Few Issues - Water In Fuel, Gas Tank Vent Hoses, Oil

Hey all, hoping someone might be able to help with a few issues I’m having.

1967 CJ5 with the Dauntless V6. Only has 29k original miles on it. However it has some intermediate CJ5 modifications to it like the rear mounted gas tank.

I ended up discovering that I had water in the gas tank in August of last summer while storing it in NC. It was running great prior to that. Not sure how the water got in the tank…I was having some work done on it and it was left out in a rainstorm for a few hours, nothing too heavy but normal rain fall for a few hours. I don’t see any leaks in any of the fuel lines but the issue started to occur while driving home after the work was completed. Coincidence? Maybe…

The tank was about 3/4 full when left out in the rain, and it started running rough on the way home. Wanted to stall several times while accelerating from several stop signs. So possibly rain water got in from somewhere? That or I was thinking bad gas. Or possibly humidity while it was sitting for 4 months while I was working on it over the summer, however, I ended up eventually just syphoning out the fuel and found quite a bit of water in the tank. More than I would think would have been possible for the source to be humidity.

After getting the tank emptied and letting it dry out while garaged overnight, I filled the tank with fresh premium gas the following day. I overfilled it a bit and I’m attaching some photos and video of the gas leaking out of what I believe to be a fuel vent on the driver side of the tank. There are 2 spouts that come out on the side of the tank but at the very top. What are they for? Are they both for pressure/venting? Why 2?


One looks to have a nipple on it or valve of some kind and the other is long and tucked up high in the driver side rear wheel well. I started to wonder if water was getting into the tank through one of these vent lines (mainly the one that is leaking in the photos) but figured there was no way the amount of water I had in the tank was getting in through that. However, after the gas stopped leaking out of that valve, when driving around on bumpy gravel roads or taking 90 degree corners, I noticed that fuel was spilling out of that valve and I could see signs of it having poured out of that short drain hose. So maybe water is getting in there after all? Seems like a make shift valve but not 100%. Does that look like the correct valve or look normal to you all? More photos below…


With the fresh fuel and full tank, I changed the oil, oil filter and swapped out the spark plugs (which definitely needed it). However, it’s still not running quite right. It will idle for a bit when cold and if I have the choke on it seems to be ok but once I turn off the choke it wants to stall after a few minutes of idling. It was never doing this before.

I’m running Lucas Oil Hot Rod & Classic High Zinc SAE 10W-30. I put in 5 quarts per the service manual even though the dipstick shows 4 quarts on it. I’ve read here in the forum that the 4 quarts noted on the dipstick is regarding the oil capacity of the pan and that the oil filter holds the 5th quart. Is that true?

Any thoughts on what might be going on? Would the water have done any damage that I wasn’t able to correct by the steps I took? Do the 2 vent hoses in the gas tank have something to do with it? Maybe the system not getting the right back pressure in the tank due to something being wrong with those vent lines maybe and it’s not getting enough fuel? I added an 8oz bottle of Iso-Heet to the full fresh tank of gas but no difference as of yet…

When syphoning out the gas, I stuck a tube down the fill pipe and definitely felt something give way that the syphoning hose pushed through before I was able to get the syphon hose down into the gas tank to begin pumping the bad gas out. Maybe a screen of some kind? Would there be a screen at the end of the fill tube before the gas empties into the tank?

This has been a long winded post so I apologize and appreciate anyone taking the time to read it. Trying to troubleshoot a few items with this first post that I think could be potentially contributing to it running rough still and appreciate any insight.

So the above details and backstory boils down to the following 3 questions below.

1. What is the correct amount of oil for the Dauntless V6. Is it 5 quarts of 4 quarts?
2. Where could water be getting in, is it possible it did some further damage even though it was only briefly run for about 10 miles with water in the fuel?
3. What are those 2 vent hoses on the driver side of the gas tank?

 

Welcome, and good luck.

Pro-tip... Much easier to get clear answers if you ask one question at a time.

Meanwhile, I'd suggest adding a can of SeaFoam to your fuel tank.

 

1- 5 quarts
2- What Pete said. Hard to say where the water came from with no history of this jeep.
3- Remnants of the emissions plumbing from a later model tank. Look up the emissions from say a 1974-1975 to see what needs to be capped off.

 

Ethanol gas?

 

The connections on top of the tank are for the charcoal canister on later model jeeps. You can just cap them off.

Rough idle could be a lot of things but I would suspect water in the carb or a vacuum leak.

I use castrol syntec 10w30 but any good brand of oil will be okay. Your jeep only has 29k on it I don't know that zinc additive is needed. There are lots of opinions on this if you will just search our forum. My jeep uses 5 quarts as stated above, but you can put 4 quarts in, idle it for a minute or so, then shut it off, let the oil drain back down and check it yourself to see how much more you need. The older oil filters were fram PH-11style but the fram PH-25 style is smaller but will still fit.

I have had problems with gas in the tank way back when my jeep was parked outside a lot. These tanks are vented so humidity gets inside and condenses then sits under the fuel because water is heavier than gas. Over time this builds up. Just keep your tank full or parked inside and that will help.

Welcome to the site!

 

I would pull the hoses off. Cap one reroute the other. that vent line is bound to breath in dust and water spray from the tire, move it and put a small lawnmower filter on the end.
Ethanol absorbs water from the atmosphere when warm and it condenses overnight and does not get re-absorbed from the bottom of the tank as easily as from the atmosphere above (temperature changes on the surface faster than the bottom).

My jeep has a boat filter with water drain for this and the TBI conversion. We have a lot of water crossings around here so I had to plan a little myself.

 

Nope, it was Non-ethanol gas

 

Thanks homersdog, appreciate the feedback, especially on the 2 connections on the top of the tank. So neither one needs to serve as a vent? They can both be capped/plugged?

 

Really appreciate the feedback Jw60. I hear you regarding the longer vent tube that is routed up above/behind the driver side rear tire, that was my thoughts as well regarding it being another point for moisture sprayed up from the rear tire and dirt and grime to collect and fall down into the gas tank. Any recommendations for where to route it? I know user “homersdog” mentioned above to just cap both lines as they are not needed but sounds like you believe one line should remain as a vent hose but rerouted someplace dryer and cleaner. I was thinking about maybe a short vent cap on it. Perhaps that would allow vapors to vent but keep water and debris out? Something like this one below on Amazon maybe? Thoughts? https://a.co/d/13uJpHo

 

Mine are capped. If I vented them the garage would smell like gasoline every time there was a temperature or pressure change. -keep in mind the proper fuel filler cap will be vented one way to prevent vacuum in the tank when the fuel pump is drawing from it.

 

Gee, if only there was some kind of system to absorb the fumes, like, oh I don't know, maybe a canister of charcoal or something.

 

Here is one well thought out but maybe not the best solution... clif notes, take the vent line from an area with minimal liquid (filler neck) send it to the opposite side of the tank (labyrinth) then you can vent wherever you want a gas smell (intake filter housing where it will be burned)
http://www.billavista.com/tech/Articles/Fuel_Cell/index.html


Full disclosure.... I never hooked my vent line back up... it's tapped into the filler neck and goes under the bed somewhere and I still have a vented cap. But I do drain the filter occasionally.

 

Either of these would do the trick with both lines hooked up to it?

Option 1: Check out this page from Summit Racing https://www.summitracing.com/parts/ado-214-2294

Option 2: Check out this page from Summit Racing https://www.summitracing.com/parts/rnb-911-261

Also, what about a fuel filter hooked up to one of the lines with the other end open to vent? I assume that would work but wouldn’t prevent the fumes/smell of gas?

 

in my opinion the charcoal canister is just another thing to work around, and a properly set up earlier style will be perfectly fine.

that being said, if'n you're looking to get a charcoal canister, i've got one from my '79 nova that looks to be the same on as above i'd send you for the cost of shipping. no garuntee it's good, but it'd be cheaper assuming it did work.

 

Old jeeps and other vehicles without a canister and sealed system gonna smell like gas. Some folks are too young to remember.

 

I wish there was a Gasoline, gear oil, and horsehair scented candle.

 

That was the smell of happiness to me as a kid. Good times with my Dad.

 

I don’t mind the smell of a little gas if I’m being honest but looking to solve the issues I’m having with water in the tank and ensure the jeep still runs properly with whatever changes I make to the gas tank. From what I’ve read it’s not going to run properly capping off both vents. So looking to see if the fuel vapor canisters I sent above would work to get the system set up the right way. Any thoughts on that last post I sent above?

 

I would skip the vapor canister.

 

And Canvak canvas treatment.