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Fuel leak. Need to pick some brains.

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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Aintezbeincheesy
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Year and Model: 1994 850T
Location: Thornton, CO
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Re: Fuel leak. Need to pick some brains.

Post by Aintezbeincheesy »

tryingbe wrote: 27 Aug 2017, 12:50
Aintezbeincheesy wrote: 26 Aug 2017, 18:02
tryingbe wrote: 26 Aug 2017, 17:46 Remove the fuel pump bypass plate and see where the fuel is coming from.
If that's the plate over the fuel pump in the trunk I can't really get eyes on anything other than the fuel pump itself. I'm considering picking up a borescope for my phone expressly to be able to see what's going on there.
Did you take the plate off and found nothing leaking/wet?
As stated in the initial post, I removed the plate to find a pool of fuel around the fuel pump. I've cleaned it up since then, and the tank levels have dropped enough to where I'm not getting a pool anymore, for the moment anyways. I've already ordered the gasket since its a cheap and easy thing to cross off the list. If I find any more fuel on top of the tank I'm definitely going to throw some money at the hoses.

PeteB
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Post by PeteB »

I filled up and it dripped at the gas station, drove 1-2 miles home and it only dripped
slightly in the driveway. Added half a gallon and it was wet around the fuel pump - I
had replaced the fuel pump in the winter and was not able to fully tighten the ring,
tightened it about half a turn more and no more leak. Had to add another gallon or so
and then it dripped a lot from the hose - the hose was split.
Last edited by PeteB on 27 Aug 2017, 15:25, edited 1 time in total.

Aintezbeincheesy
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Post by Aintezbeincheesy »

jimmy57 wrote: 27 Aug 2017, 11:59 Does it only leak when filled or leak until it gets down to some level?
Sender/pump seal is a full tank leak. SOme hoses can leak due to syphoning effect but will leak until it gets to 1/4 tank.
If it only leaks when runiing and quits when engine is off then it is fuel supply line leak.
Then there is the recall for heat shield attachment points on tank breaking that affects some 850's.
It seems to only leak when the tank is full. It's dropped to about 15 gallons and it seems to have stopped pooling under the car.

Aintezbeincheesy
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Location: Thornton, CO
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Post by Aintezbeincheesy »

For now ive ordered the fuel pump gasket. I'll keep you guys posted. Really appreciate all the responses!

PeteB
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Post by PeteB »

This thread helped and I added a bit more to it - pictures of the long and short hoses:
viewtopic.php?f=1&t=54739&p=446934#p446934

Ozark Lee
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Post by Ozark Lee »

There is a recall on the fuel tanks due to cracks that occur around the heat shield. Check your local dealership with the VIN to see if your tank was ever changed. I'm not sure if there is an expiration date on the recall or not but they changed mine on the '94, at no charge, about 5 years ago.

...Lee
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
Previous:
1999 V70XC - Nautic Blue - Totaled while parked.
1999 V70XC - RIP - Wrecked Parts Car.
1998 S70 T5
1996 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

Aintezbeincheesy
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Post by Aintezbeincheesy »

Ozark Lee wrote: 27 Aug 2017, 20:15 There is a recall on the fuel tanks due to cracks that occur around the heat shield. Check your local dealership with the VIN to see if your tank was ever changed. I'm not sure if there is an expiration date on the recall or not but they changed mine on the '94, at no charge, about 5 years ago.

...Lee
Do you think it'd come out with enough force to pool around the fuel pump though?

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erikv11
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Post by erikv11 »

Yes these are all possible causes, even the heat shield issue, you need to check and try to hunt it down. It can leak somewhere else then run over/down to the pump, etc. I would replace the gasket (make sure it seats properly!), leave the cover off, go to the gas station and fill it up. Turn on the key and see if it still leaks - if you can, look right at the pump and have someone else start the car. Or turn it to position 2 so the fuel pump engages and head right back there before starting it, then start it and return to watch while it idles. Does it still leak? Can you tell where it starts from?

Also is the wiring seal still intact? You have to go through each one of the things suggested so far. The order of commonplace seems to be something like gasket, hoses, heat shield or fuel neck, wiring sealant (did I forget any?).
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

PeteB
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Post by PeteB »

You can look up by VIN to find out if the tank recall was done on your car,
ours had it done. I thought that leaked at a much lower level 3/4 maybe?

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