what is that tube, anyway

Like a lot of folks, I got tired of the air inlet for the PCV from the big air pipe after the air cleaner, puking up oil every once in a while and gumming up the throttle body, so I decided to swap over to one of those cute little filters that go over the inlet on the cam cover. (this is a honda b16 4 cylinder). The factory has that inlet connected with a short little hose to like an 11 mm diameter piece of steel tubing that goes into the air pipe. But that piece of tubing is siamesed for a ways with another piece of steel tubing which has a long hose at either end that goes from the block to the throttle body; since the hose at either end is plenty long enough I just took out the whole thing and used a piece of hose to go straight through, which is when I discovered it's a coolant hose.

So, the question is, why, instead of just running a foot of hose to carry the coolant to the throttle body, do they use a foot of hose to run it through a steel tube siamesed to the steel tube that carries the input air for the PCV and then out another foot of hose? Are they trying to heat the air for the PCV up before it gets into the engine? Are they trying to cool the coolant before it gets to the throttle body? The mechanical stability for the thing is entirely from the PCV inlet connection at each end.

What gives??

Reply to
z
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They're guaranteeing that the pipe won't get iced up in winter time by keeping it (toasty) warm.

'Curly'

Reply to
motsco_

That's the state of PCV systems today. In order to lower emissions they run them so near the ragged edge of too little flow to keep the engine clean that they have to HEAT the PCV air to keep the gookum from condensing out and clogging it. This is why so many engines die of "sludge" in the oil these days- the PCV systems are no longer flowing enough air to keep the internals of the engine as clean as they once did.

Reply to
Steve

"z" wrote in news:1171393512.507664.155340 @v45g2000cwv.googlegroups.com:

If it's "puking up oil" then you've got a blowby or a sludge problem. That's NOT normal.

You'd have been wiser to spend your time and money figuring out what's wrong with your engine instead.

(this is a honda b16 4 cylinder). The factory has that inlet

Yep. Runs under the throttle body.

That's possible. Icing can be a problem with small diameter lines that carry ambient-temp air.

Although if that were the aim, don't you think they'd bond the two lines together directly instead of insulating them from each other with that black rubber thingy?

Reply to
Tegger

Mm. Never thought of that; heating to prevent the gook and/or ice from clogging. Thanks, guys.

Reply to
z

Well, not a visible lot, but over the years I notice that some oil is now resident in the air filter pipe when I take out this PCV inlet; and since the last time I had to replace the gunked up idle air adjustment hole, which ended up with the mechanic installing a defective distributor for which I ate the cost, a story posted elsewhere, I decided to avoid it.

What black rubber thingy? On my engine, the two are bonded metal to metal. Does the teg have a rubber spacer between them?

Reply to
z

"z" wrote in news:1171469121.219308.313920 @a75g2000cwd.googlegroups.com:

It's normal to have a light film of oil in the vicinity of the breather inlet from the air cleaner pipe. By "light" I mean a film you can see as wetness on the plastic, but that doesn't have any thickness.

If that film has turned into gunk and is fouling the throttle plate, then there is an engine problem.

In mine (2nd gen), yes. Other than your guess, I can't see why they'd have the two pipes together. Maybe Comboverfish has a better idea.

Reply to
Tegger

Tegger wrote in news:Xns98D7A97E6B6FEtegger@207.14.116.130:

I should have actually looked before going by my flawed memory.

Those pipes ARE in contact on my car, just like yours. The black thing just seems to cover the seams or something.

In fact, I have THREE lines bundled together there. The third one is the vacuum line for the Air Boost Valve.

Reply to
Tegger

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