I'm curious about this. My caps don't seem to be venting however when my truck was parked in the garage there was a fuel odour. There isn't anything leaking and the smell didn't seem to be coming from the engine area. I'm wondering if maybe the gas caps are shot?

 

Next weekend, first thing in the morning, move it from the (cool) garage to the (warm) driveway. After about 30 min, go out with a piece of hose (stethoscope) and listen for any hissing near the gas caps. It's sort of like checking for a vacuum leak, but you're looking for a pressure leak.

 

I have never had a cap wear out but it could happen. More likely is that one of your emissions hoses to the vapor recovery cannister is loose or worn thru. Or you may have a leaky filler pipe.

I have had two cars that had the rubber filler pipe get old and become leaky. The rubber hoses to the cannister also can wear out for the same reason.

Good Luck,

Jim Henderson

 

Hmm yeah I was thinking of the cannister. The truck has a lot of miles but I wasn't sure how the cannister "wears out".

 

the cannisters will break down with age. Try replacing it. I had one that did the same thing and when i pulled it out it was filled with a gassy oily gooey mess.

 

I actually failed emission testing a couple years ago because my gas cap was leaking. Had to go buy a new one and retest. I could not believe how hard it was to find a gas cap that was in stock for an '85 Bronco. How many millions of Ford trucks are on the road that take that same cap?

 

Interesting. I did see some replacement caps out a local Canadian Tire, only $7 each cdn. I may grab two of those and see about a new cannister, any idea how much they are worth?

 

If your carbon canister sounds like it has dry powder in it, there's no reason to replace it. Ryan's must not have been purging, or been connected to the wrong hose to collect THAT much gas/oil. The carbon (activated charcoal) never "wears out" - it can get contaminated, or the case can crack, but otherwise, it'll last forever.