Gas smell - 1946 Ford Super Deluxe (flathead)

[Nicole F]

Hi again. First of all I want to thank all of you who have been so generously helping to educate me on my first classic car. What an amazing resource this forum is! You guys are the best!!

 

We are storing her in our large, 3 car garage (high ceilings) and there is a consistent gasoline smell (which is kind of a bummer because our gym is also in the garage 😑). I am assuming this is somewhat normal for these old cars? But how much is too much (and an indication of some sort of issue/leak)? 

 

Thanks a million!!

 

 

[dictator27]

Modern gasoline is much more volatile than when your car was new.  You may find that the float bowl in the carb is empty after the car has not been run for a few days because the gas has evaporated.  This may be the source of the smell if there are no signs of a gas leak anywhere.

[Nicole F]

1 minute ago, dictator27 said:

Modern gasoline is much more volatile than when your car was new.  You may find that the float bowl in the carb is empty after the car has not been run for a few days because the gas has evaporated.  This may be the source of the smell if there are no signs of a gas leak anywhere.

It does seem to be worse after driving and then is dissipates after a few days. 

[TerryB]

The fuel tank in your car is vented directly to the air, usually through a small opening in the gas cap.  Modern cars use recovery of vented gas fumes rather than air venting.  Small amounts of fumes can be expected.  Too much and you may want to look for a loose clamp in the fuel lines.

[Nicole F]

Just now, TerryB said:

The fuel tank in your car is vented directly to the air, usually through a small opening in the gas cap.  Modern cars use recovery of vented gas fumes rather than air venting.  Small amounts of fumes can be expected.  Too much and you may want to look for a loose clamp in the fuel lines.

Thanks Terry! I’ll take a look! 

[Grimy]

3 hours ago, TerryB said:

The fuel tank in your car is vented directly to the air, usually through a small opening in the gas cap.  Modern cars use recovery of vented gas fumes rather than air venting.  Small amounts of fumes can be expected.  Too much and you may want to look for a loose clamp in the fuel lines.

^^ What he said.  Nevertheless, it's a good idea to periodically put your car on a hoist and look for Things Gone Wrong such as deteriorated or leaky hoses, loose clamps, broken return springs.  While it's up there, check the level of the gear oil in the transmission and differential.  Take notes--with a new-to-you car, this becomes your baseline.  I also pack the front wheel bearings and do a full lube of any newly acquired car unless I receive a full service history with the car.  BASELINE--make a record and specify when you'll do that service again.

 

We've established now that your car does not have its factory mechanical fuel pump, so almost certainly there is an electric pump somewhere, which is *usually* connected to the system with rubber fuel hose, rather than hard-plumbed.  If it were my car, I'd change any and all rubber fuel hose now, on general principles and to establish a baseline (in this case, then I won't have to worry about fuel hose for another 7 years).  Fuel hose usually rots from the inside out and can put debris into your fuel system without you knowing it.  Spend a few extra $$ and replace with high-pressure fuel injection hose, SAE30R9 (rather than R7), for MUCH longer life.  Follow the fuel line from the tank forward, looking for wet spots.

 

Look also at the fuel filler neck where it enters the tank.  I don't remember whether you have a large diameter fuel hose connecting the neck to the tank--some cars do.

Edited May 23, 2022 by Grimy
fix typos (see edit history)

[TTR]

16 minutes ago, Nicole F said:

... there is a consistent gasoline smell ... I am assuming this is somewhat normal for these old cars? 

Yes, comparatively to modern vehicles, exposure of fuel odor is noticeably more apparent.

As described by TerryB, modern vehicle fuel delivery circuits (from tank to induction) are relatively enclosed with any (but minimal) external evaporation fumes processed through carbon filtering. etc. 

Older/Vintage cars, like your '46 Ford with carburetor(?) and traditional fuel tank, etc allow evaporation fumes "escape" directly to atmosphere.

 

29 minutes ago, Nicole F said:

But how much is too much (and an indication of some sort of issue/leak)? 

Impossible to assess or determine via internet, at least through my computer. 😉

[Mark Shaw]

The metal seated float valves in old carburetors will often weep gas due to wear or due to a float that has lost some of its buoyancy.  A simple shut-off valve ahead of the fuel filter and carburetor provides peace of mind and makes it easier to change the fuel filter.

 

[JamesR]

2 hours ago, Nicole F said:

....there is a consistent gasoline smell (which is kind of a bummer because our gym is also in the garage

 Again, as others have said, this is something that's normal for old cars - within limits - and is mostly because of the old simple tank design. My recommendation is to get used to what is typical for your car so that you can tell when the odor is too strong...an indication of a fuel system leak. I'm guessing that someone like Matt Harwood - a well known classic car dealer who frequents this site - could provide some insight on how to keep gas fumes in an enclosed space at a minimum.  I was in a great old car museum in the Midwest with my wife about a week ago. 95% or better of the cars were in running condition according to the volunteer attendant. I'd say that most of the cars' gas tanks were kept empty, because it wasn't nearly as noxious as it could've been. OR they had a really good ventilation system.

Edited May 23, 2022 by JamesR (see edit history)

[m-mman]

1 hour ago, JamesR said:

I'd say that most of the cars' gas tanks were kept empty,

Your collector car is new to you and you are enjoying it, so you probably keep a supply of fuel in it. (half? full?) 

Those of use who have several collector cars and no one car in particular is used regularly, typically store them as empty as possible.

 

Yeah, we risk running out on the way BACK from an event, rather that have too much fuel in it for months at a time. 

 

Modern gas evaporates quickly and leaves all kinds of sticky gunk in the fuel system that can cause problems and is difficult to clean out.  As you learn your car, you will associate the gauge reading with "about to run out" and that's where you want it when it gets put away for a while. (months and months that can turn into years) 

 

But for now you are driving it regularly so keep gas in it and enjoy it.

But get used to the odors as described above. 

Edited May 23, 2022 by m-mman (see edit history)

[charlespetty]

My 1947 Lincoln Continental smelled the garage up with a strong gas smell every time I filled the tank full, but not once the gas level in the tank fell below about 3/4 full.  Turned out the gasket around the fuel gauge sending unit at the top of the tank had failed thereby letting gas from a full tank slosh around and dribble down the side of the tank from the sending unit.  Once I replaced the gasket and carefully sealed the sending unit opening, no more strong gas smell.  

[Bhigdog]

Having a 70ish year old car is like having a 16 year old daughter. Nuff said.....bob

[Nicole F]

6 hours ago, m-mman said:

Your collector car is new to you and you are enjoying it, so you probably keep a supply of fuel in it. (half? full?) 

Those of use who have several collector cars and no one car in particular is used regularly, typically store them as empty as possible.

 

Yeah, we risk running out on the way BACK from an event, rather that have too much fuel in it for months at a time. 

 

Modern gas evaporates quickly and leaves all kinds of sticky gunk in the fuel system that can cause problems and is difficult to clean out.  As you learn your car, you will associate the gauge reading with "about to run out" and that's where you want it when it gets put away for a while. (months and months that can turn into years) 

 

But for now you are driving it regularly so keep gas in it and enjoy it.

But get used to the odors as described above. 

Interesting! That’s good advice for when we put her up for the winter. Do you guys use any fuel stabilizer (we put that in the motorcycles for winter storage)?

[Grimy]

5 minutes ago, Nicole F said:

Interesting! That’s good advice for when we put her up for the winter. Do you guys use any fuel stabilizer (we put that in the motorcycles for winter storage)?

I use "Startron" enzyme-based stabilizer from a marine store and have found it better than even blue (marine) Sta-Bil.  It's pricey (about $40/qt in CA but also available in pint bottles) but the dose is 1 oz per 8 gallons.  Pour additive in at gas station just before beginning fueling, so the pressure and volume from the nozzle will mix it properly.

[Nicole F]

3 hours ago, charlespetty said:

My 1947 Lincoln Continental smelled the garage up with a strong gas smell every time I filled the tank full, but not once the gas level in the tank fell below about 3/4 full.  Turned out the gasket around the fuel gauge sending unit at the top of the tank had failed thereby letting gas from a full tank slosh around and dribble down the side of the tank from the sending unit.  Once I replaced the gasket and carefully sealed the sending unit opening, no more strong gas smell.  

That’s a gorgeous car! One of our cousins in ID has the same model and year - convertible. Much fancier than the economically marketed super deluxe. 😉 I think they did a lot of modifications to the engine though - it’s an automatic transmission, which isn’t listed on the specs. I have a pic of the engine and it makes mine look like a lawn mower! I read it’s 300hp!! Mine is like 100, which is less than my Harley Fatboy. Haha! But that’s okay. She’s just for cruising 😊

[Nicole F]

2 minutes ago, Grimy said:

I use "Startron" enzyme-based stabilizer from a marine store and have found it better than even blue (marine) Sta-Bil.  It's pricey (about $40/qt in CA but also available in pint bottles) but the dose is 1 oz per 8 gallons.  Pour additive in at gas station just before beginning fueling, so the pressure and volume from the nozzle will mix it properly.

Thanks so much! Will add this to my notes! 

[Nicole F]

1 hour ago, Bhigdog said:

Having a 70ish year old car is like having a 16 year old daughter. Nuff said.....bob

Sassy and temperamental. Check. 😉 

[EmTee]

16 hours ago, m-mman said:

Those of use who have several collector cars and no one car in particular is used regularly, typically store them as empty as possible.

OK, I'll be the contrarian on this subject.  FWIW, I try to keep my cars between 1/2 and FULL all of the time.  I also run non-ethanol gas, as 91 octane E0 is available locally.  During the winter months (Dec - Apr here...) I try to keep the tanks full to minimize air space and thereby condensation inside the tanks.  I haven't used any stabilizer and so far have had no issues.  I shut-off gas to the carb on my boat and run the carb dry for winter.  I don't do that for the cars because I will take them out for exercise on a cold, dry day when roads are decent and the gas usually evaporates from the carb fairly quickly after parking with a hot engine anyway...

 

That said, my cars are stored in a detached garage, so I don't have the same concern regarding smell, though I will say that aside from some smell immediately after parking them, once they're cold I don't notice any gasoline odor, even with full tanks. 

[MCHinson]

I agree with EmTee. I have two 1937 Buicks stored in my detatched garage along with a modern car. There is a distinct odor (not specifically just a gasoline odor) that comes from either of the 1937 Buicks when first parked until they cool down. As soon as they cool down, there is no odor.

 

If there is an odor of gasoline after your Ford cools down, I would suspect a leak somewhere. I would suspect a slight leak somewhere in a fuel line, the fuel pump,  or else the gas tank sending unit gasket. 

[TexRiv_63]

Most older cars will have some gas odor when hot due to carb design and ethanol issue. After driving my old cars I leave them sit outside for an hour and a half with the hood open, then run them in, that takes care of it. You should NOT smell gas all the time. As others have said, get underneath and examine every part of the fuel system for leakage, correcting anything wrong. 

[John E. Guitar]

If you decide to rebuild the carburetor a good place for parts is Daytona Parts:

 

https://www.daytonaparts.com/

 

I rebuilt the carburetor in my 46 business coupe with their kit and haven't had a problem since.

[nsbrassnut]

I'm in agreement with many of the above comments. I keep three cars in an inside garage. All with vented to air tanks with 1/2 to full of gas. There is no gas smell when the sit for weeks on end. And all have had the fuel lines replaced and checked regularly for leakage.

 

It would be good to inspect under the hood and under the car when you first drive it back in and look for damp spots under the carburetor, fuel tank or along the fuel lines.

 

Many electric fuel pumps put out too high a pressure for the older carburators and can actually overpressure the float and pump too much gas into the carburetor. If that is happening you may see dampness around or under the carburetor. If you see dampness, wipe with a rag and see if it smells like gas. If it does, then then either the pressure it two high or the carburetor is leaking.

 

The electric fuel pump may need a pressure regulator to be installed to bring the pressure at the carb down to 1 to 2 psi.

 

The original fuel pumps only delivered that low a pressure to the carb. And if a properly rebuilt is installed, you could throw away the electric and would be better off without it.

 

Also, electric fuel pumps should have a dedicated on/off switch so that the pump can be shut off in an emergency if needed.

 

Drive Safe

 

Jeff

[Nicole F]

I’ll have the mechanic check this out too! Thanks!!

[keithb7]

When you have been driving for a while and everything is at full operating temperatures a few things happen. 
 

The older carbs are multiple sections bolted together in layers. Like a sandwich with gaskets between the sections. As the gaskets age the carb area will be wet with some gas. A little sweating out.  The hot engine parts make it flash off and it stinks up the garage when parked. 
 

Even when that is addressed, all sealed up, when you park a hot car you get heat sink. The engine is off. The fan not turning now. You just parked it. Everything gets a little hotter for a while before it starts to cool down. The modern gas in the bowl starts to expand and vaporize. Its pushed out of various tiny fuel passages in the carb. Out the bottom inside the carb, near your throttle valve.  It dribbles into the hot intake manifold and vaporizes. Stinking up your garage for a while. Then when things cool down it stops.  Be sure to run non-ethanol fuel. It will help. Ethanol infused fuel boils-off at lower temps.  
 

You may be interested in going deeper into the topic here if wanted:

 

https://youtu.be/wcz7DNdfhd4

 

 

Edited June 5, 2022 by keithb7 (see edit history)