Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

Fuel Leak-uh oh

 
Old 07-12-2019, 11:32 AM
  #1  
997TTEQNY
Addict
Rennlist Member
Thread Starter
 
997TTEQNY's Avatar
 
Join Date: Jun 2017
Location: Long Island, NY-East End
Posts: 241
Likes: 0
Received 3 Likes on 3 Posts
Default 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.
997TTEQNY is offline  
Old 07-12-2019, 12:23 PM
  #2  
Landseer
Addict
Rennlist Member
 
Landseer's Avatar
 
Join Date: Sep 2007
Location: Frederick, Maryland
Posts: 11,326
Received 6 Likes on 4 Posts
Default

I've found two cars where stereo installs compromised top area of fuel tank. Leaked only when full.
Landseer is offline  
Old 07-12-2019, 12:41 PM
  #3  
drooman
Addict
Rennlist Member
 
drooman's Avatar
 
Join Date: Jun 2011
Location: CT and FL
Posts: 1,191
Received 28 Likes on 17 Posts
Default

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.

Last edited by drooman; 07-12-2019 at 01:45 PM.
drooman is offline  
Old 07-12-2019, 01:00 PM
  #4  
997TTEQNY
Addict
Rennlist Member
Thread Starter
 
997TTEQNY's Avatar
 
Join Date: Jun 2017
Location: Long Island, NY-East End
Posts: 241
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by Landseer View Post
I've found two cars where stereo installs compromised top area of fuel tank. Leaked only when full.
I've got a stock sound system (save for head unit).. so, is not that.

Originally Posted by drooman View Post
could be vent hose for letting air out of tank when filling.. goes from tank spout through the chassis then into top right side of tank. Its a royal pain to replace, get your zen right before starting.
Does this reconnect back on top of the fuel sending unit? If so, I think thats the culprit..
997TTEQNY is offline  
Old 07-12-2019, 01:47 PM
  #5  
drooman
Addict
Rennlist Member
 
drooman's Avatar
 
Join Date: Jun 2011
Location: CT and FL
Posts: 1,191
Received 28 Likes on 17 Posts
Default

Originally Posted by 997TTEQNY View Post


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..
drooman is offline  
Old 07-12-2019, 02:52 PM
  #6  
Speedtoys
Addict
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 9,935
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by 997TTEQNY View Post
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, here: http://www.autoatlanta.com/porsche-p...section=201-00

#12
Speedtoys is offline  
Old 07-12-2019, 03:04 PM
  #7  
Jason89s4
Addict
Rennlist Member
 
Join Date: Jan 2019
Location: Dallas
Posts: 227
Received 1 Like on 1 Post
Default

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
Jason89s4 is offline  
Old 07-12-2019, 03:43 PM
  #8  
997TTEQNY
Addict
Rennlist Member
Thread Starter
 
997TTEQNY's Avatar
 
Join Date: Jun 2017
Location: Long Island, NY-East End
Posts: 241
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by drooman View Post
No, that is the return line from the engine. Those can leak too..
ok

Originally Posted by Speedtoys View Post
Thank you for sending this. Looks like a PITA to extract. clearly a tank out deal.

Originally Posted by Jason89s4 View Post
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?

I'll snap a few pics later. Its not coming from the sending unit. High and dry there with a brand new gasket
That should only be a problem if full.
Jason
997TTEQNY is offline  
Old 07-12-2019, 04:49 PM
  #9  
dr bob
Chronic Tool Dropper
Lifetime Rennlist
Member
 
dr bob's Avatar
 
Join Date: Oct 2001
Location: Bend, Oregon
Posts: 18,021
Received 13 Likes on 12 Posts
Default

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.


-----

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.
dr bob is offline  
Old 07-12-2019, 10:36 PM
  #10  
997TTEQNY
Addict
Rennlist Member
Thread Starter
 
997TTEQNY's Avatar
 
Join Date: Jun 2017
Location: Long Island, NY-East End
Posts: 241
Likes: 0
Received 3 Likes on 3 Posts
Default

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

, I have a significant leak (see pic below)

I'm having it towed to Pete tomorrow... stay tuned..........
997TTEQNY is offline  
Old 07-13-2019, 09:51 AM
  #11  
Petza914
Addict
Rennlist Member
 
Petza914's Avatar
 
Join Date: Oct 2007
Location: Clemson, SC
Posts: 11,154
Received 59 Likes on 46 Posts
Default

In the mean time, siphon out a couple gallons of gas to stop the dripping.
Petza914 is offline  
Old 07-13-2019, 10:16 AM
  #12  
merchauser
Addict
Rennlist Member
 
Join Date: Jan 2017
Posts: 1,512
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Petza914 View Post
In the mean time, siphon out a couple gallons of gas to stop the dripping.
+1 ASAP
merchauser is online now  
Old 07-13-2019, 11:31 AM
  #13  
soontobered84
Addict
Rennlist Member
 
soontobered84's Avatar
 
Join Date: Mar 2002
Location: Texas
Posts: 5,031
Received 4 Likes on 4 Posts
Default

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.
soontobered84 is offline  
Old 07-16-2019, 02:18 PM
  #14  
997TTEQNY
Addict
Rennlist Member
Thread Starter
 
997TTEQNY's Avatar
 
Join Date: Jun 2017
Location: Long Island, NY-East End
Posts: 241
Likes: 0
Received 3 Likes on 3 Posts
Default

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!

997TTEQNY is offline  
Old 07-16-2019, 02:46 PM
  #15  
Jason89s4
Addict
Rennlist Member
 
Join Date: Jan 2019
Location: Dallas
Posts: 227
Received 1 Like on 1 Post
Default

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
Jason89s4 is offline  

Thread Tools
Search this Thread

Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: