When I open the cap to fuel up air rushes in as fuel used appears to have created a vacum. 

 

Anything to worry about?  Cure?

 

 

1 hour ago, irc said:

When I open the cap to fuel up air rushes in as fuel used appears to have created a vacum. 

 

Anything to worry about?  Cure?

 

 

Usually it’s just due to heat and doing its job

Completely normal, nothing to worry about.

Gone are the days of vacuum fuel starvation. My Mums Ford Prefect 105E (81MPJ!) regularly had that issue on loner journeys in the summer. On one occasion when we’d had to stop as the engine was hunting like crazy and finally stalled, a passing RAC patrolman on his bike stopped and asked we were OK. Mum explained that unfortunately we weren’t members and he said don’t worry about that. He asked what the problem was and Mum explained what had happened, and the patrolman walked to the back of the car. He then opened the petrol cap and with a huge rushing of air and a bang as the tank returned to its correct shape, the problem was solved. Mum now made sure she’d vented the tank at the start of any longer drive she undertook. 

When filling the tank you should stop at the first click of the pump. If not the canister can fill with fuel. 

Thanks for all replies.