Pulled my 73 out of the garage yesterday to take it for a little spin. As I normally do when i first pull it out I popped the hood and gave the motor a once over and checked the oil. Well there was hardly any oil in the motor. Walked around to the other side and saw that my oil fill cap was not on the valve cover. Had an (OH S*&T MOMENT) looked around and it was sitting on top of the firewall and there was oil sprayed everywhere so it must have come off when I drove it last week.

That being said I know I did not take it off the last time I parked it. Is it possible that it blew off of the valve cover due to compression?

My first step in solving this problem will be to change the oil and filter and buy a new fill cap. Can anyone think of anything else that may have caused this?

If it helps the car is a 73 with the original 454 in it.

Ive had blow by cause the dipstick to blow out of the tube at the track, so I would assume that this is usually the path of least resistance for something like this.

Your cap is just a push in style, so maybe last time it was out it wasnt seated properly, and or maybe its edges are worn. It would otherwise seem very odd to me that this would get pushed out before a dipstick.

The rubber push on style of oil fill caps, are available at most parts stores, quite common to replace.
Like all rubber products they have a tendency to soften up, or harden (depending on it's environment).
My belief is it was worn out, and simply did not fit as snuggly as when new.

I think you guys are correct. I'm the third owner of the car and there is no telling how long that cap has been on there, it may even be the original. I'll be picking up a new one today. It's to nice outside for the car to be sitting in the garage.

Thanks for the replies.

"As I normally do when i first pull it out I popped the hood and gave the motor a once over and checked the oil."


OUTSTANDING!!!!!!!!!!!!!

I saw a dip stick blow out of an engine once and it turned out the exhaust pipe was blocked....it looked fine from the outside but had collapsed internally....might be something to check.

At least you were not driving when you noticed the cap was missing - like I did. I had a breather cap with the baffle plate on my VC. I hated how the plate restricted oil flow when doing oil changes. So, the last time I changed oil, I removed the baffle plate and replaced the oil cap. I went for a drive, saw tons of smoke and realized oil was gushing all over my engine bay. What a mess. Got home, cleaned up everything, re-installed the baffle plate and the breather cap.

Don't know how old the cap is, but my 73 I have changed the cap a couple of times, because they harden up and shrink a bit. If yours is older, you should replace it.