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Discussion Starter #1
The last few months, I have been chasing boost leaks in my '16 cruze limited. First, it was the charge hose from the turbo to the intercooler (leak was at the intercooler) so I replaced that. was fine for a week or two, then the elbow on the other side of the intercooler started leaking, so I replaced that tube. but, I still have a leak at the inlet of the throttle body even with a brand new tube, no matter how tight I crank down the clamp. It is running better than before, but can rarely get over 5PSI... I did replace the throttle body / intake gasket like 2 months ago.... The only code I am getting is the famous P0299, and that only happens on a hill. are there any tricks out there to seal a leak there or could I have a cracked throttle body?
 

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2013 Cruze 1LT
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I just get it as tight as possible with a 1/4” ratchet and socket, no screwdrivers, not enough torque.
 

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Discussion Starter #3
I just get it as tight as possible with a 1/4” ratchet and socket, no screwdrivers, not enough torque.
yeah, I did that and it is still leaking... actually broke a hose clamp trying to get it at tight as I could.
 

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Discussion Starter #5
I see, how do you know it’s leaking from there, I assume a boost leak test?
yes... Can hear it hissing but can't feel anything. A few weeks ago, I did get a TPS Code (don't remember the #) but I cleared it, and had not had an issue since.
 

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yes... Can hear it hissing but can't feel anything.
A hiss can be accepted if its a small one, mine takes around 45 seconds to drop from 20PSI to 10PSI on a boost leak test (which I am told is more than acceptable), it leaks a bit from the Forge Atmospheric bypass valve and you can hear a hiss. How quickly is it dropping?
 

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2015 Cruze LT 1.4, aka Yuffie, aka RecklessRed
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A hiss can be accepted if its a small one, mine takes around 45 seconds to drop from 20PSI to 10PSI on a boost leak test (which I am told is more than acceptable), it leaks a bit from the Forge Atmospheric bypass valve and you can hear a hiss. How quickly is it dropping?
Yo! I just ran across a leak there too. Just today. How strange is that? . Been trying to chase it down for weeks. It's the nipple where the boost controller hose goes. It twists out. Mine was so loose that when we were checking it with a buddy with better hearing he though it was the hose that was broken or had a hole. The nipple unscrewed with zero effort. I wrapped the threads in some pumbers tape and tightened it back up. Shouldn't leak anymore. This was also the cause of erratic boost pressure. Probably the same on all of them.
 

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Yo! I just ran across a leak there too. Just today. How strange is that? . Been trying to chase it down for weeks. It's the nipple where the boost controller hose goes. It twists out. Mine was so loose that when we were checking it with a buddy with better hearing he though it was the hose that was broken or had a hole. The nipple unscrewed with zero effort. I wrapped the threads in some pumbers tape and tightened it back up. Shouldn't leak anymore. This was also the cause of erratic boost pressure. Probably the same on all of them.
I used soapy water from a spray bottle, mine bubbles a bit out of the holes that release the boost (which to my knowledge can't be fixed). Just the way it seals.
 

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2015 Cruze LT 1.4, aka Yuffie, aka RecklessRed
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"Just the way it seals."

Nah... If it leaks, it's not sealing. That should not leak under vacuum or boost. I actually just tested my hypothesis, which at this point I guess can graduate to theory. Considering that the WGA is what mechanically communicates the boost pressure, I was overboosting most of the time to like, 3-4 PSI. Now It only overboosts about 1-1.5, and I am sure I can just dial back the preload on the WGA a turn or turn and a half, and it should be spot on. Things that have vacuum or boost that are not supposed to leak, should not leak, so if it does, it needs to be tightened down. It has an o-ring on it too. Why the gasket if it's supposed to leak a bit? ;)
 

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It leaks on the aluminum piston part that meets the aluminum bottom, the bubbles come out from the vent holes. I dont want to thread hijack lol so probably gonna stop here
 

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Discussion Starter #11
A hiss can be accepted if its a small one, mine takes around 45 seconds to drop from 20PSI to 10PSI on a boost leak test (which I am told is more than acceptable), it leaks a bit from the Forge Atmospheric bypass valve and you can hear a hiss. How quickly is it dropping?
yeah, I wish mine dropped that slow.... 22PSI to 10PSI in like 10 seconds.... and it takes like 15 seconds at full pressure from my compressor to even get it up to 22PSI.... This is the only leak I can find...
 

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Discussion Starter #12
Yo! I just ran across a leak there too. Just today. How strange is that? . Been trying to chase it down for weeks. It's the nipple where the boost controller hose goes. It twists out. Mine was so loose that when we were checking it with a buddy with better hearing he though it was the hose that was broken or had a hole. The nipple unscrewed with zero effort. I wrapped the threads in some pumbers tape and tightened it back up. Shouldn't leak anymore. This was also the cause of erratic boost pressure. Probably the same on all of them.
never thought of using plumbers tape... that stuff is cheap... it is worth a try! Thanks for the idea!
 

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Discussion Starter #13
well, I just went out and wrapped about half a roll of plumbers tape on it, and re-boost leak tested it, and it is much better! takes 30 seconds to drop from 20 to 10 PSI... still can hear a little hiss from the throttle body, but nothing like before... I will drive it tonight and see if it runs any better...
 

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well, I just went out and wrapped about half a roll of plumbers tape on it, ...
A little goes a long way... and the direction of the wrap also makes a difference.
 

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2015 Cruze LT 1.4, aka Yuffie, aka RecklessRed
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Yeah. You dont need much. And yes, wrapping against the thread (righty tighty, then wrap the opposite way) will stop it from bunching up when you go to thread it on. If it works, it works. I love little things like that. Superglue is also SUPER handy to have a couple tubes off. Small, light things or slightly loos little inner trim pieces that rattle, just a tiny drop will hold it in place in a pinch (don't use too much you will break things if you need to remove it again. lol)
 

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