I'm still trying to determine if locking fuel caps from previous models will work on the LMM. I drove a LMM yesterday and noticed that the fuel cap color is green. It's still a screw in cap. Are the standard (non-locking) fuel caps green or black on the 07 Classic or earlier? If GM changed the color then maybe they changed something else in the cap and previous year locking caps won't work.

My 2003 has a black screw on fuel cap. Good luck with your search.

I think the reason for green has more to with it being diesel. Kind of a subtle reminder.

I wouldn't go by the rule "if they changed the color then maybe they changed something else" because GM has been known to change things for random reasons when everything was the same before. Example, 2006 + trucks have a different antenna thread than the pre-2006 trucks. They switched from 7mm to 6mm x1, IIRC. The antenna is exactly the same, but they changed them anyhow. Seeing as how you are dealing with an issue of threads, i wouldn't assume anything with your fitment unless you find specs on it ;)

I'll check my 03 and 06's cap with my 07 for ya and let ya know.


:thumb:

Somebody said Diesel caps were different threads then gas caps. Well my 98 350 and my 02 D-max and my LMM are all the same, I just tried them. Hope that helps.

I think the color change on the cap is to remind you to use ultra low sulfer in the LMM.

I have an 07' classic and it's green.

Just a thought.

I think the color change on the cap is to remind you to use ultra low sulfer in the LMM.
That sounds reasonable. It sounds like all are the same cap. Thanks to all. Actually, I'm now thinking of using the standard cap and getting a locking billet door.

The green is for Diesel. My '07 Classic has a green cap.

The green is for Diesel. My '07 Classic has a green cap.
I think the green for ultra low sulfur as mentioned. I think the diesel caps have been black before 2007.

The green is for Diesel. My '07 Classic has a green cap.

My '07 Classic is green (with the words Diesel) also ... and those were manufactured pre-low sulfur. I think the suggestion that GM switched to green as a gentle reminder is probably correct.

When I bought my aux fuel tank down at RDS, the sales guy suggested I buy a locking fuel cap for the tank. They carry them at Wal-Mart (~ $8?). When I looked at all the gas/fuel caps at Wal-Mart, the differences were gas vs. diesel, locking vs. non-locking, and vented vs. non-vented. Couldn't see any difference in threads.

Just make sure that you don't use a cap for a gas engine, the valving in the cap is different between the two.

Just make sure that you don't use a cap for a gas engine, the valving in the cap is different between the two.
I did not know this.

I did not know this.

Actually I think it's ok to use a gas type cap on a diesel but not the other way around. Diesels do not use a pressurized fuel system like the gas vehicles. You can run around with the cap off a diesel all day, but a gas engine will throw codes if the cap is even loose.

Having said that, I'm not sure the treads are the same or not.