mtnance

After a drive and I park in the garage, there is a medium smell of gas/exhaust fumes. Not extremely overwhelming, but an odor. After allowing a few hours and after the car has sat overnight in the garage, the smell isn't near as noticeable, but there is still a slight odor. The post I've read say that the 72 (350ci) fuel system is pressurized when driving and will find a place to vent if there is a place to vent. I've checked to see if gas drips in the carb, answer: no. Nothing drips on the floor either. Some post suggest the fuel vapor separator could be cracked. Some suggest fuel line to or from the tank has a very small pin hole and the gas evaps before it drips, while other talked about a charcoal canister (there isn't one on the car) Perhaps the gasket on the fuel cap is not sealing completely.

I don't know the routing of the lines yet however do you have to drop the gas tank to access the separator? Where is it?

I can place my nose at the front fender well of either side front end and no smell and it's a slight smell on the left rear, but the right right wheel well is most noticeable.

So, unless the tank itself has a extremely small pin hole, seems it would have to be either the gasket, lines or separator.

doorgunner

I had to replace the original rubber hoses in my '68 fuel system.....there were no drips, but the hoses were slightly weeping fuel when they became warm from engine heat.....I had to drop the tank because the hoses were stuck to the metal tubes/I didn't want to damage the tank trying to force the hoses aloose. The system also had a steel return line that was weeping from rust issues. I also replaced the top tank gasket that was dry and separating (which I couldn't see until I removed the fill ring. (The previous owner had replaced the main steel fuel line). After making those repairs the gas odor went away.

mtnance

So, you didn't replace a separator? I have read a lot on it and some suggest they crack at the inlet's. Reason I ask, if it's located in a "bad spot" and you need to drop the tank anyway,....there $50.

mtnance

I know I need to get the AIM. At Eckler's they offer the manual but they also have an "index". DO I need both?

Easy Mike

You definitely want the AIM. Until you know your way around the AIM, an index can be useful. It's a waste of money if you've been flipping AIM pages for a decade or two.

20mercury

Thought for you on AIM index, after flipping and flipping, the order of the AIM is not particularly intuitive for me anyway, maybe says something about my brain?? I decided to go through the whole AIM and make my own index. This works much better for me.

standswithabeer

had similar issue on my daughter's 83 bonneville. fuel line from tank to pump was new, canister hoses new, fuel lines new, no leaks found until i felt around/under the fuel pump right after running the car. turns out it leaked just a bit, but evaporated quickly making the source of the odor hard to trace.

GregS_72

The fuel tank separator is located near the left rear wheel well. I had the same fuel smell problem with my '72 car. When I pulled the body to start the resto, I noticed that one of the rubber hoses on the separator was cracked in half.


edit... oops, typo on location... fixed now

chvet73

The seperator on my 73 is on the left. Replaced it without dropping the tank. It was an uncomfortable hours job. But it can be done.

Go Vette Go

Had the same issue with my 76 several years ago. Could not find the culprit. I pulled into the garage one night after a cruise nite and the gas smell was strong!! Looked under the car and gas was dripping the muffler. Rubber hose between the fuel line and tank cracked.

I grabbed a towel to catch the gas while I dropped the muffler. Disconnected the fuel line at the pump and drained the line. Dropped the tank the next day and installed new hoses.

Vettesquid

Had similar problem on my 71. Replaced the gasket on the fuel cap and problem was solved.
May want to try that first. It is a low cost and easy fix.

Good luck

mtnance

I have a strong suspicion that's my problem. The smell isn't overpowering, but it's there after a drive. The fuel pump is new and there is no sign of leaks there, all "smells" are at the rear of the car. I really appreciate the pic. I may try to attempt the replacement of the lines without dropping the tank, but I have no problems in going that extra step(s). After the car has sat for an hour or two, the strongest odor comes from the left rear wheel area. I'll also replace the fuel cap gasket since that is an easy fix. One question though (until I can get my AIM), when dropping the tank, what do I need to watch for. I've done this on other cars many times, but I knew where everything was hooked up. For example , I'm not sure how the filler area is attached to the underside. I know there's a spill hose to drain fuel, but it looks like the large rubber "boot" just presses up like a large funnel on the underside.

GregS_72

I've never dropped the tank before with the body on, but here are a few more pics from my '72 that should help...

rubber gas tank filler neck seal just presses up to underside of body...


bolts at rear of frame holding tank straps down...


view of right side of tank; circles indicate cross member supporting front of tank and where it bolts to frame...

mtnance

Helps a lot, thanks. I read somewhere else that it's possible to replace those pesky lines coming from the separator without dropping but hard to access and I really don't mind dropping the tank to inspect it anyway. Just didn't want to pull something that shouldn't be pulled. Obviously, tank will be basically empty.

Aquitard

I'm having exact same symptoms on my 74 however it looks like somethings spraying in front passenger engine area as the hoses and suspension look "wet". But still the fume/gas smell my wife's been complaining about since I bought it last month...

mtnance

Update: I dropped the spare tire/holder and found that I have the original spare tire (Bonus I guess) and also was able to reach up and dislodge the tank sticker. It's pretty bad but you can make out a lot of it. The bad new is the fuel lines (though need replacing) isn't the (main) problem. I have a slight wetness to the touch on the anti-squeak pad that goes along the fuel tank support bar. Seeing as how the tank looked like it might be resting on pinholes that would/could break open if I move the tank, I left it alone. The tank need to be replaced. I'm going to get the tank "kit" and install.

GregS_72

I used the 'complete tank kit' from Eckler's for my resto. Couple of things I learned after the fact... the filler neck is not included in the kit, so either restore/reuse original or buy new. Also the kit did not include bolts to attach the separator, plus a new separator did not include the bolts either. Eventually found that 10-32 X 3/4" bolts fit.

mtnance

Thanks for the heads up. I checked the order and I have three boxes on it's way, 2 should arrive tomorrow. I can't tell right now, but not sure of the fuel hose size (rubber) that is required. They all seem to be the same. The plan is to attached everything new including extra long sections of the hose so they droop down and are already connected. Hopefully this will help trying to reach around once tank is in place.

The kit has the anti-squeak pads but I wonder if there is something else I can put there. Did you "add" to anything? It seems that's where the pin holes are, traps moisture at that pad. Not that I would have an issue next year, but down the line.

GregS_72

I used the anti-squeak pads that came with the kit... didn't 'add' or modify from there. Fuel hose doesn't come with the kit. I haven't looked into that yet. The kit does include the overflow hose from the filler neck seal though. Don't forget to reuse the plastic cover in the back as well, protects against puncture in a rear-end collision. The new mounting straps were a pain to fit/shape where they hook in.

mtnance

Okay,...I thought I would "preassemble" what I could and regarding the straps, have them in somewhat in the location before I raise the tank, using bungee cords to hold the ends in place. 10-4 on the guard.