[Peter B]

I agree that there would be comforting to know that this problem was often solved. If this isn't the case then that would be good to know too.



I'll see how it goes replacing the gasket.



The though has occurred to me that these old and buried rubber hoses may just reek of gas after being exposed to gas for so many years.

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[Paul W]

I read that the other day, but it references metal gas tanks that are different configurations from the 968 (which are plastic), or at least that's what I thought.

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[MB968]

Peter, as long as the hoses were made from the correct polymer, their age shouldn't mean a whole lot unless they've been exposed to excess heat or something that wasn't considered in the design. They are much more likely to fail at the fitting, or due to rubbing on another surface.



As far as the gas cap gasket, it is also cheap and easy to replace (like the one for the fuel level sender in the top of the tank). However, it seems unlikely that the gas cap gasket would lead to gas smell inside the car just due to where it is located.



If you decide to do the fuel level sender gasket and can't figure how to get the large cap off, contact me and I can help you with how to get it off. It is fairly easy with one of several different tools that might be in your garage.

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[jfrahm]

I just addressed a gas smell in my black car. I found a cracked fuel return line nipple (under the trunk carpet, under the fiberglass square, under the black cap) and the return line had also perished to the point that the hose clamp had fallen off. I replaced it with 3/8" fuel line and used a rope to chase the bad hose with good. I found I could not pull the new hose up from below but could easily pull it down from above. I needed to remove the flare fitting down below and cut off the crimp, and clamp on the new hose. The fuel filter was disconnected (and replaced) for access.



I also potted the cracked barb/nipple in JB Weld and it's all fixed, or seems to be. Before with the tank full I had gas on top of the fuel level sender cassette with the two barbs, and I could easily feel the return line barb was cracked loose.



-Joel.

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[MB968]

Joel, I had exactly the same issue at least I think we're talking about the same thing. One of the metal lines coming out of the top of the fuel level sender was no longer a leak free fit. Kind of looks like the pipe was swaged in the metal lid. It didn't appear to be welded/silver soldered. If my car sat for a while, the fuel would wick up through this small gap, and re-condense in the depression around the cap. After a day or so this area would have about 1/4" of gas sitting in it. Currently I only have a temporary patch. Had what I think is a butyl based material that I could pack around the pipe. Area has been dry now for weeks, and the only remaining smell seems to be in the carpet in the rear from years (probably) of having a pool of gas sitting below it. Since I thought my case was a one off, I started looking locally for the part, as it has been used on all 944/968s since mid year 95 or 96. Seeing that you've had the issue too, I think I will take mine off over the winter and put a permanent fix on it. Never used JB weld before, I assume it is an epoxy based material. Do you know if it will be a permanent fix?

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[Peter B]

Great inputs from everybody.



I just replaced the fuel sender gasket. I don't think this was it. After cleaning up the gas I spilled, it still smells the same there. I don't see gas pooling at the same location, but I'll take a close look.



I have noticed that the hose is so compressed the clamps don't go as tight as I'd like them. I am going to replace these because they are cheap.



The smell in my car seems to be coming more from down the end by the hoses off the fuel sender. I do like the idea of pulling the old house our and pulling a new one in. I think I need to keep following my nose. If this doesn't work, it's a process of elimination (which takes to long).

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[jfrahm]

I assumed that barb was brazed in, but I did not look closely, I just cleaned it up real good and JB-welded it. Yes, I feel it is a permanent repair, I have used JB Weld in the past to fix holes in magnesium motorcycle side covers, metal gas tanks, radiator necks, etc. Surface prep is important as is thorough mixing of the product and reasonably warm temperature of the work. I gave the work a scrub with 91% alcohol and a toothbrush (I used my girlfriend's) and wiped, then let it dry. I pushed extra epoxy under the curve of the barb, I am OK with some extra support there. Someone thought this leak can be caused by improper jacking technique causing the barb to contact the cover or something, I dunno about that but I'm happy to have a gusset there.



To chase that return line it was suggested to punch the hose end and thread in a thin rope, this is more or less what I did. I had some 1/16" coarse nylon twine-like material, I melted the end and pulled it to a sharp point to cram through the hose. If the hose gets stuck you need something strong. When installing pull the new hose down from the top (maybe 2' of 3/8 line) and make sure it goes straight into the provided channel. I actually used steel wire punched through and and attached to the old hose and then pulled the nylon twine in after that using the wire leader. This allowed me to drill and thread the nylon line onto the new hose on the bench. Naturally the drilled/punched part of the hose is cut off and discarded once it's in place. I have run a lot of cabling and chased a lot of cables, typing/taping one to the other so I am familiar with making snag-free and strong connections. I duct-taped the tie-on and made a nose cone for the hose with a small amount of tape. Overkill perhaps, but easy to deal with as I just cut off and discard any taped hose or knotted line so it's easy to undo.



You'll want to reuse the spiral hose protector and cut your hose short enough so it does not rub on the transmission. You also need an extra high quality hose clamp to replace the crimp on the hose down below. This is a low pressure return line. I pulled the fuel pump fuse (#34 on my car) with the car running to kill the line pressure. This reduces the gas shower but there is still a fair bit if you take the fuel filter off, or even just disconnect it.



I evaluated the fuel filter rubber lines and to my surprise mine are in great shape. I had some 5/16" hose handy and thought about rebuilding them, but saw no need. I guess it's cooler back there and the hose lives longer. It looks like my return line delaminated due to gas exposure at the cut end over time and even the rest of that hose was not in bad shape. I could see just replacing the delaminated end of that line with a 3/8" union and a stub of new line in a pinch or if you expected to be under the car doing more work (fuel filter, axle boots, rear shocks) at some point in the future and wanted to put off the undercar repair until then.



-Joel.

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[Paul W]

Joe: Good info!



I've done "JB Weld" type repairs before to the high pressure side of the fuel system, for other's info, here is a procedure, not specific to the 968, but it gives some tips and has pictures:



http://www.audipages.com/Tech_Articles/e...epari.html

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[flash]

fuel lines, like most rubber hoses, fail from the inside out. you cannot determine their condition by visual inspection. they do age out. that is why it is required that it has a manufacture date on it. remember that the fuel is running at a minimum of 53psi. that asks a lot from hose over time.



as an indicator, aircraft replacement interval is as little as 12 to 18 MONTHS



here is a decent article on fuel hose:



http://www.hotrod.com/techarticles/engin...ewall.html

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[Paul W]

Flash....I'm not going to pressurize my fuel system again until I replace every hose!!!!



LOL



;-)

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[flash]

funny - well, if you don't change them, all i can say is "don't complain about gas smell" when one leaks



i hate down time with cars. i spend less time repairing things because i proactively change them before they fail. i am then able to group things together, making the job more efficient, and a lot less expensive. i can't remember the last time i had to take a car to a shop to fix something that broke or wore out (besides tires). i am able to schedule these things, avoid the nasty tow truck drive, waiting, frustration, and above all else, having to deal with the wife yelling at me.



by the way, if a hose has a leak enough to smell gas, you are losing pressure, which means you are likely losing power, and nobody likes that

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[hot968]

Flash, you said losing pressure -likely loosing power. I had the fuel pump and fuel filter changed after the car sat for 8 years neglected. When I got it back it had less pick up on take off. Do u think my hoses maybe the problem and I should change them all around the gad system? thanks

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[flash]

i would pressure test the system to find out.

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[MB968]

If the pressure looks OK when you check it at the fuel rail, preferably under max. load conditions, then that means the pump has enough capacity to handle any loss from compromised hoses. If it is only smell, and not any real loss of fluid, then it is unlikely that the hoses are having any impact. After all, that same pump as far as I know is supporting the flow of s/c'd engines. At least I haven't seen any posts referring to having to change a pump. If that's the case, the stock pump's capacity is considerably more than needed.



Or, if you aren't getting the right pressure at the fuel rail, it could be the pump at fault, or the pressure regulator whose task is to keep the higher pressure that the pump is capable of regulated down to the proper pressure by bleeding off fuel (that returns to the tank). The fuel filter is also another culprit. But, I guess we digress.

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[flash]

actually, our pump is a bit marginal. it's the only one with as low of a volume as it is. not sure why they used it. i am maxxing it out right now. but yes, it is the same pump used in the SC kits.



i would still pressure test the system. it should hold 60psi without any leaks. with a pressure test, it will show you the leaks, without spraying fuel all over the place (once the lines are cleared)

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[Paul W]

I believe I fixed my fuel smell in the cabin yesterday by changing out the sending unit rubber gasket. It went something like this:

• It was an unseasonably hot day yesterday in Chicago, took the car out the garage and drove it about 20 minutes. No gas fumes initially. The fuel is "cold" and it had been sitting for 4 or 5 days, so no fuel wicked up to the gasket area.
  
  
• Parked it in the sun for an hour, came back, TOTAL fuel smell in the car. This is with the cover off on the fuel tank sending unit. Drive it a little bit, you can tell there is more fumes coming in the car.
  
  
• Stop at a store, do a "nose" test at the sending unit, can definitely smell it very strong right there, nothing "wet".
  
  
• Come home, change out the gasket, easy job.
  
  
• Drive the car around to "splash" the fuel in the tank, the level was about 2" below the neck that holds the sending unit.
  
  
• Parked it in the sun for about 20 minutes with the windows up, no smell of fuel at all. Did the smell test at the sending unit, nothing.
  
  
• Buttoned everything up and drove it last night. It did get dark, but I would normally smell fuel, just not nearly as strong at night, but NOTHING.
  
  
• Left the car in the garage with the windows up, this morning no fuel smell at all.
  
  
• Drove it around this morning in cooler weather, no fuel smell.
  
  

I'm going to say the jury is still out, but it's looking good. The old gasket definitely had a compression set, and the hose clamps could of used a little more tightening, but I think this might of proved what I saw at the gas station with the small bubbles coming out around the sending unit plastic cap when filling it....I believe it was venting through this connection.









The gasket actually sits on top of the plastic neck and is mounted on underside of the sending unit. There are vent holes for the fuel at the top right at the gasket location.









The little hose on the right in the picture above, just loops around to a "T" connection that goes into the tank (see pictures previously in this thread) to see tank pictures, and then it goes off to the left hand side of the car. The neck is about 2" high, so there is no way that water could wick back up into and into the tank. Forward (from back of car to front of car) in the image below is to the left, where forward in the image above it up.











You can see the vent holes, there are six? of them going around that the gasket half covers when in place.











New gasket installed, you can see how the holes get partially covered up. Gas is going to splash out of those holes, and if the gasket is compromised or taken a compression set over the years, it's going to vent the tank across it with the gas vapor:

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[Paul W]

Here is a comparison between the old and new gasket, the new gasket has a smaller inside diameter (ID) and smaller outside diameter (OD), new gasket on the right, old one on the left:







And here the old gasket sitting on top of the new gasket, you can see how the inside diameter is very much different, the old gasket took a compression set over the many years of service:







I did not get the cap as tight as it was when I started....here is the starting position of the cap:







I used a blunt chisel and hammer to loosen it, I'm sure there is a tool for this, but I don't have one. If you do this on a cold day, use a hair dryer or something to heat up the plastic so it won't be so brittle:







And here is the final position of the cover after I tightened it down, kept wacking it gently (if there is such a thing), I thought I over tightened it myself, but now that I look at the pictures, I see it is less tight.

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[Paul W]

The part number for the gasket is 944 201 327 00 and it's about $10.







Here is a picture of the backside of the cap:







Here is the whole unit, it's skewed, so when you take it out of the tank, it comes up about an inch, then you have to skew it to get it the rest of the way out. It is skewed towards the center of the tank.







And to recap my smell/fix:

• On hot days, I would get the fuel smell in the cabin. Using my nose, I could tell it was coming from the back of the car, near the little vents where the hatch glass is adjacent to the glass. Worse when the tank was full, not so bad when below 1/4 tank. Once the smell came in, it would come in driving down the road. Sniff test from the front vents with the AC on, no fuel smell, coming from the back.
  
  
• Disassembled fuel fill neck, inspected everything, could not find anything cut or ripped.
  
  
• By chance, assembled the fill neck wrong, filled the tank up, fuel spilled over the top of the tank and sat in a small pool around the sending unit cap (see pictures above in thread) and I could see small bubbles venting out when filling.
  
  
• This lead me to believe that it was the gasket, replaced it, and all is well for now.
  
  

Hopefully I won't have to edit this in the future!

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[Lear35A]

Well done. Well documented. Thanks, you've set a high standard. We all need to learn from this.

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[flash]

lol - if you send it all to me in a PDF, i can post it and pin it in the DIY area

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