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Popped the hood today to take some pics of the engine for my album, and I noticed on the passenger side what looked like an oil breather cap for the valve cover. However, upon closer inspection I see it is attached to something, but has a provision for a hose. I can't see where that hose would go to though. Any ideas?
Probably not the answer you are looking for, and someone else will probably tell you for sure but my 96 F250 has that too and nothing is hooked up to it. I am curious too.
Others have described it as looking like the muffler on a small gas engine... and it is
When air from the air pump is not being injected in the Thermactor system, it is dumped to the atmosphere. To quiet down the putt-putt-putt that would result, it is fed through the little muffler.
If you leave your engine idling for a while, the PCM will dump air via the TAB and TAD valves. When it is dumping, if you put your thumb over the muffler output, you can feel it pulse. You can hear it too, though it's not very loud.
Older Ford systems had a fiberglass filter stuffed into the end of either the TAB or TAD valve (I don't remember which), and the air would come through the filter and out slots in the valve's steel housing. Those would make a much louder putt-putt. Of course they were louder, they were glass-packs
Interesting bit of knowledge there. Glad it was designed like that, and not some half baked idea to bypass a emission device. I am told this Bronco will pass smog, and even has a smog test sheet to prove it, so I am not going to worry about that small muffler anymore. Thanks for the info.