Can Wastegate Rattle While Under Boost?

[Jerome10]

Still trying to pinpoint what sounds like a heat shield rattle around 1800rpm and light to moderate throttle. Sometimes I think it sounds like near the exhaust and others like it’s in the engine compartment.

Listening at idle today I’m hearing a metallic rattle towards the engine area. I’m assuming this is likely wastegate related.

Then on an incline I kept the truck in a high gear in manual mode and applied throttle. Boost gauge showed positive boost to engine, but I could still hear that metallic rattle around 1800 rpm (again not sure if engine or exhaust area).

My limited understanding of the wastegate function is that if the truck is providing boost that the waste gates should be completely closed, correct? And if completely closed there wouldn’t be any slack or slop that could rattle?

or is it possible that even under boost you can get wastegate rattle? Or actuator rattle?

I’ve asked dealer to look twice and been told it’s wastegate. I’m very skeptical that’s the issue so hoping if I can narrow things down I can say “it’s the resonator or heat exchanger” or i can accept that I do actually have wastegate rattle, even as awful and can of marbles as it sounds… and that it’s “normal” to sound like junk.

edit: don’t think it’s bell housing, which has a TSB for other engines but excludes powerboost

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[SALEEN961]

The wastegates are almost never completely open or closed, they are usually somewhere in between those positions and they can easily rattle under boost. Mine rattle enough to trigger knock retard and pre-ignition FMEM because the knock sensors hear them loud and clear. My truck currently has about 25K on it, but the rattle started years ago at a much lower mileage.

 

[Les_Garten]

I don't know about Fords, I don't have one yet.

But I have a 2002 Land Cruiser that does exactly what you are talking about until it warms up quite a bit.

It's a heat shield on the exhaust near the O2 sensors. Been meanin' to put a hose clamp on it.

That's all I got!

p.s. I have a Porsche 930 that started out with original wastegate and Blow off valves and I changed them out to Tials. They never made a noise that sounded like a heat shield rattle.

Myabe some clicking, that's about it. Much simpler system obviously, 1985 vs 2025

 

[Jerome10]

The wastegates are almost never completely open or closed, they are usually somewhere in between those positions and they can easily rattle under boost. Mine rattle enough to trigger knock retard and pre-ignition FMEM because the knock sensors hear them loud and clear. My truck currently has about 25K on it, but the rattle started years ago at a much lower mileage.

this is helpful. Appreciate the response. What is FMEM?

If they can rattle off boost and on boost then thinking very possible they’re my culprit.

 

[Jerome10]

I don't know about Fords, I don't have one yet.

But I have a 2002 Land Cruiser that does exactly what you are talking about until it warms up quite a bit.

It's a heat shield on the exhaust near the O2 sensors. Been meanin' to put a hose clamp on it.

That's all I got!

p.s. I have a Porsche 930 that started out with original wastegate and Blow off valves and I changed them out to Tials. They never made a noise that sounded like a heat shield rattle.

Myabe some clicking, that's about it. Much simpler system obviously, 1985 vs 2025

oh man I just spent the other day crawling completely under the truck, engine compartment, everything. I don’t think it’s any heat shield. I’ve banged on hot and cold exhaust and heat exchanger. I think they’re all ok.

Im growing more certain it is either wastegates or timing related (chain? VCT solenoid?). No rattle on cold start so I don’t think it’s the phasers.

I have to say I do not appreciate the bucket of marbles noise of wastegates would be considered “normal”. Sounds terrible. Ford should be able to eliminate that I’d think. Lexus turbos. BMW turbos. I’ve never heard this in my life till this truck. Trans? It sounds more in front of me than below me when I hear the marbles.

 

[SALEEN961]

this is helpful. Appreciate the response. What is FMEM?

If they can rattle off boost and on boost then thinking very possible they’re my culprit.

Failure mode effects management, it's just the phrase used in the PCM instead of limp mode. In my case, pre-ignition FMEM shows up as an active limiter when my truck goes into limp mode because of excessive pre-ignition being reported by the knock sensors. If you think the noise is bad on our trucks, you should hear some of the Mercedes M278 engines at startup. Between badly worn wastegates and failed camshaft phasers, the M278 can get really loud.

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