Fuel Leak-uh oh
 

Hi Everyone,

I've sprung a leak on my '85.

Its coming from the back of the rear passenger side near the fuel pumps.

I recently replaced the gasket on the sending unit and am wondering if the return hose fitting could be leaking? I cant see where it goes.

I checked the fuel pumps.. all high and dry there.

Are there any visible areas I can check without dropping the tank? If I have to go that route, I'm gonna send the car off to Pete as I dont have the time or room to do that.

TIA

This happened after I filled the tank to full. I parked the car and saw a slob but steady drip of gas. I jacked the car up on the right rear and loosened the gas gap and the leak stopped.

I've found two cars where stereo installs compromised top area of fuel tank. Leaked only when full.

could be vent hose for letting air out of tank when filling.. goes from tank spout through the chassis then into top of tank. Its a royal pain to replace, get your zen right before starting.

I've got a stock sound system (save for head unit).. so, is not that.

Does this reconnect back on top of the fuel sending unit? If so, I think thats the culprit..

No, that is the return line from the engine. Those can leak too..

No, here: http://www.autoatlanta.com/porsche-p...section=201-00

#12

Can you post any pictures that show where it is leaking? As high up as you can see with a flashlight.
(I assume have looked and it is not actually leaking at the fuel level sender/return line area?) You said you just replaced that gasket, but maybe it didn't seat correctly?
That should only be a problem if full.
Jason

ok

Thank you for sending this. Looks like a PITA to extract. clearly a tank out deal.

Lift the carpet and the right side padding from the luggage boot. There's access to the top of the tank where the sender drops in, and for the short hose section where the steel fuel return line (from the fuel pressure regulator in the engine bay) connects to the return flow nipple on the sending unit. That hose seldom leaks but should be on everyone's replacement schedule when renewing pressure hoses. ** You had this disconnected when you replaced the sender seal, so would be a good suspect. If the tank is full, this line will have liquid in it even with the engine off.

There's a ring seal where the tank sender seals to the tank itself. That large ring with the ribs on it unscrews from the tank nozzle after you disconnect wring and that tank return hose. This ring has liquid contact when the tank is close to full. ** This is the seal you say you recently replaced. If your leak is concurrent with "just filled the tank", I'd be looking at that seal again as a first probable cause, along with the return line connector hose there. That ring must be tightened correctly and the seal itself can't be distorted or it will leak. Stan (mrmerlin) will remind us to use Dow-Corning DC111 to lubricate that seal, after carefully cleaning and inspecting the sealing surfaces on the threaded tank nozzle flange and the inside seat in the threaded ring. DO NOT HAMMER ON THE RING trying to get it tighter. You'll gall and rip at the seal surfaces if you try to over-tighten the ring. Make a tool for the ring with a 6" ABS drain pipe connector and some TEK screws so you can remove and install the ring with even pressure.


More:

There's a soft "balancing" hose that connects to the tank near the filler neck, and also to the main part of the tank somewhat near the sender. That fabric braid-covered hose passes through a hole in the body above the tank on the right side, to the rear of the filler neck in the wheelwell. These hoses often get cut in haste when removing the fuel tank, a mistake when you discover the replacement costs. It looks like a common vent hose except for a critical bend at the filler neck end. This hose will have liquid in it only when the tank is close to full. It's purpose is to let air from the otherwise-stranded top of the main section pass to the filler neck. When blocked or kinked, the tank will only fill to about 3/4.

From the bottom, you'll want to remove the fuel pump and filter cover if you find fuel dripping there.


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Work outside, away from the house and garage. Keep a charged garden hose handy, and have a couple fire extinguishers handy just in case something goes wrong. No Sparks. Drain fuel from the tank if you can before you start to minimize the risk of liquid coming out when you open or disconnect something.

Thanks for the comments and help everyone.. I had some time to dig deeper tonight, and the leak is coming from way up on top of the tank and looks to be either a crack, cracked hose, or fitting.

When the car is moved and even on the slightest incline
https://cimg9.ibsrv.net/gimg/rennlis...1ebc43c093.jpg
, I have a significant leak (see pic below)

I'm having it towed to Pete tomorrow... stay tuned..........

In the mean time, siphon out a couple gallons of gas to stop the dripping.

+1 ASAP

When I have replaced that particular seal, I have always had to "snap" the sender unit back down into place before attempting to screw the large ring back on. If it doesn't snap back down into place, the large ring can not place enough pressure to seal the sender unit and the resultant gap will leak fuel.

To remedy, unscrew the large plastic ring, move it up out of the way a bit and push down hard on the top of the sender unit, it should snap into place. Replace and tighten the large plastic ring.

Hi Everyone,

It's definitely not the sender. I traced the leak all the way up towards the top of the tank/filler neck. I'm suspecting the tank is either:

-cracked at top
-gasket on filler neck is worn
-t-fitting/hoses at top are shot.

In any event, I sent the car over to Pete last Saturday.. I'll keep you posted on his diagnosis... Here are some pics of her being loaded up.

Even on the flatbed, I love the stance!
https://cimg4.ibsrv.net/gimg/rennlis...0ad5ed294c.jpg
https://cimg8.ibsrv.net/gimg/rennlis...3a71a6f394.jpg

Based upon your pictures, I would gamble that you have a crack on the top of the tank.
I say this because it seems to be a weak spot.
This is shown in Dwayne's thread, below. And, I just dropped a tank last week out of an '85 to clean it and there was a crack in the exact same spot. Not all the way through yet, but same spot.
https://rennlist.com/forums/928-foru...re-w-pics.html
However, your leak looks to be on the side where the vent fittings go into the tank, so that may be it as well.
Let us know what your guy finds, and take pics to post!
-Jason