Non-Caterham issue.

[magnusfeuer]

Sorry for polluting the forum with a Nissan 350Z question, but I am stumped.

2004 Nissan 350Z, 6 speed belonging to my wife 53Kmiles. About 5K miles ago it started developing a thumping sound that starts when turning slightly (lane change type) at speeds above 20 mph. The thumping got worse and eventually was present while driving straight. It sounded like a flat spot on the tires.

Since the tires were beginning to look a little beat, I had them all replaced yesterday. A wheel alignment was done as well. The thumping is still there while turning, although it is gone while driving straight.

It is up front, but I cannot feel anything in the wheel. The thumping is present in and out of gear, with clutch up and down, and has a cadence tied to the rotation of the wheel.

I checked the bearings for play a while back, and they are tight and nice.

Any ideas?

/Magnus F.

PS. It's for sale in case anybody want to own a fun car with an attached mystery.

[Doug Liedblad]

Power steering pump???

From a Nissan forum:

'I had the same problem and took it back to the dealership. Turned out to be a bolt of the frame rubbing against the engine mount bracket. It was actually wearing away the engine mount bracket.'

[Yosemite]

I would suggest you check your CV Joints. This is a typical noise they make under load or when turning, they are either dry of have a rough spot on one of the bearings.

Yosemite

[Doug Liedblad]

Are not 350Zs RWD??

A Google search on 350Z thumping turns up several references. Mostly to tire wear or unknown causes.

It may be THADTS.

Doug

[magnusfeuer]

It's not tire wear. The old fronts had at least 20K on them and were still in OK condition. Evenly worn. The 350Z has a reputation of feathering (premature tire wear), which is accompanied by a roaring sound. This is something that I do not have.

I just came back from the tire shop where we put it on a lift. The front wheels are fine. No brake issues. No bearing issues. Lots of clearance everywhere.

I'll go to the Nissan dealer next.

/Magnus F.

[magnusfeuer]

Yosemite, the car is an RWD, and the noise is from the front.

/Magnus F.

[Mondo]

I have an infiniti G35 coupe... same drivetrain, basically 350z with a back seat. My front tires get noisy after the first 1000 miles or so (notice it most slowing from 20mph). Do like the car though.

Sorry, can't help you... just thought I'd add some useless,vaguely related, conversation;)

[MHKflyer52]

Look for a loose plastic pannel in the wheel wells or around the front spoiler. 20 mph is about the speed that the air flow will start to lift them if it is in the flow and loose.
Just a thought.

[athens7]

My Nissan mechanics suggest the compression rod bushings on the front suspension may be worn out. The compression rods must be replaced if this is the problem. They say this wear condition will lead to a knocking noise, and is a common issue on 2004 350Zs and G35s.

[magnusfeuer]

Thanks, Brad.

I'll have a look tonight and see if there is play in that part of the suspension.

/Magnus F.

[magnusfeuer]

The 350Z went into the dealer today after I checked the front suspension and found no play.

They tried to blame it on the (brand new) tires first, but I asked them to put on a different set of wheels and take it for another spin. After some more fault searching, they found that it was the LF wheel bearing. They are replacing it right now, and we'll see if that fixes it.

/Magnus F.