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What kind of hose is good to use for a PCV line? Something oil resistant and won't collapse under vacuum.
Keep in mind that any soft hose, especially big fat ones, exposed to vacuum, can collapse due to the vacuum. Not likely on small diameter hoses, but I recall once in our dynamometer room, a certain engine was giving us fits with overheating. This particular one had a standard radiator mounted on the test stand. Numerous hoses, wiring, and such obscured a view which amazed me when I spotted it. The mechanic had used a non-spiral wire containing lower hose, and it was sucked FLAT, effectively shutting off coolant flow.
Yeah, that's why they use the spring inside the lower rad hose, the pump
pulls through there, and they can collapse. I have never, EVER seen a PCV
hose,or any hose for that matter, collapse on me no matter how cheap it was.
I used this:
That cheap hose that comes with universal catch cans. Here's the thing, while
it's very soft and pliable there, it hardens soon after it's in place. I used
it on my HHR, and a turbocharged 2.0, never collapsed. I won't use that in
the Mustang, so it looks good, but I have used that a lot.
I got it with the catch can I bought, but it doesn't fit over the PCV or the nozzle on the
intake plenum. They provided two sets of fittings for the catch can, but the car side
fittings are too big even if I were to use the smaller fittings on the can. Not sure I would
even use this hose knowing how much vacuum is present on the PCV line now...
Won't be able to mess with it again for a few days.
Oh, and imp, I just experienced my first partially collapsed hose.. The bend is too
steep from the PCV to the catch can, and there is a LOT of vacuum on the PCV
line, so I see why they use the hard plastic. It still works, I just need to move the
catch can somewhere else so the bend is not so steep. It kinks the hose just a
tad, but once it warms up, it starts to flatten out in the center, not blocked, there
is still vacuum. The catch can has a dip-stick to check the oil level in the can,
and lots of air is pulled in through the hole, enough to cause the motor to run
rough with that unmetered air. Smaller diameter hose would probably work
a little better. I will have to redo the system once I get a replacement bracket,
the one it came with broke. I was going to mount it on the intake plenum,
but the clamp broke... Asking the reseller for a replacement...
Yep, drove the 'Stang all night 473+ niles, and both lines partially collapsed. The can to the
plenum was oval, not pinched. The PCV to can was pinched at the center, but there was still
ample vacuum. I pulled the measure stick out, and it was sucking in air pretty good, and the
car idled rough. Yep, will be doing this over again as soon as I get the replacement bracket.
02-16-2018, 10:54 PM
