LEAKING LPG!!!

[JimsMowing]

As the title suggests, my lpg is leaking!! Its been running fine up until a few days ago. Went to get some gas, put 40 litres in and drive up the road. As i start accelerating i notice it feels as though its not got any lpg. so i switch to petrol for the way home.

I get home have a poke and notice a wire has snapped. Transpires its the fuel level sending wire so now my lpg guage is working! But yesterday and today its been seaping gas after the engine has been running, more so today.

Then i get quite worried when i park up and as im walking away from my disco i hear wooooooosh. Its dumped a load of lpg out as a gas.

I seriously have no idea about lpg, but its my only car and need to get around as i use it for work.

The system i have is a BRC system, not sure on model number. I cant find anyone that deals with this system near me. I live in sevenoaks in kent. Do any of you guys have any experience with lpg, and if so do you know of any symptoms like this? If you do id love to hear from you.

Regards

Geoff.

[Skibum346]

In the immortal words of the hitch hikers guide to the galaxy...

DON'T PANIC

Firstly LPG is a far safer fuel than petrol as it is a volatile gas and is quickly dispersed in the air. Same volume of petrol would still be hanging around giving off potential fumes.

Don't know anything about your system but your description makes it sound like the tank safety valve has blown for some reason... maybe an electrical fault?

Check ou the LPGA website for registered fitters and get it down to one for an inspection.

In it's current state, assuming the tank has emptied, the system is basically safe.

[JimsMowing]

Thank you for your swift response! After it dumped the gas out i guessed it might have something to do with a valve of some sort.

I spoke with a fitter of different systems over the phone and he remarked about the size of the tanks. i said they are twin sill takes with a capaxity of 70 litres. He then asked me how much i could put in them. So i said sometimes it will fill up the max of 70 litres if i run it right down or other times i can only get 40 litres in.

I used to think this was because the pump was out, but now im thinking this happend to often to get to a pump out of gas.

So maybe the valve thing is something to do with this, sometimes it works sometimes it doesnt.  :?  Who knows...all i know is my disco drinks petrol even more so than a standard one as its mapped for the lpg!

[Skibum346]

Your tanks should have a cut off that prevents you from filling to max... for instance we have a 80litre tank that takes 60. This leaves room for the gas to expand when it's warm without over pressuring the system and blowing the safety valve.

Course... it could be your tanks are bigger than 70 but all they take is 70!

[Snake110]

:shock: from what youre saying it sounds like 2 problems
1 the aparant lack of fuel maywell be down to another
faulty connection shutting the gas flow off intermittantly

2 the venting is normal for an over filled tank
the given capacity of an lpg tank is the full (to the brim)
liquid capacity.
You can NEVER fill them to that level from a gas filling point
the nominal capacity for a full tank is 80% of its liquid capacity
so youre getting 70l in youre tanks must be 20% larger.
tempriture also has a bearing on this due to expansion
of the gas you will get more in on a cold day less on a hot day
venting can happen if you say fill early in the morning when its cold
and the weather warms up causing the gas to expand
and the tank pressure rises to the point where
the over pressure valve operates venting some gas untill
the pressure falls back to its working level
this can appear quite scary but is usualy
safer than it looks as long as the tank can vent to
atmosphire and not into the cabin
if the system was installed correctly it will
have a vent pipe routed to vent to open air

have a good look round the whole system
check ALL electrical connections for a good contact
and make sure any and all vent pipes are clear
and again check all pipework for tight connections
and damage .

most systems are quite simple once you see where
everything goes but if youre in doubt
take it to a good installer and have it checked out..

[thermidorthelobster]

If it vents again, you should be able to find out fairly easily where it's coming from, as any components around the leak will be cold where the gas is vapourising.

[Rossko]

If filling "to the stop" is sometimes half what you expect, there's two obvious thoughts.  One the tanks is not filling, or one is not emptying.

If one was filling but not emptying you'd probably splutter to a halt 100 miles earlier than you expected!  This isn't mentioned, sooo...

If one was not filling at all from the pump (sometimes) you'd have one tank with liquid and one with vapour only.  This can happen when the valve designed to stop filling at the 80% level sticks at the previous fill, and still prevents filling after the tank is empty.

Tip : the 80% valve is just like a ballcock, with a float on an arm.  Whack the suspect tank with a mallet and you may just hear the arm drop and bounce on the bottom.

The gauge on the dashboard connects to only one tank, which might be a 'good' one or the troublesome one.  So its reading might help interpret your symptoms.

In a correct installation, check valves should prevent cross-feeding between tanks via the supply pipes, so an empty one stays empty.    This sounds a possibile clue as it might tie up with the hesitation under acceleration ... vapour getting into the liquid feed pipe from the empty tank whilst the just-filled tank is still cold and not giving a lot of pressure.  That problem should go away once the just-filled tank gets to ambient temperature and the LPG pressure rises above the 'empty' tank.

------

None of which ties up with an escape of gas!!  That's an abnormal problem - you must try to track down the source.  As mentioned above each tank has a pressure relief valve - which should NOT vent in any ordinary circumstance.  I guess it is possible that you have two issues ... imagine if you have one tank not filling (because the 80% valve is stuck up) and the other over-filling (because the 80% valve is stuck up).   The filled tank is brimmed at 100% capacity with cold fuel.  You were probably squeezing in as much as you could because after all you expected more to go in?  None of it gets used on the journey home so its still at 100% capacity and warming up and expanding...  tank vents a spoonfull of liquid later - that becomes litres of smelly gas once it comes out.  Sound right?

Failed 80% valves allowing 100% fill are not uncommon, but they don't usually lead to venting - simply because some fuel is usually burnt off immediately by driving away.

Sill tanks are commonly 2 x 36L "water capacity", which should give an 80% fill of around 58L from empty, give or take.  I believe a few setups use 2 x 40L tanks, giving around 64L at 80%.  I'd bet your fills of either 70L or 40L point to the valves on both tanks playing up.

Replacement valves are cheap really. But replacing them involves dropping the tanks right out, and there is a good chance that the brackets/bolts/unions will be troublesome after some years of roadsalt, and further bracketry and pipework will be needed to restore the system  :(

cheers,
Ross Kennedy

[JimsMowing]

Thank you for all your responses. Some of them seem to make sense, but either way i think im out of my depth here and need to get in seen by a specialist. The only thing is most of the people i have spoken to dont do my system, as they need the correct diagnostic software for my system.

Boo Hoo!

So my trouble now is to find someone that deals with the one i have. Will keep you posted.

Thanks again.

Geoff

[Rossko]

err no diagnostic software or brand-name expertise is needed to look at tank or valve problems!!  But I expect their caution is because it MAY be something else and they don't want to send you away without a fix.

cheers,
Ross K