint job!

PCV systems hold vacuum and they can also leak some engine oil. Anywhere engine oil (some greasy spots around an engine is written off as normal) if it gets burned by anything hot like exhaust parts makes an odor that can be confused with either an exhaust or perhaps fuel odor.

The connection to the two problems are this and this might be wrong: Raised idle - 1,200 is too much and will make the exhaust parts hotter and if caused by a vacuum leak or any reason will affect fuel economy. An actual fuel leak that does not drip would have little impact on idle or fuel economy.

I had an old car once with a defective gasoline cap that for years before I got it would make a gasoline odor when the car was just filled up and took right hand turns?? Car was very old - good shape - owned by an in law far away from me and 10 different mechanics never found the source! I got this car and restored it and did find that the gas cap was wrong and could allow a couple drops of fuel to slosh out on one of those side flap gas door ways of placing a gas fill spot and the smell went thru the whole car from the back of the car?? That's what it was though.
It was the noted right hand turn that led me to it as the fill was on left side and the fuel sloshed that way on a right turn - voila!

I'm pretty sure the defrost setting is using outside air as would heat or vent settings. I also think all passive air for the cabin comes in by gille area of the windshield wiper and yes engine odors can get past the hood seal intended to prevent that.

For a powder to find a leak I would use baking soda (also a good fire extinguisher) or those carpet fresh powders that are chiefly baking soda. Either would just rinse off later when you want so you didn't appear to be some nut who was deodorizing his engineWink

One more check point: All the plastic snorkeling that goes from air filter to throttle body should be intact with nothing lose or cracked as that causes problem in many vehicles.

This problem could be something else altogether but these things mentioned ruled out would be great. Good luck,

T







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