Gasoline Tank Emitting Fuel Odor Inside the Truck

Joined
Apr 25, 2021
Messages
64
Location
Philippines
I wanted to eliminate that gasoline type of smell inside my truck. Over the weekend, i checked on the condition of my gasoline tank. Everything looks okay (all rubber hoses don't have gas odor) except for that odor i smell at the round-metal-type of cover on top of the tank where i believe the smell is coming from. Do the round cover and the tank in between has gasket for sealing? Any input is highly appreciated. Thanks
 
Last edited:
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Here's my tank am referring to...

20210809_140813.jpg
 
Joined
Jan 3, 2019
Messages
162
Location
Virginia
I have a similar problem, haven't thought about it much lately, and I don't know about your gasket question. But I wonder if it's safe to do that trick for finding exhaust leaks where you blow air in the fuel intake using like a shop vac and use soapy water to check for bubbles around hoses/gaskets. Maybe that could help find leaks? Anyone try that before?
 
Joined
Jan 9, 2020
Messages
354
Location
NorCal
I had this problem when I first got my 40. Make sure your tank is vented to the outside. The screws holding the sender look messed up. Buy some new ones with a lock washer and a regular washer for each. They may not be applying equal pressure on the sender.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
I had this problem when I first got my 40. Make sure your tank is vented to the outside. The screws holding the sender look messed up. Buy some new ones with a lock washer and a regular washer for each. They may not be applying equal pressure on the sender.

Thank you @Slapshot . Appreciate this. Can you elaborate a little bit when you say " make sure the tank is vented to the outside". Thanks again..
 
Joined
Jan 9, 2020
Messages
354
Location
NorCal
Thank you @Slapshot . Appreciate this. Can you elaborate a little bit when you say " make sure the tank is vented to the outside". Thanks again..
Depending on your year and emissions requirements, you should have 3 small tubes that run from your tank to a vapor separator that then vents to a charcoal canister. If this is missing and the vent lines are plugged, the expanding vapors will be forced out somewhere.
 
Joined
Oct 2, 2015
Messages
319
Location
Port Orchard, wa
Had a similar issue, and found the PO put gobs of goop all over everything, including around that sending unit, not only where is mated with the tank but also a heavy layer on top of all the screws. And goop all over all the hoses.

Turned out the venting was all mucked up. Get the correct emissions control system guide (I found enough info from partial scans on here) and verify the routing and function of the venting.

Mine has 3 lines running to a separator and a line from the separator going through a check valve into the charcoal canister. But the PO ran the hose from the separator to the charcoal canister into the tank's fuel return instead (carb did not have a fuel return), making it basically a closed system that would have to vent, well, not outside the passenger compartment and not via the charcoal canister....

And yes, there is supposed to be a gasket there. Please do remember gasoline fumes are explosive and don't kill yourself trying to remove the rounded out screw head with a drill.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Had a similar issue, and found the PO put gobs of goop all over everything, including around that sending unit, not only where is mated with the tank but also a heavy layer on top of all the screws. And goop all over all the hoses.

Turned out the venting was all mucked up. Get the correct emissions control system guide (I found enough info from partial scans on here) and verify the routing and function of the venting.

Mine has 3 lines running to a separator and a line from the separator going through a check valve into the charcoal canister. But the PO ran the hose from the separator to the charcoal canister into the tank's fuel return instead (carb did not have a fuel return), making it basically a closed system that would have to vent, well, not outside the passenger compartment and not via the charcoal canister....

And yes, there is supposed to be a gasket there. Please do remember gasoline fumes are explosive and don't kill yourself trying to remove the rounded out screw head with a drill.

All noted @kerplunk . Appreciate your inputs so much. Thank you. Will look for a Emission Cotrol System Manual for a FJ40 1974 Non-US version.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Depending on your year and emissions requirements, you should have 3 small tubes that run from your tank to a vapor separator that then vents to a charcoal canister. If this is missing and the vent lines are plugged, the expanding vapors will be forced out somewhere.

Got you. Mine is 1974 model, a non-US version and has a different emission system. Hope to find a manual for this. Thank you so much for your inputs. Appreciate much.
 

flx

Joined
Jan 4, 2019
Messages
365
Location
France
My Euro spec 1974 FJ40 did not had the emission stuff for the gas tank, just a simple vented gas cap. So I would believe that a general market FJ40 would be the same.
With pictures of the surroundings of your gas tank will be easy to say.

From observations I also believe (but not 100% sure) that from 1973, markets that had the emission stuff on the gas tank also got the fuel door. When you did not had the emission stuff you had a simple locking (and vented) gas cap, so it's easy to spot.

Note that with a vented gas cap when you fully fill your tank it's not usual that it smells gas.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
My Euro spec 1974 FJ40 did not had the emission stuff for the gas tank, just a simple vented gas cap. So I would believe that a general market FJ40 would be the same.
With pictures of the surroundings of your gas tank will be easy to say.

From observations I also believe (but not 100% sure) that from 1973, markets that had the emission stuff on the gas tank also got the fuel door. When you did not had the emission stuff you had a simple locking (and vented) gas cap, so it's easy to spot.

Note that with a vented gas cap when you fully fill your tank it's not usual that it smells gas.

Thanks @flx . You are 100% correct. I think mine has just a simple vented gas cap like what you have. Now i understand why everytime i open the fuel door, i immediately can smell fuel. I can now tell that the fuel odor that am smelling is just coming out from the sending unit (from that round metal cover). I just need to find the right gasket for that. Thanks again. Btw, i tried to view the pic of your FJ40 and am so amused to discover that it looks very much the same as mine like the ff parts: Wiper (installed at the upper side of the windshield), side mirror, door handle, winch, signal lights etc. All looks stocked and great.
 

flx

Joined
Jan 4, 2019
Messages
365
Location
France
Thanks, yes I try to keep it as stock as possible and 1974 is a very distinctive year.

Gasket should be available directly from Toyota, you can ask directly the partnumber to help them find it (or search on the Internet the best source) : 83361-20030
If you have to order outside of the Philippines I would guess that Amayama in Japan could be your best bet : Genuine Toyota 83361-20030 (8336120030) GASKET - https://www.amayama.com/en/part/toyota/8336120030

Seems the original screws are also available if you want to be fancy : 93319-14010
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Thanks, yes I try to keep it as stock as possible and 1974 is a very distinctive year.

Gasket should be available directly from Toyota, you can ask directly the partnumber to help them find it (or search on the Internet the best source) : 83361-20030
If you have to order outside of the Philippines I would guess that Amayama in Japan could be your best bet : Genuine Toyota 83361-20030 (8336120030) GASKET - https://www.amayama.com/en/part/toyota/8336120030

Seems the original screws are also available if you want to be fancy : 93319-14010

Thank you @flx . Will get in touch with this link you have provided. This will help a lot.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Hi @ToyotaMatt ,

I ordered 2 items from your company (VintageTeq Parts) with Order # 2559 since last week.

I don't have feedback yet on where they are now. Would appreciate if you can help me trace them. Thanks/Philip
 
Joined
Oct 2, 2015
Messages
319
Location
Port Orchard, wa
Remember that the tank has to vent somewhere.
If it's supposed to vent through the cap, make sure you have the correct cap and it can vent through it.
Modern cars usually don't vent through the cap, and if your cap was switched, it's going to vent out somewhere else.
While that gasket might be the weakest leak now, sealing it might just force the vent somewhere else if it can't through the cap.
 
Joined
Apr 25, 2021
Messages
64
Location
Philippines
Thank you so much @kerplunk . I take note of your input very seriously. Will discover if i have the correct cap for now . Thanks again...
 
Joined
Aug 14, 2016
Messages
71
Location
Round Hill, va
im in a similar situation. my '74 has the 3 lines on the tank connected to the vapor separator - with the output line connected to a check valve. I replaced the rusted hardline with fuel hose, and added an AC-Delco charcoal canister (since mine was missing). The canister has an air-inlet, and two nipples for TANK and PURGE. I connected the TANK inlet to the fuel line on the vapor separator, and the PURGE line I teed into the PCV hose. I have a replacement vented cap - but still have strong gas smell in the cab.

Ran the truck this morning (overnight ~70 degrees) with 1/4 tank - and smelled like I took a swim in a puddle of 93 octane when I got home...

I may need to check/replace all of the lines on the tank - but is there anything else I'm missing?

I've seen reference to adding a vapor purge valve like this but not sure how it's to be connected to vacuum.

Any recommendations would be appreciated.

Thanks.
 

Users who are viewing this thread

Top Bottom