Author Topic: Fuel leak...  (Read 188 times)

Will

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  • Location: Essex/London
Fuel leak...
« on: 23 June 2019, 10:57 AM »
Strange one - I left my 450 standing for a couple of weeks and after a while we could smell petrol.  I went to start it and it appears the whole lot has somehow drained out.  I guess it's hard to tell without looking but are there any obvious places to start chasing the fault? It's going to be hard getting it to a garage like this and I don't have lots of time to do the work myself right now. Any thoughts appreciated!

daantjie

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Re: Fuel leak...
« Reply #1 on: 23 June 2019, 12:44 PM »
Check the fuel package at the back of the car, RHS. Very common for dry rotted hoses to leak fuel. Take this as a good opportunity to refresh all hoses. Cheap insurance against a Car - B - Q :o
Daniel
1977 450 SEL 6.9 - Astralsilber

gavin116

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  • 1979 450SE
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Re: Fuel leak...
« Reply #2 on: 23 June 2019, 02:35 PM »
Hi Will

You can bet it will be the main fuel line from the fuel tank to the accumulator. In fact all the fuel lines will probably be toast. But that particular line will be fragile and will just crumble in your hands, so now that the tank is dry this will be a good time to change it. The is a rather large nut on the other end, so you will need to source a spanner of the correct size before you begin. There is also a fuel strainer that you should replace at the same time.

I had a fun time trying to change the said pipe without draining the fuel tank, and failed dismally...  ;D  You'll see what I mean if you look at this post: https://forum.w116.org/test-drive/my-first-w116-here-at-last/msg89761/#msg89761

Happy 116ing

Will

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Re: Fuel leak...
« Reply #3 on: 24 June 2019, 12:21 PM »
Thanks guys! Very helpful indeed - having said that, fuel lines are probably beyond my meagre skills. Maybe I can get a mobile mechanic to have a look. At least the car is not completely inaccessible.

Need to get on it before this rare good weather we are having ends!

revilla

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Re: Fuel leak...
« Reply #4 on: 25 June 2019, 08:53 AM »
Hi Will,

If I understand correctly, the “drain” happened while the car was sitting unattended. Then the leaking fuel must have evaporated leaving no trace of where the leaking point was at.
I would put a couple of liters of fuel in the tank and:
1) first observe if there’s leaking by gravity in the rear around the fuel pump area including the draining hose and line towards the FD.
2) start the engine (take all safety measures including fire extinguisher on hand with somebody with hands on ignition key ready to shut off the engine) and look in the fuel distributor area (air filter removed) and all along the fuel lines under the car.
3) is the practice of sucking the neighbors’ fuel tank active where you live?  ;D
Good luck
Let us know of your findings
Cheers
Robert
W116 1977 280SEL & 1979 280SE

Will

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Re: Fuel leak...
« Reply #5 on: 27 June 2019, 11:26 PM »
Thanks Revilla,

Yes that is exactly what happened, I think. I can still smell the petrol, but my nose isn’t that sensitive to sniff out the precise location!  I’ll give it a go with a few litres as you say, ideally that would at least allow me to get it on a trailor or something.

I’m fairly new to the area but think/hope I can rule out theft!

Cheers

Diesel 617

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Re: Fuel leak...
« Reply #6 on: 28 June 2019, 05:46 AM »
I found ,my fuel leak under the rear subframe. I ended up lowing the differential to give myself more access as it still quite a tight fit to the fuel pump. Forward of the that area the lines are easy to access.
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


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