replace petrol cap (again) or not?

Couple of things. Firstly it's not pressure, it's vacuum. Secondly it's not supposed to suck air in when you remove the cap; it means a vent is blocked, probably, and in extreme cases you can get poor running or even cutting out because it's effectively sucking back against the pump. Usually it won't do any harm though.

I would replace the cap for the correct one in any case. Perhaps you can transfer your original lock barrel over if it still works, or get one ordered to match your locks.

"Chandy" wrote in message news: snipped-for-privacy@g47g2000cwa.googlegroups.com... Hi all,

Okay, it's a 96 1.3 escort. Had to replace my petrol cap a while back as it suddenly wouldn't lock. Halfrauds wee thin locking one was bought which did the job but wasn't anything like the depth of the old one yet was supposedly the right one for me. Thinking recently, this replacement doesn't seem to hold anything like the pressure (take it off at the pumps, nothing like the hissss of old, almost negligible really) so I figure it's obviously crap and costing me fuel, but how much? If I effectively have a vent at the end of the line instead of a sealed system and therefore maybe only a few hundred millibars pressure then I can see it potentially squirting out, what, 1/2 litre every 50 miles or so? (really just a picture in head type of calculation). Plus what would the engine be thinking about this lack of pressure? Or would nothing at that end notice the difference? Have a replacement proper cap (or so they say) available for £21 odds. Worth it in lost fuel? I have no real idea on this one.

Chandy

I doubt whether losses could be calculated. But an insecure petrol cap is an mot failure, so I would say, get the ford cap and return the crap one to halfords as it is 'unsuitable for the purpose supplied'

mrcheerful

I'd suggest you do as the man above says, and get it from your local scrapyard. Certainly around 1996, the Ford petrol caps with central locks were easy to swap locks from cap to cap....

Artie