1970 Fuel Tank and Smell Question

[PatrickGMC70]

Okay, I realize I'm a newb and this question may sound a little dumb, but I have to ask:

When these trucks were new, I assume it was NOT normal for the cab to smell like fuel, right? I mean, I can't imagine someone plunking down a whole bunch of money for a brand new truck in 1970, and then being okay with their clothes smelling like gas for the rest of the day.

The reason for my question is that I recently replaced the tank, sending unit, fuel line, cab grommet and fuel cap in my truck (basically everything), and I still get out of the truck smelling like gas. (Yes, I checked and the sending unit seal is intact and seated.)

Now, the smell has been greatly reduced from the old tank, but nonetheless, I can't drive the thing anywhere without stinking. The only thing I can think of is that maybe the seat is permanently smelly now, but I don't think that's the problem because ALL of my clothes smell, not just my back and butt (the parts touching the seat)

I've seen a lot of threads where someone moves the tank to eliminate the smell - which is making me come to believe that people just put up with this back then. I find that hard to believe, but I'm hoping to find the answer here. Thanks in advance.

[Rodk65]

That is the way it was back in the day. It was a truck. It wasn't trendy, it was just a tool that you used to haul things. I recently purchased a 1969 and when I sat down behind the wheel the smells brought back my youth. To a time when air conditioning wasn't absolutely necessary, a seat belt was my dads arm thrown across my chest so I wouldn't crush my skull on a metal dash board. No steering assist, traction control, power brakes, or power steering. Riding in the back with my bothers and sisters to the drive in theater.

I purchased mine in Oregon and road tripped it home to Wisconsin. I forgot how it felt to have the gas tank slosh behind the seat and the smell of gas. It is not ideal and the smell is the reason that the tank was removed from the cab.

If it something you cannot tolerate then move it to the rear frame. Regardless of what you decide to do, just enjoy your truck.

[dhaymaker]

Sounds to me like you did all the right things, from the tank to seals, etc. But, I don't agree that this is the way it was. I've been buying, selling, driving, and working on these trucks for years and I've never experienced a fuel smell problem that couldn't be resolved. Yes, having the tank in the cab is certainly not ideal, but your truck should not smell like gasoline in the cab. The system is designed to isolate the fuel from the passengers and I believe there still exists a problem with one of your seals. I would go through the system again, I know it's a pain, but you can find and cure the problem, IMHO.

[PatrickGMC70]

Thanks. I'm learning that they used this style of gas tank for decades - I can't believe that it took them all of that time to figure out they had to move the tank - or that people put up with it for that long.

What are your opinions about whether this is coming more from the seat than the tank? I think the seat maybe contributing in a small way, but the source has to be the tank.


(BTW - I don't smell anything through the vents so I don't think it's coming from the engine compartment.)

[stevencvn72]

My truck had SERIOUS fuel issues when I first got it. If the gas has leaked and soaked the seats and carpet, your options are pretty limited. I removed and replaced the carpet and just cleaned everything else up after re-doing the fuel system. Remember...baking soda is your friend. Sprinkle it around and let it sit for a while before vacuuming <-(that spelling screws me up). I used a couple bowls of vinegar to set in there for a little while too. And finally, I keep one of those baking soda fridge thingies under the seat. Works wonders. Of course...none of this will work if you still possibly have a leaky system. And i've noticed if I REALLY top it off it has a tendancy to seep through the sender seal. So I try to avoid that....TaDa! Of course, after all that, the smell will never be gone completely.

[PatrickGMC70]

Baking soda is a really great idea Steve. Thanks I'll try that. Luckily, I don't have any carpet in the truck, just a rubber mat. I'll probably replace the seat cushions and cover at some point, but I want to make sure that the problem is solved first - no sense in ruining a brand new seat.

I get what you're saying about filling up the tank too much. I've filled it up once since I got it and the smell was pretty intense (though it was a pretty hot day). From now on, it will only go to 3/4.

Steve - are you saying that even after all of that, you still smell like gas when you ride in the truck? I'm trying to differentiate now from getting a whif of gas while driving versus getting out walking around the mall and smelling like a refinery.

[cdowns]

loads of smells in these old trucks come thru the firewalls and floorboards with excess unused holes bad grommets rotted holes and bad exhaust systems// a good cascap is a must so is a proper vent system// under the cab passenger side theres a piece of rubber hose that goes bad too

[PatrickGMC70]

Thanks for the tips. I did replace the rubber hose under the cab, but I am missing the floor grommet. I found a company that sells them, but they have a minimum order amount + loads of shipping fees. I haven't found anything at autozone that fits.

I also didn't check the rest of the firewall- I'll be sure to check on that too.

[swierker]

I guess I'm one of the lucky ones. I still have the tank in the cab and I never smell gas in the month that I have owned it. I've gone through at least 5 or 6 tank fulls.

So I agree that the smell in the cab is not the way it was from the factory

[raycow]

The in-cab tank was standard for a very long time and it was NOT normal to have gas fumes in the cab. It was moved outside only because of concerns about collision safety.

Have you inspected the joint where the fill pipe attaches to the tank?

Ray

[Jwill41]

I too have owned several of these trucks and have not had smell problems. The tank being in the cab does not bother me at all.

[fdbdw]

When I put in a new sending unit, I started to get a fuel smell. My guess is that over time the origanl tank, lock ring and sending unit marry together, when you start putting in new straight parts they dont seal as good even with a new gasket and a solid lock on the ring. I ended up putting a small bead of " right stuff " on the underside of the gasket ring, putting it in place then letting it dry , this not only seals the fumes but also keeps the ring from moving around while your locking the sending unit in place. Once its dry , only about 15 min, I put another small bead around the top and then locked the sending unit in place and never had a fuel smell again,

[1-PU70]

I agree with raycow. Had a few of thoes. I drove and worked on these trucks when they where new and there was no gas smell then.

[stevencvn72]

Originally Posted by PatrickGMC70

Baking soda is a really great idea Steve. Thanks I'll try that. Luckily, I don't have any carpet in the truck, just a rubber mat. I'll probably replace the seat cushions and cover at some point, but I want to make sure that the problem is solved first - no sense in ruining a brand new seat.

I get what you're saying about filling up the tank too much. I've filled it up once since I got it and the smell was pretty intense (though it was a pretty hot day). From now on, it will only go to 3/4.

Steve - are you saying that even after all of that, you still smell like gas when you ride in the truck? I'm trying to differentiate now from getting a whif of gas while driving versus getting out walking around the mall and smelling like a refinery.

I can't say I smell of fuel when I get out of the truck and the smell inside is pretty faint. Possibly from the chaos that was going on before I got the truck. I owned a '53 pick up a few years back and it had the same faint smell....perhaps that's why I didn't move the tank when I had the chance. Ahhh memories of high school girlfriends and the faint smell of gasoline...true romance!

[lil hoodlum]

My cab doesn't smell like gas either. I have the gas tank in the cab. I have replaced everything as well.

If I recall correctly, some trucks have an vapor line in the cab on the passenger side.

Also you might want to recheck the Evaporative Emission Control (EEC) vent hose if you have one. Tanks with EEC have a fuel hose on fuel neck.

Regardless, I would think the gas smell would disapate after awhile. Seems like you must still have a leak somewhere.

Good luck!

Keith

[PatrickGMC70]

Wow guys. Thanks for all of the suggestions. I'll find some sealer for the o-ring at the sending unit. Maybe it does just have to "grow together" with the other parts.

Raycow: I can't say I've inspected that joint, but the tank is brand new. I know anything's possible, but I'd have to pull the tank back out to really check that area.

In a way, this system is so simple, I can't see that there would be many causes. To me, the only real culprits could be the sending unit area and the seat being so saturated that it permanently stinks. I would think the fumes in the seat would eventually evaporate, but I'll try the baking soda to see if that helps.

And as for the sending unit, I KNOW it's not coming from the line because that is definately secure. I put it in once, backed it off, tightened it again a few times. That part is good and sealed. So, it's either the rubber o-ring, or the hole where the sending unit wire attaches. Except for the gas cap - there are no other places for fumes to come from.

I mainly wanted to check that this is NOT normal. I'm brand new to this era of vehicles, but this just didn't seem right to me. No offense to anyone on here, but I needed to know if the people that relocated the tank because of the smell just "gave up" trying to get it fixed, or if this was "just the way it was back then." It seems that I have my answer, so it's back to the garage to see what I can find.

[PatrickGMC70]

Well, I have a bit of an update.

I've had a few other people smell my truck, and no one smelled fuel. But they did say my truck smelled like "old truck." So I took the wife's new vacuum to the seats (let's just keep that between us), poured baking soda all over the seat, and then left a box of baking soda in the truck. For extra measure, I took the seat cover that we use in our other car for the dog and put that in the truck.

This weekend, I took the wife out for about an hour in the truck, and I can happily report that neither of us smelled like truck funk afterward.

So I'm cautiously optimistic that I may have solved the problem (and confirmed that I put in the gas tank correctly). I'll keep you guys updated on the progress, and hopefully the problem is solved. Thanks again for all the replies!

[stevencvn72]

Glad to hear you cleared it up!

[pat 70/71]

hey Patrick, check the evap line coming from the tank going to the canister under the battery thats where it was stock. GM used cloth type hoses to plumb the vents . over time they dry out / crack / smell! I had one truck that had a vent line that went over the back window in the cab for real! change out the old hoses to new fuel line & get ready to drive with no smell! hope this helps you. cheers, Pat

[PatrickGMC70]

Originally Posted by pat 70/71

hey Patrick, check the evap line coming from the tank going to the canister under the battery thats where it was stock. GM used cloth type hoses to plumb the vents . over time they dry out / crack / smell! I had one truck that had a vent line that went over the back window in the cab for real! change out the old hoses to new fuel line & get ready to drive with no smell! hope this helps you. cheers, Pat

Thanks for the suggestion, but my truck doesn't have an evap system. It has a non-vented tank with a vented gas cap. I had thought that if people responded that a gas smell is a fact of life with these trucks, my next step would probably have been to install an evap system.

In any event, I'm cautiously optimistic that my problem is taken care of for now. I'm travelling out of town so I won't get to drive the truck for a while, but I'm looking forward to going for a (smell-free) cruise when I get back. Thanks again.

Patrick

[eagleuh1]

I just had to replace the metal fuel line from tank to under cab. It had pitted just at the grommet, so tiny you couldn't see a hole, but it leaked a small spoonful of fuel out overnight onto my garage floor. Smelled fuel for 2 days, but couldn't find any leaks till I parked it in garage overnight. Now, no smell. Bent the old fuel line at the pitting and it just caved in. Glad that was caught before major leak, fire. Good luck with your fix.

[wzuke]

My leak drove me nuts for a year. I found it by accident. I had the line from the tank to the floor off (I was going to epoxy the entire line) and noticed that the flare was not properly seating. I replaced the line and the smell went away.

[treveiger]

Ya thats how they were i have the same deal with my 69, i love the smell of gas an when you close the windows an cruse the strip at night you start to get a really good feeling going an it also brings back memorys of my child hood, my dad had a 71 cheyenne when we were young an my grandpa had a late 60's truck an now i have a 69 c20 an never have any plans to sell it.
If i were you just sit back an enjoy the ride lol.