ok... I know its volvo300mania but the volvo 66 is the little cousin of the 340 and they are quite similar to the volvo 343....

I could do with some advice from general car gurus anyway...

ok heres the deal...

this is prob a very obvious question and probably relates to all classic car fuel tanks... but...

Im used to working on the volvo 340 which has a fuel overflow pipe and an expansion tank system for the tank.


What I dont understand is how does this tank vent as the tank heats up and the fuel evaporates in the hotter weather?

On the 340 is an overflow pipe plus a additional expansion tank system on the later cars. The earlier cars dont have the expansion tank nor an overflow pipe

Im puzzled by this volvo 66 tank as there are only 3 pipes on the tank- first, the inlet - with the filler cap on, second the smaller pipe from the top of the tank to the filler pipe ( that I guess allows air out the tank as fuel flows in) and third the outlet pipe which goes to the fuel pump.

However, as the tank heats up on a warm day how does the tank vent or release this pressure?

I guess the 340 can vent via the overflow pipe?

BTW the overflow pipe isnt present on the early 340s.......

cheers guys

S

Picture here....

http://i35.photobucket.com/albums/d156/ ... C_0032.jpg

the later 340s that have the expasion tank also have a roll over valve in there to stop petrol leaking if the car over turned

thanks dafodil but how does the tank vent as it warms up in summer? As it warms more fuel evaporates so doesnt this vapour need to vent eventually? ( no pun intended! )

there is a vent pipe on the 340s it is clipped to the edge of the tank and the pipe runs around the back
i think it connects to the filler pipe or the venting bit in the car

volvo 66 will spit it out through the filler tube!

but what about the vapours producted as the fuel evaporates more at higher temp?

volvo 66 will spit it out through the filler tube!

... same goes for the fumes

there is quite a lot of space in the filler tube, I never have had any problems on our DAF's with excess of fuel after filling up.

there is a small hole in the filler cap that lets the pressure off, and lets air in as the tank is emptied.

cool... all makes sense now..

thanks again for your info wouter!