I will be needing a third gas cap for my 06 MCS. I was wondering if there is a better cap on the market or a mod anyone has done to keep from throwing the check engine light. As it is, these caps barely seal when new. I've tried different O rings. I've tried wiping the area dry after pumping gas. They seem to have a limited life and I'd like to find a more permanent fix. Any ideas?

 

given that my 95,000 mile 02 S never had this problem
and the fact that you have changed the cap
I'd suspect the problem is NOT the cap

maybe the top of the filler neck?
or the sensor?

 

I replaced the fist cap and didn't have the problem again for about a year and a half. Seems like the second one lasted just as long. I put a slightly beefier O ring in the first cap and it didn't do squat until I replaced it with a new cap. I guess $22.50 every year and a half isn't too bad, it's just the annoyance factor that drives me nuts.

The other thing that starts to happen over time, the O ring will start to leave a black residue around the lip of the filler neck. That will throw the light. Once that gets wiped and dried, it will seal again and light goes out. I'm wondering if it's the Sunoco gas eating the rubber. That's all I use.

 

As part of the emissions system, the gas cap should be under the Federal mandated 80,000 mile emissions warranty. Check with your dealer...

 

Hmmmm.... 2.5 years and 55,000 miles on my original cap and no issues...

 

do you use any octane boosters, seafoam, etc?

 

84,000 miles and no cap problems. Sounds like you have problems other then with your gas cap.

 

I've got 5:1 odds that his tank is not properly exhausting pressure from changes in heat. rather than going where it should, the expanding air heads up and busts the seal and trips the sensor. the gas fumes/vapor pressing upward eats away at your seal leaving the black residue.


thats just my guess.

 

Yeah I'm going to have to agree with the mass... 7yrs and 83,000miles and I still have the origional gas cap. You got other issues.

 

You definetly have some other problem. I've only replaced one cap in 5yrs.

 

I have been sworn to secrecy but I can't go on any longer....I must confess.

Bless me father....but we all have been taking turns swapping out our failed gas caps once a year for your lovely new one's....

Sorry about that -