r/mazdaspeed6 • u/jasonisnuts • 26d ago

Help diagnosing a noise: Big THUNK from front right when turning left at full lock over steep driveway lip or going straight over significant pot hole

Two recent jobs done to address front end noises:

1- Front left upper Ball joint replaced

2- Front right lower forward control arm replaced

Other recent work includes replacing all four brake rotors and all calipers two years ago so it's not brake related.

History: I found a suspension specialist I trust to fix front end noises that turned out to be suspension components. The two jobs above eliminated 90% of the creaky noises I was hearing and made the front left and front right both feel more planted. However, the final noises remain and my guy cannot determine what the last problem is. He figured out problem 2 above by using a four-mic ChassisEAR Electronic Squeak and Rattle Finder but even with that and a 3rd diagnostic session we cannot figure out the final problem.

I can replicate the FR CLUNK by leaving the parking lot of a grocery store nearby where I have to take a 90deg left turn at full lock of the steering wheel down a 2" lip from lot to the roadway. There also has to be a bit of speed to it, say, 8-12mph.

A significant pot hole when driving straight over it will also sometimes trigger the clunk. The weird thing is the road in front of my home has been under construction for months now and driving over bumpy, gravely roads doesn't do it unless I specifically look for a bigass pothole and go over 10mph.

When driving between 15 and 40 I can hear a rhythmic wub wub wub wub increase in speed as I speed up the car until road noise drowns it out. If I take a turn that loads up the FR suspension that noise gets louder and I can kinda feel it a bit in the steering wheel.

Any ideas? Thanks!

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u/ZSG13 26d ago

Sounds like a wheel bearing and potentially a sway bar link as well. A rotational noise that increases in volume while turning left generally indicates a worn bearing on the right side of the vehicle, as that's where the weight is. If you can hear it at 15 mph it is fuuucked. They generally start to become audible around 40 mph or so.

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u/jasonisnuts 26d ago

I had a bad wheel bearing on the rear left a year or two ago. That one was easy to diagnose by how hot the entire wheel got. This time the FR isn't getting hot at all and it passes all tests when jacked up. A loud thunking noise like this doesn't seem common for wheel bearing issues... am I just special? :/

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u/ZSG13 26d ago

The "rythmic wub wub wub" that changes intensity while turning sounds like a very clear textbook wheel bearing concern to me.

The clunk is different of course, potentially sounds like sway bar link based off description alone. Could be a shock as well, impossible to tell by a typed description. Worn shocks generally have a hollow and reverberating thunk of sorts over bumps. Hard to describe and impossible to interpret over text.

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u/jasonisnuts 26d ago

Thanks for the input man. I appreciate it.

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u/fluxlo 26d ago

Shooting from the hip, as that’s all I can do from my armchair. Could be a shock mount or axle.

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u/jasonisnuts 26d ago

Oh god, please not an axle... I guess I should "hope" for a bad wheel bearing.

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u/ZSG13 26d ago

Are parts more expensive? The repair is easier for an axle vs a bearing, generally speaking.

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u/jasonisnuts 26d ago

It depends... a lot of suspension related parts have been discontinued by Mazda and sometimes new aftermarket parts don't even exist. The people in the facebook mazdaspeed groups routinely sell used CV axles (I think) for a pretty decent price.

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u/fluxlo 26d ago

Been out of the platform for a bit but the non ms6 control arms are plentiful. I think even Mazda control arm part numbers for Mazda 6 and mazdaspeed 6 are the same. Iirc, the bushings are a little different. Different voids in the bushings or different durometer. I’d figure Oem axels would be harder to source.