I started driving my Z this week for the summer, and I really haven't driven it much since I purchased it in Mar-2018 from a co-worker - I had other projects around the house that were prioritized for me

So this week of drives has been to shake down the car and started building the list of needed repairs. Among them, the Service Engine Soon light lit and I read the codes last night - 0455 EVAP leak.

Reading through relevant posts here and elsewhere, and I've reviewed the steps in the FSM to follow. I'm lacking a Consult-II emulator, so I'll have to get one of those (I have similar laptop based diagnostic tools that I use for my Volvo and VW, I just need to find the right one to use for the Z, now).

My Z is a 2005 with 125k miles and it was always parked outside. Plus, it sat for a couple of years before I bought it.

When I filled the tank this morning, I looked over the fuel cap seal and it looks old. There are no visible cracks, but I'm sure the rubber is severely aged.

So, my question: I realize I can replace the fuel cap (and I would get the Nissan OEM one), but I'm wondering if someone has identified a correct O-ring gasket that can be used to make this repair?

My searches have not turned up a match, yet, but maybe someone else has identified one that works. My motivation is: if the mechanical assembly of the gas cap is still functional, why replace all the assembly if only the seal is bad? The tether is still attached and working, the cap unlocks/locks and clicks, but maybe just replacing the gasket is enough to return a fully functional seal and I can keep an unnecessary piece out of the landfill.

But again, if there isn't a good seal-only option, then I'll get the Nissan cap assembly. Next chance I get, I'll see if the tank releases air when I unlock the fuel cap (I didn't pay attention to that this morning when I filled up). Oh, and add to the repair list putting a new Windshield Washer fluid cap on - the tether/hinge broke this morning and the cap fell down on top of the underbody shroud (I'm at work and can't pry everything apart to get at it until I get home).

TIA

 

I have a 2003 350z, got the same code when my SES light went on. I replaced the cap and that fixed the problem. I didn't investigate farther since the car is 16 years old and I usually replace parts (instead of fixing pieces) on a car that old.

 

i worked in automotive retail for over 10 years and never heard of being able to replace a fuel cap seal. Am sure someone out there probably does but honestly for the price don't think it is worth the hassle.
If you want to keep the oem strap so you don't lose your cap go oem or just pick up a name brand fuel cap from your local auto parts store for less than 10$

 

Thanks for the feedback. A new OEM cap will definitely be the path I take if I'm unable to located a suitable gasket.

The SES light came back in on my drive to work this morning. It will likely read the same 0455 code, and I pulled the gas cap over the weekend and had a look at the seal and the lip of the fuel filler neck - both could use some cleanup.

So I'll probably start there: polish clean the lip of the fuel filler neck, and then remove and clean the current gasket and then refresh it with some petroleum jelly and see what happens.

 

Petroleum jelly will act as a solvent and degenerate rubber and vinyl parts.

 

Hmmm...maybe some grease rubbed in and wiped off then, instead. At least to drive for a few days and see if it comes back.

 

After looking at the cap seal some more tonight, it's not just an O-ring, but has more of a U cross section. So just sourcing a Vitron replacement is not likely.

I'll wind up replacing the cap with an OEM part in the near future, then.

 

Just an update on this...I hadn't replaced the gas cap, yet, but I notice this week that the SES light is no longer on. Maybe there have been enough fill-ups this summer so far (and the removing/reinstalling of the gas cap), and that has allowed for a better seal at the fuel cap. If it comes back I'll just order up the new OEM gas cap.

 

And another update...

The OEM caps have been Out of Stock when I looked, and when they came back in stock they were around $50. As I was ordering some other parts from Rock Auto, I decided to order a cheap, $3.44 gas cap by Stant. When it arrived, it did not feature the OEM tether (I expected it wouldn't), but I saw that the features of the cap thread were the same as the OEM cap, and that the gasket shape was the same! I moved the new gasket from the Stant cap to my OEM cap (so I could keep the tether), and I've driven another 100miles or so with it and filled up - no CEL so far! So, this may be an inexpensive way to replace the fuel cap gasket!

 

A last update to this one...

After replacing the gas cap gasket (only), the 0455 DTC came back after a day or so of driving - drat!

Then, over the course of more driving, I had a the engine stall on the highway and come back, with a DTC for the crankshaft position sensor. I replaced all 3 sensors (crankshaft and both camshaft sensors) with Hitachi parts, and the engine continues to run great.

BUT, as part of trying to replace the camshaft sensors, I again removed the intake pipe between the throttle body and airbox in an attempt (failed) to get better access to the left (US driver) side camshaft sensor. I wound up accessing it from behind the engine, reaching from the passenger side. I reconnected the intake, reset the DTC (because of the crankshaft position sensor DTC) and started driving again. Lo and behold, since then I have NOT had the 0455 DTC return. So, maybe I didn't have the intake pipe or PCV hose connected properly, still allowing the 0455 DTC to trigger? I've driven at least 500 miles since replacing those sensors, so it's gone through the emissions test protocol at least a few times.

No more Service Engine Soon light illuminated = happiness!