Fuels smell in cabin

[FastTex]

I know I have some small fuel tank leak but I have noticed in my last few trips to the hangar a smell of fuel when I open the cabin. I have not been flying for about one month and here (SC) the temperature has been very hot (90F++). Also, for the first time, I bought one of those ASA CO sensor and it show dark in the center but I think it's badly impacted by the heat therefore unreliable. I'm going to change with the Quantum Eye I have been using for many years (AircraftSpruce).

Any thoughts and/or things I should check or be concerned? I cannot see anything when looking inside...

Thanks!

[Bartman]

Get in the back seat and lift the carpet. Look in the corner for blue stain and evidence of leak. I had mine redone by Edison at Wetwingologist KFXE about 8 years ago, but before the reseal it only leaked and had fuel odor if I had more than about 12 gal in the left tank. 

[FastTex]

2 minutes ago, Bartman said:

Get in the back seat and lift the carpet. Look in the corner for blue stain and evidence of leak. I had mine redone by Edison at Wetwingologist KFXE about 8 years ago, but before the reseal it only leaked and had fuel odor if I had more than about 12 gal in the left tank. 

Thanks I will definitely check it tomorrow. Speaking of tanks...I have not searched but I'm sure there are lots of posts related. What's the best way to solve this issue for good (or long term)?

[Bartman]

Depends on the source. Might be as simple as fuel gauge sender gasket seeping. Might get by with a patch, might need full reseal or even bladder installation. But reseal vs bladder is kinda like religious belief, just like many other common issues. I chose reseal because it patching twice did not work. 

[N201MKTurbo]

18 minutes ago, FastTex said:

 here (SC) the temperature has been very hot (90F++)

It doesn't get that cold at night! 

[carusoam]

Common solutions to your challenges...

1) fuel level sensor seals get old and leak.  Easy to identify. If you are lucky, change these low cost seals....

2) Search For carbon monoxide sensor.  The goofy chemical eyes aren't modern enough technology.  A real sensor like sensorcon is worth the coin...  Many MSers have gone to using this portable device...  Go Dan! @DanM20C

3) fuel leaks come in a variety from leaky rivets, to leaky seams, to aged sealant that is falling off...

4) there are ways to determine the location of tough leaks... start with the easy ways first.   Post a pic of any blue stains... in the cabin? Remove the lower wall coverings inside the cabin.  This is where the fuel senders hide.

PP thoughts only, not a mechanic...

Best regards,

-a-

[MyNameIsNobody]

Fuel (not burned) has nothing to do with a CO sensor...Just sayin’

[MyNameIsNobody]

If you have fuel smell in cabin you likely have leaks in your fuel senders.  Fix ‘em, or open the door and air it out before you fly.

[Johnnybgoode]

6 hours ago, MyNameIsNobody said:

If you have fuel smell in cabin you likely have leaks in your fuel senders.  Fix ‘em.

Fixed it for you.

[jaylw314]

11 hours ago, MyNameIsNobody said:

Fuel (not burned) has nothing to do with a CO sensor...Just sayin’

CO does have no smell, but the conditions that produce it (rich mixture and exhaust in cabin) does produce a fuel smell, so it's still a possibility, and a potential far more dangerous one than a fuel leak.

[MyNameIsNobody]

1 hour ago, jaylw314 said:

CO does have no smell, but the conditions that produce it (rich mixture and exhaust in cabin) does produce a fuel smell, so it's still a possibility, and a potential far more dangerous one than a fuel leak.

Thought poster was talking about a fuel smell in cabin BEFORE engine start.  My bad.  Fuel smell in cabin with blue stains on rear co-pilot/pilot sides are classic indicators of seal failure on fuel senders.  I KNOW from personal experience.  Carry on....

[jaylw314]

2 hours ago, MyNameIsNobody said:

Thought poster was talking about a fuel smell in cabin BEFORE engine start.  My bad.  Fuel smell in cabin with blue stains on rear co-pilot/pilot sides are classic indicators of seal failure on fuel senders.  I KNOW from personal experience.  Carry on....

No, you're right, it does sound like @FastTex was describing fuel smell when opening the cabin door, but I figured he must have been talking about while engine was running otherwise he wouldn't be telling us about a CO monitor...

[FastTex]

I called CO monitor the little ASA card. And, yes no engine started but the smell just opening the cabin. I finally flew today and vented the cabin first. I need to ask my A&P to check the fuel senders.

Is it a big deal to inspect and fix them? Any idea how long it should take?

I also notice another leak on the left wing while I was doing my post flight cleaning. I might need to start thinking about sealing the tanks and wondering what's the best "long-term" solution. 

[carusoam]

Fast,

All you need is a pair of hands to run through the basics...  a screw driver to get to the next level of problem solving...

It is best to do a lot of the searching and finding before paying a mechanic by the hour.... 

Best regards,

-a-

[Immelman]

Pull the under-wing inspection panels just under each leading edge, closest to fuselage. Inspect for fuel running down the forward spar. This is very low effort and if there is a bad leak, it can go into the cabin this way.

If that does not yield anything, pull your lower interior side panels on each side to expose the fuel line/sender coming from each tank.

Those are good starting points.

[Don Heene]

I would check the fuel sender inside the cabin both wings.  Remove the side panels to check it out.  Here's a pic of mine.  I had a fuel smell in the cabin.  It's an easy fix, just have the fuel below this fuel sender gasket before removing.  There's I think 5 screws to remove.  Do it the right way clean up the stain and replace with a new one.  You could try tightening up the screws to see if that works.  

[DonMuncy]

If you take the senders out, be careful to replace the washer/spacers exactly the same way they were. The sender body (on later models, at least) are insulated from the tank. 

[FastTex]

thanks for the recommendations. Awesome pictures. Thanks!

Edited July 22, 2018 by FastTex

[carusoam]

Way to go DH!

Great Pics!

Another thing to look for while in there....

There is a small rubber connector to connect the fuel line out of the tank with the fuel line to the engine...

It is hiding in the shadow of DH’s pic... it’s there IF you look closely...

Back in the day... that rubber tube was not very fuel resistant....

Check it for how it looks... cracked and brittle? Could be getting ready to leak...

If Original to the plane... swap it out for some new fuel resistant ones...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Prior owner]

I agree that it is always best to simply pull the side panels and have a look- here’s a leaking sending unit. 

[RobertGary1]

Kind of strange that only a few little screws keep the content of the tank from gushing into the cockpit in flight. Of course the entire engine is attached to the airplane by a few very small bolts holding the mount to the firewall as well.

 

-Robert

[jaylw314]

26 minutes ago, RobertGary1 said:

Kind of strange that only a few little screws keep the content of the tank from gushing into the cockpit in flight. Of course the entire engine is attached to the airplane by a few very small bolts holding the mount to the firewall as well.

 

-Robert

Well, there's also a fair amount of fuel tank sealant too--I wouldn't want that stuff sticking my hands to my face!

[FastTex]

I guess it's time to consider a permanent solution. I have occasional leaks on both sides and now the left one is dripping fuel even after applying the sealant. Bladders time?

I do not feel comfortable going anywhere like this. Not sure how many of you run into this issue and feel ok with just the sealant...I had my gauges and senders just overhauled.

 

Edited August 12, 2018 by FastTex

[Prior owner]

Hmmm... the sealant should be applied to the interior of the tank only, correct? Never seen an attempt the seal the leak from the outside...

the rubber fuel line connector on mine was hard as a rock.  Per LASAR, Mooney specifies Mil H6000 rubber line as a replacement...which I think is below the standard of what is available today.

Edited August 13, 2018 by PilotCoyote

[FastTex]

1 hour ago, PilotCoyote said:

Hmmm... the sealant should be applied to the interior of the tank only, correct? Never seen an attempt the seal the leak from the outside...

the rubber fuel line connector on mine was hard as a rock.  Per LASAR, Mooney specifies Mil H6000 rubber line as a replacement...which I think is below the standard of what is available today.

My mechanic replaced both lines too...I just think sealant it's too sensitive and soon or later it will brake down again...not happy about the huge expense but want to find a permanent solution. Not sure how many Mooneys are flying regularly with just sealant for long time...