Hello all. 2012 2.4 equinox w/160k miles. I have a loud whirring sound at idle. It is resonating throughout the engine compartment, but seems to be more on the driver's side. It sounds like a bearing howl from an alternator. I have a video which I will try to upload which demonstrates it well. When cold, it doesn't seem to do it. It will do it after a few minutes of running. It started just after I replaced my holey and rusted and ripped oil dipstick tube. Now that I replaced the oil dipstick tube with a new one, I have this noise. Now if I pull out the oil dipstick, the noise stops. There is a vacuum present at the dipstick tube opening. I am not sure if I am supposed to feel any there. There is vacuum at the oil fill cap, too. It will suck the oil fill cap down. There is pretty strong vacuum at the short "L" hose on the left side of the intake plenum which goes into the valve cover. I have just recently cleaned out a non-blocked pcv hole in the intake manifold and head. It has never been blocked. The noise sounds like a bearing howl, but it obviously is not a bearing since removal of the oil dipstick will immediately stop the noise. This is a pcv air issue that I probably had for a long time and is only showing now with a new dipstick tube that doesn't leak air. I tried looking for air leaks by blowing into tubes attached to the intake. I cannot blow air into the hose that goes to the brake booster, nor can I blow into the hose that goes to the fuel vapor purge thing. I am worried that a year ago or whatever, I may have drilled open the pcv hole in the intake manifold like someone did on the internet. If I did it, I know it was the absolute minimum overdrill, just enough to scrape the sides of the hole, you know? Do you think that minimal amount of extra hole created too much vacuum in the crankcase, and the noise is coming from resonating air trying to get sucked in?
Whirring air sound, possibly related to enlargement of pcv hole in intake?
- Thread starter mirageman
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I took off the intake again to check that pcv hole and indeed it is larger than the other I saw in another post. The pic with the green gasket around the pcv hole is mine currently. It is much bigger than the blocked hole in the other pic from another post on this site.... I thought if I did drill it, it was a year ago and just a bit. I think I went too far. I also took a video showing the whirring noise and how it stops with pulling out the dipstick, but it seems like this site will not accept my format. I think this bigger hole might be the problem, sucks too much, and perhaps not enough crankcase vapors to keep up. This manifested after replacing my rusty, leaky oil dipstick tube. A new intake manifold is not bad at $125 at autozone and you can go the 20% off route with free shipping, but I think I'll try to take a soldering iron to that hole there and try to make it a virgin again before spending that money. There are videos of very similar sounds but different cars with actual pcv systems. This one comes close:
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FIXED! lol... soldering iron used to swipe some plastic off a fin on the intake manifold. Carefully smothered it all in there. Then took a torch and with a small flame bubbled all of it to hopefully do a complete melt. After it cooled, I heated a 3/32 Allen key and popped a hole in it then torched it again. 1/8" Allen key fit in the hole before, now a straw from a carb/choke cleaner spray just barely goes in and out. Now power has returned, actually! No whistling at all. No difference in removal of oil dipstick. Oil cap still gets sucked down, but no changes in engine sound. Moral of the story... don't oversize your pcv orifice... not much, anyway. Whew!
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Travis Bickle
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Dude that is awesome. Macgyver would be proud.
You fixed the whistling noise. But you’re still left with the faulty orifice design. There’s no fixing that. It’s still going to suck moisture into the engine and there’s nothing you can do about it. MacGyver it shut and add a PCV valve.
Travis Bickle
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Or put a catch can in, AND yank the intake manifold off every 8,000-10,000 miles or so and clean it out.
Not hard to do at all, I just put new plugs in, and pulled the manifold & cleaned the orifice while I was at it.
Much less oil consumption now. I'll do it again when it starts using more oil.
Catch can is easy too, and it works. Empty it every few weeks, see all that crap that DIDN'T make it into the engine.
Winning.
Not hard to do at all, I just put new plugs in, and pulled the manifold & cleaned the orifice while I was at it.
Much less oil consumption now. I'll do it again when it starts using more oil.
Catch can is easy too, and it works. Empty it every few weeks, see all that crap that DIDN'T make it into the engine.
Winning.
cpscoachtech
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I recently had my manifold off and cleaned it and decided to make it just a wee bit larger hole. I believe I went too big and it started the whirring sound. Quite annoying. Not sure what to do other than remove the manifold and drill a smaller hole into a small piece of metal and jb weld it over the larger hole to stop the vacuum. I put the old unvented oil cap back on and the noise subsided. Now I wonder what issues could be happening. Should I go back to the oil catch can I have installed and repair the pcv hole on manifold or leave it as is? Ironically, I think it was worse because I was changing the timing chain and guides at the same time and I put the main seal on the "harmonic balancer" backwards. So the pressure was building and a 2 hour drive pushed all my oil out of the seal. So, larger pcv and seal that was not sealing on the main equaled lots of noise. Yeah, I feel stupid but I didn't know which way it was suppsoed to sit. Makes sense now. Live and learn I suppose. 2013 Nox with 2.4l Ecotec. The question is how large is the actual hole supposed to be?
Just buy a new plastic intake. Its cheap. Before you install, rather than enlarge the orifice, drill a hole from the top into the cavity so you can clean the orifice without taking the manifold off again.
