Gas Cap Whoosh

I don't have a T, however, that does not sound normal. My 3.2 coupes don't do that

 

1. Stuck rollover valve.

2. Collapsed filler neck due to excessive pressure buildup in the gas tank.

3. Clogged charcoal vapor filter. The charcoal filter is recommended to be replaced at about 50,000 miles according to the owner's manual, but this part is no longer available.

 

Factory...

 

+1: Roll over valve.
Vapor filter can be rebuilt/fabricated by a good mechanic/welder.

DavidJ

 

Hi

My 3.2 has started doing this, where is this rollover valve on a 3.2.

Cheers

Neil.

 

Mine does it depending on temp change. 5 years and 20K miles it has been doing it. Modern cars can do it too. 1987 3.2

 

You should have a pressure release upon unscrewing the gas cap as far as I am aware.

The fuel system is pressurised. If you don't, then you probably have a leak in the system or a failed pressure vessel. Have no idea if that applies to earlier cars, but certainly my T didn't have any pressure and I had a fuel smell..... fixed the leak and the system is now pressurised. The specialist diagnosed the problem initially by the lack of back pressure at the cap.

 

My T coupe has always done this and I have experienced no problems with the car.

 

I believe they are designed to take a certain level of pressure. I have also heard of issues of too much pressure causing problems lately. I don't have details. Sorry to muddy the water.

 

[+1QUOTE=B11ocx;143573993]You should have a pressure release upon unscrewing the gas cap as far as I am aware.

The fuel system is pressurised. If you don't, then you probably have a leak in the system or a failed pressure vessel. Have no idea if that applies to earlier cars, but certainly my T didn't have any pressure and I had a fuel smell..... fixed the leak and the system is now pressurised. The specialist diagnosed the problem initially by the lack of back pressure at the cap.[/QUOTE]

 

My 85 QV does this. A large whoosh sound when undoing the gas cap. My newer vehicles also do this.

And, as part of the emissions testing, here in Texas, they actually screw on a test cap to determine if your fuel system holds pressure. Note - This is only required for cars younger than 25 years old.

sid

 

Howie,

Are you having problems at the gas pump? By problems, I mean - constant shutting off of fuel flow. Excessive pressure can collapse your fuel filler hose - causing the backwash which triggers the shut off in the nozzle.. Also, make sure that the fuel cell isn't getting sucked in (as in - - imploding!!!)

Unfortunately, I speak from experience !

Cheers mate,

Hank

 

I've always had that super loud swoosh every time...last 3,000 miles.

 

+1

 

Normal with the K-Jet cars - apparently for the T too; the tanks are slightly pressurised. It also indicates that your system is gas tight.

 

I've had many cars of mine do that and they never suffered any ill effects from it. My cars did this based on temperature and altitude variations. Going from cold winters straight into hot summers and altitudes varying fro sea level to 3,000-4,000 feet. It won't hurt the car.

 

Hi folks,

Under normal circumstances, the fact that - - "they have never suffered any ill effects from it", would be 100% applicable and true.

In my case, the suction "woosh" at the gas cap inlet, accompanied by continual gas pump nozzle shut off while refilling - - and that nasty whining of my totally confused fuel pumps, certainly got my attention - - "oh ****, somethings' wrong here".

Eugenio found it all, corrected all the F-ups, and the Court agreed. Now, it's all just a part of Rachel's history.

Cheers, Hank

 

Air going out or in?

 

Air going out would be normal as there is a pressure build while the engine runs. When you unscrew the cap slightly you can feel gas-smelling air going out, the cap will get pushed into your hand when it comes off.
Air going in would be a problem as it will potentially lead to some hoses collapsing due to the depressurised condition of the system. While you unscrew the cap, you'd hear air being sucked into the tank, the cap would get pulled onto the neck and will be harder to take off at the end of the thread.

 

What were the specific F-ups (sounds like an F-Chat subgroup) were they?

I've had it happen only once on my 77 carb GT/4 after a long time sitting in traffic on a hot sunny day.

 

My "whooshes" always sucked when I opened the gas cap. They never blew.