patuww

I checked the oil Thursday and I couldn't believe what I saw. The oil cap was only half there. The threads were still in the engine but the top was missing. Of course the threaded part is hollow, so all I had was the threads in there with hole slightly smaller than the oil fill hole. Crappy thing is I could have been driving around up to a week with no "oil cap" on. There was some splatter on the hood and engine, but did not seem to bad. I was down about half a quart (half-way on the dipstick).

Took in to Honda to get a replacement cap and they said they wanted to test for excessive pressure. They said all was ok, but then the tech said it was down a Quart and a half so he "filled" it up (figures, moron). I will post pictures of the oil cap remains tonight. Just want to see if this has happened in the past.

Also, anyone that has lost a cap....It is possible that this happened, because it was only a matter of time on mine until the "threads" worked their way out since they were not secured. At that point it would have just looked like I did not screw it down tight and it worked its way out.

Lurker1222

wow... I can't say I have ever heard of that..

wow...

WPS

maybe it was screwed on too tight

xviper

If you look on the underside of the oil cap, you'll see that there is a recessed plastic ring. I have, on many occasions, removed the oil cap and discovered that the ring stays on the top of the engine. It is not always easy to see it. If you leave it there and in the process of putting oil in, you shift that ring, it will not mate up properly with the groove in the oil cap. When this happens, the oil cap will not screw down completely or evenly. Knowing how some people use gorilla strength to put on their oil caps, this puts an uneven pressure on the top of the cap. Over time and with the engine vibration, I can easily see how the cap could crack. I'm sure this is the reason why many an oil cap have mysteriously unscrewed themselves and fall down and wedge themselves between the top of the tranny and the firewall.

cdelena

It should also be noted that the stock cap is made of a fairly brittle plastic. I have one cap that has a length of the threads broken off. It has not been a priority for me but every time I remove the cap I think I should find a cheap metal one that will not break.

terd ferguson

I had a small piece of the thread of the oil cap break off and it (the broken piece) stayed lodged in the threads of the valve cover. I noticed it when I tried to swap the factory cap for a Spoon cap and it wouldn't screw all the way down (this was the first day of ownership).

Yellow Streak

I had it happen at BeaveRun - fortunately it was practice and not the race. I replaced it with an aluminum cap - that really shouldn't crack like the OEM one did.

Stealth Operator

Those metal oil caps made by race manufacturers serve a purpose.

Ztec

Coraldoc had his cap break in a similar manner

Muz

Check under your bonnet liner for oil saturation.