I am looking-for a CAP for my diesel fuel tank.

The original was kinda flat and crome on the up-side.

Can't seem to find anything on the Internet.

Anyone have any hook-ups in the gas-cap world???

Mac: Had the same problem some time ago. Gary Carter came to my rescue. Auto Zone has a fuel cap made by CST Inc.(Cooling Systems Technologies)
#6818. Perfect fit for my diesel fill tube. NAPA does not carry this brand nor could they help me. Price was $6.95.............

Mac,I replaced the cap on our Regency with a Stant 11640. This is a vented cap which is what is needed on the tank. It should be available at any auto parts store.

Nick

Took Carl's advice on the CST's [and since there is a new AUTO ZONE here in town].

Passed-on the 6818 and replaced my *missing* cap with A CST 6023, which looks nearly exactly like the original without the dents. Vented and fits perfectly.

Thanks for the help!

Now I'm really confused, should I/do I, need a vented fuel cap ?? Looking at my current cap I don't think it qualifies as a vented model.....

Carl, most vented caps will have vented printed on the cap.

Nick

Does my unvented cap creat a vacumn? Is there any down side to not having a vented cap? such as the fuel gage not being accurate or fuel flow being restricked,etc.........

quote:

Originally posted by carlflack:
Does my unvented cap creat a vacumn?

Yes Carl, it "Could".

Most tanks are vented too. They allow air to suck into the tank as the fuel is removed. If your vehicle tips over, the tank vent has a check valve that should keep the fuel from leaking out.

Some vented caps have a PSI Vent built into them. If the tank gets pressurized, the psi relief will pop on the cap. A lot of Mack trucks are equipped with this type of fuel cap.

My thoughts, you probably won't have a problem, but if you use your coach, and you start to notice a loss of power, pop open the fuel cap and see if you have more power.

When I do a service on a truck, we blow air down the vents to make sure they're not plugged up. In a dual fuel tank (Most Trucks) this is important to fuel return and overfilling of one tank in a dual return fuel setup. Not something that is an issue with most RVs.

A long time ago I had a traveling job for which I used a '53 Packard. Returning from a job in northern Wyoming, I gassed up South of Jackson Hole. It should have easily gotten me home to Denver, but the car quit about 5 miles too soon. I went through some unnecessary machinations, suspecting a faulty fuel pump, etc., before I finally discovered the gas station attendant had replaced my original cap with a non-vented one. My not-faulty fuel pump had enough suction to collapse the fuel tank, after which I could never get more than 17 gallons into a tank that originally held 21.

Moral: On a '53 Packard you certainly need a vented fuel tank cap. Probably not on a later vehicle, including a Barth if it has a vapor control system that provides another route for outside air to enter the tank. But it might be better to be safe than sorry.

Interesting question. On my 85 Regal, the rear tank has a vented cap, but when the 'chief mechanic' dropped the mid tank (installed by Barth, not GM), she got a non-vented cap for it. Now, when I take off the cap of the mid-tank, there's a 'whoosh' as the vacuum is filled. With a Q-jet and engine driven fuel pump, me thinks I need a vented cap. Opinions?

Methinks you're correct.

quote:

Originally posted by Jim and Tere:
...me thinks I need a vented cap.

Me thinks you're going to break down if you don't. Put on a vented cap!

Spoke to John at CTS who confirmed that fuel caps #6818 and #6023 are VENTED. Auto Zone and O'Reily's, plus others carry their line....