I tried searching but couldn't find this specific problem..

I've been getting a code for an evap leak and I'm certain it's the gas cap.

I've tried two different caps, and they won't thread more than half way in. The threads are too tight to get even close to making a seal.

I tried lubing things up but no dice.

Ideas?

 

First, never ask a question without giving us the fault code number not what you guess it is.
If you have replace 2 caps and still have an issue, you are going in the wrong direction.

 

The code is P0455, and the issue seems to be the threading in the filler neck. It just seems too tight. Is it normal for the cap to still have exposed threads when fully tightened?

 

A 455 is a major evap leak that can happen from the engine compartment back thru the gas tank.
Try cleaning the threads on the fuel neck with a small amount of oil, see if that helps.

 

I lubed it up but it didn't get much further. Does it not normally screw all the way in? The gasket in the gas cap comes no where near close enough to the fill neck to create a seal.

 

Mine goes all the way in, it starts clicking and that is how I know it is on well. I got that exact code when it wasn't in all the way.

 

My 2003 D2 had this code when I bought it, and it had the same issue. I bought the cheapest cap they had at autozone, and the problem was fixed for about 6 months. Then it wouldn't screw down completely again, just like the OE. I pretty much just lived with it until I sold it, but my next plan was going to be to buy a new OE part.

EDIT: that is one nice thing about the LR3. Instead of throwing a code, the display pops up with a message that says, "check fuel cap." Actually it DOES store a temp code, but at least it gives you the nice reminder before it sets a hard code and turns the light on.

 

I'm gonna try sanding the threads on the cap down tomorrow and see if it makes a difference. I have an extra cap, so the worst that could happen is I junk a cap.

 

This is actually a recall issue that was done at the dealerships on the unsold stock, but was not performed on already sold stock. They either replaced the filler neck, or the cap, I don't remember. Mine does the same during warmer weather. I'm going to try steel wool on both sides as per a recommendation I read on this thread. But, remember to not let any sand paper or steel wool down the pipe.

If I'm remembering correctly, I believe they replaced the cap with a smaller circumference one.

 

I'm just going to sand the cap itself. The last thing I need is sand in my gas tank.. Should get a chance to try it out today.