Road draft tube…

[KPotter44]

Hello all. My ‘99 Dodge has always been parked in gravel until just recently. We had a concrete pad poured and then put up a metal carport to protect it from the sun. Well, the road draft tube drops a few occasionally. So I found a 3” X 8” aluminum “can” on eBay. It has brackets for mounting and a threaded hole at the bottom for a petcock. The top has a small filter and there are three fittings about 3/4 of the way up. Two are capped and one has a barb fitting to attach the hose. My thought were the fumes/vapors would escape through the filter and I could open the petcock occasionally to drain the liquid. Not working as I planned. The fumes/vapors contain a lot of liquid that is covering the crossmember and everything else near there. I need to cap the top, but will there be crankcase pressure? And if the crankcase pressure has no place to go, what then? Thanks.

 

[petersonj]

The normal cylinder blowby into the engine crankcase needs a free path to ventilate to atmosphere. If that path is blocked or severely restricted, crankcase pressure will build until it finds a new path to atmosphere, usually through engine seals or gaskets. Then you will have a much larger pool of oil on your new concrete.

It is possible to have excessive flow through the crankcase from leaking vacuum connections anywhere in the vacuum system. The vacuum pump pumps directly into the engine crankcase. The extra air flow from leaking vacuum line connections combined with normal engine blowby could give you an extra few drops of oil on the ground.

- John