mrbond413

Yesterday was the first semi nice day we've had in Salt Lake City for a while now. We just had a snow storm that blew the inversion out of the valley and temps were finally higher than the teens with the sun out. I decided to pull my S out of the garage and take it for a spin since I haven't had a chance to since early December. I popped the hood to check the oil and went to spin the oil cap off but the top of it just came off without any effort and the threaded part was still in the hole. My guess is that it's from the engine being warm from last time I drove it and then the freezing temps made the valve cover shrink and snapped the top off my oil cap. Has this happened to anyone else? Or is there another cause to why this would happen?

chef-j

Oil cap? wow that's suck dude.

zeroptzero

I doubt it's temp related, otherwise we'd have seen thousands of them up here in our area as people do that on a daily basis. I'd say it was either a defective cap or it was over-tightened at some point in the past. Perhaps the rubber gasket ring on the underside of the cap has worn out and the cap was over-tightened to compensate for the lack of rubber. When I got my car the rubber ring was worn out, after replacing it the cap fit much better.

s2cho

same here, and i live in co and its getting hella cold!
like in the singles 1-9 degrees F

so after every oil change i rub some oil on rubber gasket to make sure
it fits well and it will help from drying out

mrbond413

I got home from work and looked at it a little closer and it doesn't even have a rubber ring on it. I've never over tightened it though, just snug. I also checked my civic and it doesn't have one either. Guess I just haven't looked that closely at them.

zeroptzero

that is the issue, the rubber contact surface wears out over time and then it doesn't fit as designed. That could result in a tightening issue - over tightened or under tightened and maybe it even increases vibrations at the cap.

The rubber ring is replaceable , you can order it as a part from Honda, or you can get a new cap altogether. The rubber ring is like a tiny squeegee, which provides some grip and a better seal when the cap is installed.

ahrmike

Its plastic too, so its going to definitely break after exposed contact with petroleum... Just get a "stant" oil cap. It has a S on it...which looks suprisingly similar to the S2000 s. hehe

DFWs2k

Mine cracked too, sounds just like what happened to yours, except it was this last summer, so not related to temp. Luckily I was at a buddys house and he had an extra oil cap from a d series.

zeroptzero

I bet 99% of S2K owners with worn out oil caps never know when the rubber ring has worn out, you really have to examine it closely on installation to figure it out.

Robert O

These caps are designed to float on the gasket when installed. If the gasket is worn to a degree that the flange of the cap is hard against the cam cover,expansion and contraction of the cam cover will most definately cause breakage. The cap does not expand and contract at the same rate as the aluminum cover.No mystery there. You can feel if the cap is making solid or gasket contact when you tighten it.