760 V6 sedan (1988) fuel tank leak - How do I fix this?

[Duong Nguyen]

I have a leak at the plastic ring on the top of the fuel tank, where
the fuel pipes and fuel sending unit are connected. This ring is
probably the only thing holding the fuel tank lid in place. The rate
of leakage is about one drop in ~5 seconds when the car is on an
upward incline with a full enough tank and none otherwise. The
diameter of this plastic thingy is about 6" (15cm.) making it
impossible to remove with an oil filter strap wrench and my hands are
certainly not strong enough. Even the fuel sending unit connections
looks hard to remove. There seems to be no connector, only three wires
going into a plastic button that is nearly flush with the lid. My
question is what do I expect to see once I have managed to remove this
stubborn lid (a rubber gasket of some type may be?) and how to fix the
damned thing. Is a leak at this location dangerous? or can I make do
with simply not filling the tank? Is this tank set up interchangeable
with a same age sedan 740?

 

[Peter Milnes]

There is a special tool available to undo the retainer or you can make one
fairly easily. Once you have the retainer off then it is a simple matter to
replace the gasket and your leak will be gone.

Cheers, Peter.

: I have a leak at the plastic ring on the top of the fuel tank, where
: the fuel pipes and fuel sending unit are connected. This ring is
: probably the only thing holding the fuel tank lid in place. The rate
: of leakage is about one drop in ~5 seconds when the car is on an
: upward incline with a full enough tank and none otherwise. The
: diameter of this plastic thingy is about 6" (15cm.) making it
: impossible to remove with an oil filter strap wrench and my hands are
: certainly not strong enough. Even the fuel sending unit connections
: looks hard to remove. There seems to be no connector, only three wires
: going into a plastic button that is nearly flush with the lid. My
: question is what do I expect to see once I have managed to remove this
: stubborn lid (a rubber gasket of some type may be?) and how to fix the
: damned thing. Is a leak at this location dangerous? or can I make do
: with simply not filling the tank? Is this tank set up interchangeable
: with a same age sedan 740?

 

[Mike F]

I have a leak at the plastic ring on the top of the fuel tank, where
the fuel pipes and fuel sending unit are connected. This ring is
probably the only thing holding the fuel tank lid in place. The rate
of leakage is about one drop in ~5 seconds when the car is on an
upward incline with a full enough tank and none otherwise. The
diameter of this plastic thingy is about 6" (15cm.) making it
impossible to remove with an oil filter strap wrench and my hands are
certainly not strong enough. Even the fuel sending unit connections
looks hard to remove. There seems to be no connector, only three wires
going into a plastic button that is nearly flush with the lid. My
question is what do I expect to see once I have managed to remove this
stubborn lid (a rubber gasket of some type may be?) and how to fix the
damned thing. Is a leak at this location dangerous? or can I make do
with simply not filling the tank? Is this tank set up interchangeable
with a same age sedan 740?

There was a recall on these cars just for that reason. See if your car
qualifies. The recall involved making sure that "nut" was torqued
properly and installing a large hose clamp around it to lock it in
place. There's just a rubber seal between the sender and tank that
would need to be replaced if the recall doesn't apply. If you follow
those wires you can see a connector about 2 feet away.

740 (and 760 wagon) tanks of that vintage are smaller and not
interchangeable.

Any fuel leak is potentially dangerous.

If you do tackle this job yourself, do it with the tank down around 1/4
full.

 

[Duong Nguyen]

There was a recall on these cars just for that reason. See if your car
qualifies. The recall involved making sure that "nut" was torqued
properly and installing a large hose clamp around it to lock it in
place. There's just a rubber seal between the sender and tank that
would need to be replaced if the recall doesn't apply. If you follow
those wires you can see a connector about 2 feet away.

740 (and 760 wagon) tanks of that vintage are smaller and not
interchangeable.

Any fuel leak is potentially dangerous.

If you do tackle this job yourself, do it with the tank down around 1/4
full.

Thanks for answering my question. I really do want to fix this one
properly.
Do you have any more info on this recall or how to get more info on
this recall. The only relevant info I could find so far is this "TSB
38112 OCT 92 Tank Sending Unit - Replacement For Tanks W/Metal
Flange." Is this what you referred to in your message?

What is the reason the tank should be down around 1/4 full? My thought
is that the level only need to be below that of the plastic ring. Is
this the 1/4 full level?

 

[Mike F]

Thanks for answering my question. I really do want to fix this one
properly.
Do you have any more info on this recall or how to get more info on
this recall. The only relevant info I could find so far is this "TSB
38112 OCT 92 Tank Sending Unit - Replacement For Tanks W/Metal
Flange." Is this what you referred to in your message?

What is the reason the tank should be down around 1/4 full? My thought
is that the level only need to be below that of the plastic ring. Is
this the 1/4 full level?

No, your tank won't have a metal ring. You'll have to see a dealer
regarding the recall. All that's really necessary is to have the tank
below the level of the bottom of the ring, but lower is better. Then
there's less fuel dripping from the sender when it's pulled out.

 

[alpedjo]

I made a big mistake

I have Volvo 760 gle 2.4 diesel. Yesterday my brother took 2 litres of petrol and poured into my car. I have not started it up, because I do not know how to remove petrol from fuel tank. Please smbd help me...

Sorry for my bad English, Alpedjo