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Thread: Fuel sender gasket (100923) sealing issue

  1. #1
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    Fuel sender gasket (100923) sealing issue

    As the title suggests, I'm having difficulty getting a good seal on the top of my fuel sender.

    I have a new-ish fuel sender (from October 2007, p/n 110555). Not that 11 years old is new, but it still looks like the design of the one offered on the vendor pages (not the pump/sender combo ones though of course).

    It came with the gasket seal (p/n 100923) used for those senders (and what is listed as still used for the blanking cap seal when you go with the pump/sender combo).

    I can smell gas fumes from time to time while driving and they are more pronounced when it's hotter outside and the cooling fans have been running. I did the little test to see if I can spot the leak by taking everything out of the trunk, going for a short drive around the neighborhood and slamming on the brakes from around 20 mph to get the gas to slosh around. Sure enough, I can see some has seeped up on to the top of the sender. It's not pouring out of there, but enough that when the cooling fans get going, they blow back on it and the fumes find their way into the cabin.

    I have had the sender out a couple times to see about realigning the gasket and realized there is a small notch of plastic not still on my fuel sender. It corresponds to a little hole in the gasket, likely meant to help keep things aligned and to stop things from moving around. I don't know how or why that piece got sheered off, but it isn't there anymore.

    Fuel sender gasket sealing issue.jpg

    Does anyone have any advice or suggestions on what to do with this to get it to seal completely? Or are my efforts in vain and I'm bound to just replace the sender with one that still has the little plastic notch in place? I don't see any gaskets offered that don't have that corresponding hole.


    Sept. 81, auto, black interior

  2. #2
    Administrator Ron's Avatar
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    As long as the seal is still soft (and the piece that broke off, or something else, has not damaged it), I don't see why you couldn't align the notches by eye and retest it... Orientation is not that critical and there's nothing that might twist it really.
    New gasket at worse, imo.

    I'd guess the broke piece was partially under the gasket and/or in the tank now...

  3. #3
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    Lining up the holes is what I think/thought would work too. I wasn't convinced that fuel wouldn't come up "through" that hole though. Technically, there is gasket material between the hole and the edge of the fuel sender, but not a lot in a couple of spots, specifically on that inside edge. Good call on the rubber still being soft though. It may very well not still be. Might be swollen though a little, which likely isn't going to help. A new gasket for <$10 isn't an expensive experiment, thankfully.


    Sept. 81, auto, black interior

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    Administrator Ron's Avatar
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    Quote Originally Posted by Jonathan View Post
    Technically, there is gasket material between the hole and the edge of the fuel sender, but not a lot in a couple of spots, specifically on that inside edge.
    Yeah...but the missing/broke tab wouldn't change the sealing surface area...

    Can't go wrong with a new gasket.

    Just hit me- Since you said, "...some has seeped up on to the top of the sender", I'd suggest making sure it isn't coming from around the wire terminals...

  5. #5
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    To get a good seal you must crank on that large plastic nut. To do that you need a large pair of channel locks. On my sending unit (an original type) I had seepage coming out the rivets holding the brass terminals for the electrical connections so I put some blobs of silicone over the rivets. Make sure the hose coming out of the bottom of the charcoal canister in the left, rear pontoon is not plugged up. Mine was plugged up with some kind of insect debris. Finally, the gas cap wasn't sealing well, the rubber was very hard. Probably because of all the Ethanol in the stuff they sell around here that they call gasoline. I had to get a new gas cap. Don't fill the tank right up to the top especially in hot weather.
    David Teitelbaum

  6. #6
    DMC Midwest - 815.459.6439 DMCMW Dave's Avatar
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    Quote Originally Posted by Jonathan View Post
    As the title suggests, I'm having difficulty getting a good seal on the top of my fuel sender.

    I have a new-ish fuel sender (from October 2007, p/n 110555). Not that 11 years old is new, but it still looks like the design of the one offered on the vendor pages (not the pump/sender combo ones though of course).

    It came with the gasket seal (p/n 100923) used for those senders (and what is listed as still used for the blanking cap seal when you go with the pump/sender combo).

    - - - -

    Does anyone have any advice or suggestions on what to do with this to get it to seal completely? Or are my efforts in vain and I'm bound to just replace the sender with one that still has the little plastic notch in place? I don't see any gaskets offered that don't have that corresponding hole.
    Does the gasket fit snugly around the body of the sender? If it seems "too big", it is. Over time, especially if you take them out a time or two, the gasket tends to swell up. If you leave it out of the car for a few days, it will shrink back to size. Then install it trying to line up the notch, but mostly trying to keep the sender centered in the hole in the tank while you tighten the plastic ring.

    Other things that can cause fuel smells on a hot day - look for a loose/cracked hose up near the filler neck and rollover valve, we've seen those crack or fail in some way. Sounds like you still have the original design pump, make sure it's still tight on the tank.
    Dave S
    DMC Midwest - retired but helping
    Greenville SC

  7. #7
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    Having the same probem here. Sending unit says delorean.com and gasket is fresh from.dmch but still leaks.

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    Administrator Ron's Avatar
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  9. #9
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    I'll see if I can get some photos to show you, but I think some of the sealing surface on the plastic tank side got scuffed by that missing plastic notch piece. I am guessing it got turned from the outside by trying to reef on the threaded ring too hard and then after the plastic chunk came off (agreed, that it's probably in the tank somewhere by now) it gouged the top of the sender hole. Maybe the inside edges a little too. I'll have to look closer to see what I may need to do to get it smooth again, or if there is too much material missing, how creative I'd need to get with some sealing goop.

    Dave S.... it was snug the last time I had it out. Enough so that you need to be pretty specific about it getting installed straight as when it's on even a slight angle, it just won't push down. So snug, yes, maybe swollen too a little. I'll take it out and leave it out as you suggested to see if that helps also.

    I have noticed that the very end of the wiring cable coming out of the top (from the end of the tab marked with DeLorean.com) sticks out just a little too far and inhibits you from getting the ring on nice and centred. You have to kind of force it over and then realign to make sure it is straight. I'm not sure if I'm describing that well, might take a picture of that too to show you what I mean.

    Ron... I don't think it is coming up the wiring as it seems to be seeping out from the threads and then up on to the flat top portion.


    Sept. 81, auto, black interior

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