Correct Gas Cap for 1965 Suburban ?

[Merican68C10]

Hey all,

I was curious if anyone knew what is the correct part number for an original style gas cap that fits a 1965 Suburban? I've tried searching the forum and can't seem to find any info or pictures that will help me determine. I tried one off of my 1968 C10 however none of them fit, they are too large in diameter to fit behind the gas lid door.

Any info and pics would be greatly appreciated!

[Southcity]

It's a good question, surprised that you have not received more responses on this. I have a 66 Suburban and had the same difficulty in finding an original style gas cap or just a gas cap that would work. My Suburban came with an aftermarket locking gas cap that never fit well and let fuel spill out very easily. A few things to consider:

1. As I understand it, stock 60-66 Suburban gas tanks do not have a vented line. I believe the original style gas cap would have been vented to help with this, allowing pressure to vent out as well as allow outside air in. I have no idea if these would allow fuel to seep out if the tank is full and driving some curvy roads.
2. There are a few threads that suggest just finding a cap that fits (vented or not) and then drilling a small pin hole in it. This does work but still allows fuel to seep out if tank is full and you drive curvy roads. It only takes a tiny amount of fuel to seep to smell like the entire tank is emptying itself onto your truck or ground.
3. There are some aftermarket caps (i.e Stant) that are vented but only allow pressure to escape, and most times the spring on the valve is a bit too stiff. Some threads talk about taking the cap apart, cutting a few coils from the spring so it is not quite as stiff so the vent opens more easily.

I am currently using a Stant 10640, it is vented but only to allow pressure out. I ended up modifying it by removing the vent spring so pressure is released but also let's air into the tank. The cap fits well but it should be noted I am also using an Edelbrock fuel pump on a 454 BB. I am not sure if the behavior noted above is different with a stock fuel pump/engine. I still get a little bit of fuel seep on it if tank is full and I drive curvy roads, the fuel starts sloshing around, shoots right up the filler neck and finds it's way out anywhere it can. I'm still on the hunt for a better gas cap.

[Merican68C10]

Southcity,

Lol I know right, who'd of thought such a much needed part would be so hard to find! I appreciate your response and the information you provided. I will keep in mind the trick with cutting the coil down if I run into same issue.

I was able to find a locking vented Stant that fits the fuel neck however I do not have the vehicle up and running yet, hopefully this weekend! I also was able to find an original cap but have not received it yet.

Hopefully one of the two will do the trick! I will say parts seem to be a little harder to come by for my new '65 Burb then my '68 C10.

Thanks again for reaching out, I knew SOMEONE had to know SOMETHING lol.

[Southcity]

Please keep me posted on the status of your gas cap. I'd say the biggest issue I have is fuel seeping out of the gas cap when the tank is full and taking spirited turns from left to right and back again. The fuel shoots up the filler neck and then seeps out a bit and even though it's not much, the odor is very strong.

Info worth mentioning about the Stant 10640 :
There is a check valve in the cap that allows air to freely enter tank as fuel is depleted, then closes, but if fuel tank gets too hot, check valve will open at approx. 10 in. vac. to release pressure . Supposed to prevent fuel evaporation and fumes from escaping.

I never ran the cap stock, I modified it right away but it's possible it may work in stock form.

[MusicMan70]

http://www.67-72chevytrucks.com/vboa...burban+gas+cap

Have you seen this thread on a locking cap style?

[Southcity]

That does look promising, has both vacuum and pressure release valves, I'll have to give one a try.

https://www.oreillyauto.com/detail/c...-cap/omp0/5091

[MusicMan70]

I have this tube going to the side of the top of the fill; does your Suburban have this? It also runs to the tank.

[ATTACH][/ATTACH]

[Southcity]

I do, as I understand it all the 60-66 Suburban stock tanks have this and I believe it is supposed to help with anti-surge when filling the tank. Fuel nozzle is blocking the opening, fuel is going down main tube and the smaller tube helps to vent/release pressure in tank.

[MusicMan70]

Thanks for that explanation, I just learned something!