mustang jaxon

Well, I feel like a certified dufus, but I just got a 1966 Mustang Coupe, just drained the oil, and NOW I cant for the life of me get the durn filler cap off...

Straight 6 Cyl

so the question is does this thing likely screw off, pull off, or some of both... I dont want to muscle it off only to find out there is some trick to it...

It wont budge, up, down, or twisting either way... tips appreciated... thanks

proeagles

It's been a while for me, but I recall that cap just pushing on and pulling off. Might try very carefully shooting some WD40 up around the tube to break it free. If you can't get that cap off I would remove the valve cover, second thought, remove it anyway just to see what the top of the engine looks like. Sounds like the oil has not been checked or changed on a regular basis and you may be dealing with a ton of sludge.

mustang jaxon

Looks like I wasnt as doofy as I thought, the filler pipe (tube) was damaged, entirely flat on one side... (That is not the normal shape, is it???)

I thought this was supposed to be round!!




Totally killed the (original??) filler cap though. But at least I can add oil now...

The car had been unstarted and sitting for a couple of years, and likely only occasionally driven 3-4 years before that... didnt think about checking the top end... I'll do that, Thanks for the reply... hope this helps somebody else, but this does not seem like a common problem.

69mach1377

Lesson learned...always make sure the fill port can be opened before draining. True for any automotive fluid.

User 92421

somebody probably crimped it on to keep it from blowing off due to excess blow-by

mustang jaxon

What's that?

bop11

TRamsdell, jaxon's question has a ring to it

mustang jaxon

You didnt answer my question, which was serious, really.

bop11

Blow-by occurs when the explosion that occurs in your engine's combustion chamber causes fuel, air and moisture to be forced past the rings into the crankcase. Your engine's rings must maintain an excellent fit in order to contain the pressure.
As rings and cylinder liners wear away they are less capable of maintaining this seal. Consequently as a car ages the amount of blow-by that occurs can increase.
Soot and deposits left over from incomplete combustion that collect on the rings can also inhibit their seal worsening blow-by. TR
Not only can rings wear but groves can form in the cylinder wall. If blow-by is so bad that it blows the breather cap off, it can also blow out crank shaft seals.
Modern cars use positive crankcase ventilation to direct the crankcase gasses into the air cleaner for burning in the cylinders. That works until the PVC valve plugs.
Excessive blow-by means the engine needs new rings and probably at least a hone on the cylinders.
If the blow-by is that bad, you probably see smoke out the tail pipe, especially when decelerating, with the foot off the gas, and oily plugs.
TRamsdell was making a point which does happen, and the cause probably has a RING to it.

mustang jaxon

Thanks for the thorough explanation... I am assuming that there would be other symptoms, like a tired engine, and as you mentioned smoke, maybe some noise...


replaced the cap with an aftermarket cap that only has a rubber stopper, and is working well... thanks a bunch...