Turbo related noise?? Waste gate?? Idk

handymanthony

handymanthony

Member
Hey all,

After getting a bunch of $$$ paid for fixes, a buzzy, high pitch noise started happening that sounds turbo related but not my actual turbo?? It sounds like fluid is being blown off somewhere. If I floor it, it will cut in and out like something is getting cleared, then go away. Or if I just drive normally for about 3-4 min it goes away. The noise will happen almost anytime I shut off my engine even for just a few minutes. It doesn't affect how driving feels at all, just ugly sounding, but obviously not a sound that I want to hear. Any thoughts? I'm wondering if it's the waste gate or something? Video link attached.

 
My first guess would be the overboost relief valve:

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In theory it should never open, it's a failsafe valve, designed to pop open if boost exceeds 12(ish)psi and the wastegate isn't doing anything about it. Try wiping it with a paper towel- if it's wet with fresh oil, it's been leaking.

They get tired with age and can start to pop open at lower and lower pressures. If you have a boost gauge (so you know if it's overboosting), you can replace the valve with a 1"BSP Taper threaded bung.

The other possibility is the short rubber hose between the turbo and the inlet manifold (black with spring clips in the picture above). The factory installed it with worm-drive clamps, which rely on the springiness of the rubber for clamping. As the rubber hardens with age it can start to leak. Replace the hose with a silicone hose, and the worm clamps with T-bolt hose clamps.

(The picture is of a Hyundai D4BF with factory spring clamps, which maintain their clamping force regardless of what the rubber does. They have to be carefully specified and sized for the application, and I'm not certain they would work on an older engine).
 
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I agree with the blow-off valve. I replaced mine with a 1" NPT black iron pipe plug (w/ PTFE thread sealant paste)... it's been fine that way for years now.
Apparently my van has a replacement wastegate actuator with a minimum setting of 12psi so even a new replacement valve was popping frequently.
 
Thanks for your input fellas. Took my baby to a shop and it turns out my turbo fins are scraping on the housing and a connector rod bearing is going out which sounds like has led to the beginning of the end for the lower part of my motor. I think I'm going to bite the bullet and do the Hyundai motor swap. It looks like the turbo would be a separate item that's not usually included with the Hyundai engine correct?
 
handymanthony said:
Took my baby to a shop and it turns out my turbo fins are scraping on the housing and a connector rod bearing is going out which sounds like has led to the beginning of the end for the lower part of my motor.
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That sucks... but IDT the sound is actually related; it sure sounded like the blow off valve in the video. And how did they diagnose a ConRod?
handymanthony said:
It looks like the turbo would be a separate item that's not usually included with the Hyundai engine correct?
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Nope... it's included. That's part of why the swap is pretty much an easy choice.
 
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sk66 said:
That sucks... but IDT the sound is actually related; it sure sounded like the blow off valve in the video. And how did they diagnose a ConRod?

Nope... it's included. That's part of why the swap is pretty much an easy choice.
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I agree, the noise doesn't sound like the turbo itself and I can actually hear a healthy, smooth whoosh from the turbo underneath that other sound, which doesn't sound like metal scraping metal to me. I am a bit skeptical about how thorough they were, although they've done good work for me before. They didn't actually open up anything to confirm the bearing situation, because they said they'd need to drop the engine, just "detected" bearing noise at the bottom of the engine, guessing with a mechanics stethoscope. So they were going off that.

I'll open up my turbo to double check it. Last time I looked at it, a month ago, the fins spun real smooth and there was no play at all on the spindle..and besides the noise she's running smoother now than ever before after spending like 3000 on maintenance.. I do have the 1" plug and thread sealant, waiting for my boost gauge to come in to put that in. Hopefully that'll make a difference. Might take it to another mechanic just to double check.

But long term plan was to eventually do the Hyundai swap anyway. I was just hoping a couple years down the line
 
If it's conrod bearing going, you can get away with just fitting new bearings without removing the engine from the van- just drop the oil pan and conrod bearing caps. The crankshaft is nitrided and it takes a *lot* of abuse before it needs replacing.
Crank main bearings require removing the engine (so you can take the flywheel and oil pump off to drop the crankshaft) but they don't tend to make knocking noises.

I'd be surprised if the turbo has developed enough sideways play to scrape the housing in just a month, but it doesn't take long to pop the rubber inlet hose off and double check.
 
Pop the compressor inlet pipe off and have a look for yourself. I'm with @sk66 on this one. Seems very fishy.

When I nuked the turbo on my Datsun I had enough axial play to easily see and feel it by simply grabbing the compressor shaft and moving it side to side. It was puking out oil and smoking like a scene from a Cheech and Chong movie. And there STILL was not enough play for the compressor to touch the inside of the housing.
 
So it seem like my original suspicion of the waste gate was correct. I didn't see it when I was poking around before but now there is oil obviously coming out of the wastegate. Also I put on some ear plugs and was able to track the sound to the wastegate... So I'll be getting a new one ordered. Definitely disappointed with that mechanic! Seems like they didn't even try. In the mean time, there shouldn't really be much issue for me driving it right? I'm basically just getting lower boost from my turbo?
 
handymanthony said:
So it seem like my original suspicion of the waste gate was correct. I didn't see it when I was poking around before but now there is oil obviously coming out of the wastegate. Also I put on some ear plugs and was able to track the sound to the wastegate... So I'll be getting a new one ordered. Definitely disappointed with that mechanic! Seems like they didn't even try. In the mean time, there shouldn't really be much issue for me driving it right? I'm basically just getting lower boost from my turbo?
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Wastegate or overboost relief valve? if the overboost relief valve (see GBNZ's photo above of the part in red), then yeah, no worries if you are leaking a bit there. You're just losing some power in the process. If it's the wastegate that's leaking, that's another story....
 
detroadster said:
Wastegate or overboost relief valve? if the overboost relief valve (see GBNZ's photo above of the part in red), then yeah, no worries if you are leaking a bit there. You're just losing some power in the process. If it's the wastegate that's leaking, that's another story....
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Yea the wastegate actuator. There's no oil coming from the over boost valve. What do I need to worry about for the wastegate?
 
I had oil coming from my wastegate actuator... it was engine blow-by being pushed by the turbo. Although I can't imagine how oil comes out the bottom w/o the diaphragm being blown, so I suspect my actuator is also bad. Doesn't seem to ever make more than 13-14psi boost, and it only makes that much when really accelerating hard; so I'm ok with that.
You could test it with a bicycle pump pretty easily, but my guess is it's blown if you can hear air coming from it.. And I would guess that means it's also causing the pop-off to blow when driving because it's not limiting the boost to a lower level.
 
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sk66 said:
I had oil coming from my wastegate actuator... it was engine blow-by being pushed by the turbo. Although I can't imagine how oil comes out the bottom w/o the diaphragm being blown, so I suspect my actuator is also bad. Doesn't seem to ever make more than 13-14psi boost, and only when really accelerating hard; so I'm ok with that.
You could test it with a bicycle pump pretty easily, but my guess is it's blown. And I would also guess that means it's also causing the pop-off to blow when driving.
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Got it.

So the wastegate uses that hose that connector to the compressor side of the turbo to sense boost. As boost increases that moves a diaphragm inside the wastegate which in turn moves that rod/arm that protrudes from the wastegate. That arm opens up a flap inside the turbine housing and bleeds off exhaust causing the turbo to slow and boost to be limited. Without the wastegate you can build and build boost until you damage the turbo or the engine. If you are hearing a leak at the wastegate and seeing oil, it may have malfunctioned. In theory if your over boost valve is working then you should be fine as it will step in and limit intake manifold pressure that is building beyond 12psi on account of the wastegate being bad. Still, I’d be more concerned about getting that wastegate fixed ASAP than I would be with a leaking over boost balance.
 
Ahhh OK thanks you guys! Yea I will get that wastegate ordered asap. I just got my boost gauge today too. In this pic from Growler, is the line I highlighted green the correct one to install the T? Also the red arrow is where oil is coming from. I'll take a picture of my actual wastegate when I get another chance
 
Ignore the green vacuum lines, the pink boost lines are what you want when you're adding a boost gauge.

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sk66 said:
...my guess is it's blown if you can hear air coming from it.. And I would guess that means it's also causing the pop-off to blow when driving because it's not limiting the boost to a lower level.
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^this
 
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