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??

 

-------------------------------------

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

'Curly'

 

-------------------------------------

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

'Curly'

 

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.

 

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.

 

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?

 

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?

 

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

 

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

 

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?

 

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?

 

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.

 

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.

 

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.

 

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.