Fiberglass Fuel Tank (1971 Cj-6)?

I just took delivery of the 1971 CJ-6 fire Jeep I recently purchased. While taking inventory of what's there, and what will need some TLC, I wondered about rust inside the gas tank. It was a fire department Jeep, and has less than 5,800 original miles.

When I looked at the fuel tank, it appears to be made of fiberglass. I definitely expected a steel tank.

The fire department was the original purchaser of the Jeep, so unless they swapped it out for some weird reason, it should be the stock tank.

Feedback on fiberglass fuel tanks for this era CJ?

Thanks,
Craig

 

The original would have been steel. It may have rusted out from lack of use, the tanks are vented so humidity can get in. Water will collect under the fuel and rust out the tank, even with low miles.

Edit- the 71 would have had a charcoal canister and be non vented, but it was common for people to get rid of the canister and put on a vented cap.

 

Thanks for the reply, Grant. Yeah, that was my concern with a steel tank. I've never seen a fiberglass one, though. Mysteries of a new (old) Jeep...

 

check my edit

 

Is it possible they installed a poly tank? Or maybe fiberglassed the bottom due to rust pitting? Not saying there couldn’t be one but never heard of a full fiberglass fuel tank for a CJ.

 

My guess is that the tank is polyethylene (plastic) as suggested by nickmil above. Fairly common aftermarket option. Fiberglass really needs to be lined because additives in gasoline can attack polyester resin.
-Donny

 

Definitely not a poly tank, but @nickmil may be onto something with the fiberglass coating. I looked in more detail just now (rain subsided, and I have some daylight), and it's definitely got a fiberglass coating over the entire tank, top & bottom. That said, when I knock on the tank, it sounds like steel, and it sounds like the tank is empty...potential slow leak.

I ran the battery down trying to start it, but am charging that now, and also picked up some Ethanol-free rec fuel to see if I can get it going. More to come.

Craig

 

Magnet magnet magnet

 

Yes, sir! I'll definitely check that after the rain...rain...rain.

 

Magnets work in the rain.

 

I have a CJ5 Reproduction gas tank than developed a leak around one of the seams. I am sure it could be fixed but I won't fool with it. If you want it it is yours for the drive to pick it up. I am in Birchwood TN, so not too far for a road trip.

 

I certainly appreciate the offer, Oldpappy, but I'll most likely just buy a new tank. I'm building a small house right now, so I promised my wife that the Jeep wouldn't turn into too big of a project, or pull my attention away from house building.

I do see that Omix has a 15-gallon poly tank that's supposedly a direct fit, but I'm trying to figure out if there's a related/compatible skid plate for mounting.

 

If you decide to go with a poly tank I’d suggest MTS http://www.mtscompany.com/

They have lots of options and have been doing it for a long time. Plenty of people here have used them and like them. I would suggest using their fuel cap if you use their filler neck as it fits best imho.
OMIX gets mixed reviews at best. They might even be simply reselling the MTS products but I don’t know that.

 

I try to avoid anything with the "Omix" label on it.

 

Thanks, nickmil. I saw this Motor Trend article about installing a MTS tank into a CJ-6, and will definitely look into that in more detail. I didn't realize they offered a filler neck, as well. Thanks again.

Craig

 

G

Glad to help. Mike Boyink had/has a nice write up also on his SuperStretch Dutch blog from years ago. I think I have a link on my desktop. Will try and post it up here tomorrow.

 

I appreciate that. SS Dutch was a beauty of a vehicle, too!

 

Well, I confirmed that the fuel tank, is in fact, fiberglass. How do I know? Because I found a crack in the underside. I'm guessing the fire department replaced the tank at some point.

 

But magnets don't stick to fiberglass, if it's raining out or not.