Knocking sound at low RPM?

[GCATX]

Yeah, I plan to bring it in on Monday and see what they think. It's strange, for sure.

I thought it was something in that area too, but when I listen to it in real-time it sounds like it's coming from the engine itself. Very, very strange noise. I've also noticed some rattle noise at 2-3K rpm under acceleration. Some of it is drowned out because of the fake exhaust noise. I'll find out what the dealer thinks!

A year or two ago someone posted a similar sound and it was mud hitting the fan, as I recall. Real deep sound like a drum. Yours reminded me of it. Best of luck.

 

[Forumr]

A year or two ago someone posted a similar sound and it was mud hitting the fan, as I recall. Real deep sound like a drum. Yours reminded me of it. Best of luck.

Well I certainly appreciate the input -- I will have to take a closer look at the fan.

FWIW, I did take it to the dealer this morning (apparently they have a 10 day backlog and are still taking appointments... SMH) just to see what they thought and the tech didn't have a clue. His first inclination was turbo related, but wasn't sure. Have something scheduled to bring it in on Saturday. Won't be touched for 7+ days after though. Kind of crazy.

 

[Forumr]

Not sure if anyone is following - but I figure it may help someone down the road.

I took it to the local Ford dealer and they had it for a few days. They've heard the sound and believe it's the electronics on the turbos causing the wastegate to do whatever it does. The master tech described it as a "thunk" in light load conditions. He said it's "normal" and there was a TSB (I can't remember for sure if TSB or something similar) that said nothing needed to be done.

He also mentioned he's heard a couple here lately after the 21B10 update. Not sure how that would affect turbos at all, but he seemed to think there was some reason for it. The service advisor handed me a sheet of paper, but I'll have to go find it. I asked that they put it in the notes, just in case. I should note -- I know it's not wastegate rattle like when they are cold. This is after the engine has been warmed up and held at 750-800 RPM or so.

Would be interested to hear @FordTechOne thinks. Every other dealer is 1 month out before they can even look at the thing.

 

[Forumr]

I took it to another dealer after about a week because it just didn't seem right. After 3.5 weeks of sitting there waiting, it sounds like the truck is in need of a new turbo.

There are several other small things wrong that they wanted to fix as well, but said it's definitely a bad turbo. Waiting to hear on ETA, but hopefully the Raptor will be up and running again in a few days.

 

[FordTechOne]

I took it to another dealer after about a week because it just didn't seem right. After 3.5 weeks of sitting there waiting, it sounds like the truck is in need of a new turbo.

There are several other small things wrong that they wanted to fix as well, but said it's definitely a bad turbo. Waiting to hear on ETA, but hopefully the Raptor will be up and running again in a few days.

It sounds like they found an issue with the wastegate mechanism on the turbo side. The actuator can be serviced separately, but an issue with the wastegate itself requires replacement of the unit.

 

[Forumr]

It sounds like they found an issue with the wastegate mechanism on the turbo side. The actuator can be serviced separately, but an issue with the wastegate itself requires replacement of the unit.

That's what I had thought too. I was supposed to pick it up a couple days ago but the service manager called and said after getting it warm again, the exact same noise was going on. I think he's off yesterday and today, but it will be interesting to see what they find out.

 

[Forumr]

@FordTechOne - got the truck back last night. The service advisor (who has been an excellent communicator through this whole process) said "we didn't fix it, but I have more parts coming that are on backorder." So in the meantime, they are letting me drive it.

They replaced the left turbo (passenger side) and the noise remained. The technician did say he found excess turbo shaft play and leaking oil, so it probably didn't hurt to replace. They moved it around the shop trying to pull different opinions in on what could be causing the noise. Apparently, and I suppose it remains to be seen when they put it on, the catalytic converter on that bank is causing small "backfire-like" noises in the exhaust/engine. So the next step is to replace the cat when they come back in stock - thinks it'll be a month or more. First I've heard of an issue like this being caused by the cat, but what do I know?

Continuing to update this in the hope that maybe it helps someone else out one day... or I just like to ramble.

 

[FordTechOne]

@FordTechOne - got the truck back last night. The service advisor (who has been an excellent communicator through this whole process) said "we didn't fix it, but I have more parts coming that are on backorder." So in the meantime, they are letting me drive it.

They replaced the left turbo (passenger side) and the noise remained. The technician did say he found excess turbo shaft play and leaking oil, so it probably didn't hurt to replace. They moved it around the shop trying to pull different opinions in on what could be causing the noise. Apparently, and I suppose it remains to be seen when they put it on, the catalytic converter on that bank is causing small "backfire-like" noises in the exhaust/engine. So the next step is to replace the cat when they come back in stock - thinks it'll be a month or more. First I've heard of an issue like this being caused by the cat, but what do I know?

Continuing to update this in the hope that maybe it helps someone else out one day... or I just like to ramble.

Some movement in the turbo shaft is normal; these are journal bearing turbos, not ball bearing. I highly doubt the turbo was actually bad. Hopefully they have the diagnosis right this time, a damaged catalyst can make noise if the substrate is loose within the housing.

 

[Win Seeker]

@FordTechOne - got the truck back last night. The service advisor (who has been an excellent communicator through this whole process) said "we didn't fix it, but I have more parts coming that are on backorder." So in the meantime, they are letting me drive it.

They replaced the left turbo (passenger side) and the noise remained. The technician did say he found excess turbo shaft play and leaking oil, so it probably didn't hurt to replace. They moved it around the shop trying to pull different opinions in on what could be causing the noise. Apparently, and I suppose it remains to be seen when they put it on, the catalytic converter on that bank is causing small "backfire-like" noises in the exhaust/engine. So the next step is to replace the cat when they come back in stock - thinks it'll be a month or more. First I've heard of an issue like this being caused by the cat, but what do I know?

Continuing to update this in the hope that maybe it helps someone else out one day... or I just like to ramble.

Does the noise happen in only Drive and Reverse, but not Neutral and Park? There's a similar thread https://www.fordraptorforum.com/threads/tapping-sound.65140/page-3 that sounds pretty similar to what you're experiencing. Since replacing your Passenger Turbo has the dealer provided any remedy?

 

[Forumr]

Nothing fixed after the turbo was replaced. They waited on a catalytic converter (thinking it was damaged or something), replaced it and got the truck back this afternoon. Noise still present.

Not a clue what the deal is with it. The thread linked above sounds like maybe, but I don't know. You can feel the physical impact of the thumping noise I'm hearing on the passenger's side turbo. Not sure where to go from here...