Old Style Filler Cap - Breather Hole

[Tazio]

My crossflow has no tank breathet, and no breather on the filler hose, and I know it needs one, so typically where is it normally drilled.  This cap is new to me and the car and I cannot find a breather hole in it....

[Tazio]

Inside seal

[Sooty]

Alan, I had one of these originally and had no issues with tank vacuuming as a result of suction from the pump so I think it must vent through the lock mechanism

[Tazio]

David,

Thanks for that. I 've run the engine, just to check for plumbing leaks on the dry sump and coolant systems, one day the motor was fine, second day she was missing a little, remembered old threads re breathing and vacuuming, and as I am running an electric pump, just needed to check how it breathes.

[SM25T]

Is this a breather hole ?

 

[Tazio]

Erm........I think you maybe correct, doh...question is, is  it the typical size required and should it be able to cope with a Facet redtop pumps demands?  I'll run it with the filler cap open first and see how she goes.

[rkeywood]

Hi Alan, if that's the cap you had from me then yes, I was using a Facet pump and raced with it without issue.

[Tazio]

Thank you....appreciate the info., may have to look for another cause....