300tdi whistle on acceleration

WreckITFrank

WreckITFrank

Technical Excellence Contributor
have a 300tdi that was lightly refreshed with new hoses, coolant, timing, used turbo, water pump, pulleys, and a few other things. Runs great, no leaks, seems like no loss of power. on acceleration (even at really slow speeds) I hear a pretty loud whistle that seems to follow along with the turbo, but louder. Definitely coming from left front, but cant figure it. I pulled the IC line off the turbo, and put about 15psi of pressurized air in and sprayed all the lines to look for bubbles, but i don't see or hear anything. i do hear a slight woosh sound when i let off the air hose, but it seems to be in the manifold and not the IC or line. Any ideas?
 
J

John Z

Well-known member
I had this happen to me and it was the inlet tube. The line that's used for the pcv wasn't connected behind the block. Once I connected it it went back to normal
 
J

John Z

Well-known member
Was there ever an outcome? Was it that hose? I only ask because if it was something else, could be good for me to know for future reference
 
RBBailey

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
I had something like this that I could swear had nothing to do with a leak along the turbo in/out because I had carefully seated and tightened everything, and there was no sign of anything loose.... it was a leak somewhere along the turbo in/out. If I remember correctly, it was the fresh air intake that was 100% secure, but there was just... barely.... enough... to allow the whistle. Once I reseated the hose, then really tightened down the clamp, it solved the issue.
 
WreckITFrank

WreckITFrank

Technical Excellence Contributor
RBBailey said:
I had something like this that I could swear had nothing to do with a leak along the turbo in/out because I had carefully seated and tightened everything, and there was no sign of anything loose.... it was a leak somewhere along the turbo in/out. If I remember correctly, it was the fresh air intake that was 100% secure, but there was just... barely.... enough... to allow the whistle. Once I reseated the hose, then really tightened down the clamp, it solved the issue.
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I'm almost certain it's resolved and that's exactly what I did. The secondary whistle seems to be gone, and I now just have a loud turbo spool, or so it seems. This is my first 300, so unsure if it's normal or not. @John Z put me on the right path and @RBBailey I think nailed it. I was too concerned with post turbo I guess.
 
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MountainD

MountainD

Technical Excellence Contributor
You want to hear turbo spool. At least I sure did with both the 200’s and cummins. And I think it’s a cool sound. Soulds like sheer rpm…
 
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WreckITFrank

WreckITFrank

Technical Excellence Contributor
hillstrubl said:
I have the same issue (that I texted you about a while back Frank) and my lazy ass still hasn't looked at the inlet hoses.
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It's back. So unresolved. Maybe but the same, but hard to hear as I need a passenger to help diagnose. Maybe just a noisy turbo... But I'm not yet sold. Runs good, so hard to tell if I need to take action, but the hoses could all use replacement from the fender on in.
 
MountainD

MountainD

Technical Excellence Contributor
That whistle is definitely not what I was referring too! Good job on recording it. Just curious--how can you tell that is from the Turbo? (Just curious on that...)

If it is from the turbo, the only thing I could think of that could provide a consistent high pitched squeal within the turbo itself would be the impeller bearing not getting the required oil supply that lubricates/cools it. Is that system free to fluid flow?

Otherwise, I would suspect from a leak and/or not the turbo at all---I have had aerodynamic whistles. Does this happen at a standstill as well, even under throttle? If you needed to simulate load without wind to diagnose, a Dyno would sure be helpful as they you could remove the hood and pinpoint where it is coming from in a stationary situation.
 
Angus

Angus

Well-known member
From the outside, it sounds like a very high pitched mechanical sqeek, but only at a specific boost range. Louder than the engine, and much louder than the turbo whine.
 
WreckITFrank

WreckITFrank

Technical Excellence Contributor
@Angus rode passenger to help me identify it. as stated, it's a different tone but eventually merges in with the turbo spool. this turbo is the replacement, meaning the one prior was replaced where the issue persisted. this sound is loud at very low speed, so likely not enough boost but def can be recreated with perfect speed/rpm.
 
M

Mirrajumper

Well-known member
4 thoughts:

**I had a whistle when the breather valve was funky. The larger hose that attaches to the top and is routed behind the cylinder head was “0ld and oil soaked”. I have run it to atmosphere and it makes the noise. I have run it with a new hose without noise.
** I also had to address the noise when using the alisport hoses. They are stiffer and don’t seal as well without really snugging up the clamps.
** what condition is the hose in that connects to the injection pump?
** when my cylinder head was off I found that the exhaust manifold wasn’t perfect. A gasket and new studs ensured a leak free fit.
0BACAB45-DF32-47CF-AFD7-CBDBA869D1CD.jpeg
 
WreckITFrank

WreckITFrank

Technical Excellence Contributor
Every hose on the 300tdi is new, and silicone from Stoney Racing. They all fit well except the turbo inlet 90, that would not stay on. I checked all clamps and did pump some air through what I could, but that breather is a shitpart or whatever non geniune that LRdirect had. I dont think they had OEM, just gen or junk. I could replace it for the hell of it and see.
 
MountainD

MountainD

Technical Excellence Contributor
An airleak causing a whistle does seem like a very real possibility. It's basically how we whistle after all...
 
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