OK so only one of my coilovers seems to have the problem (the front passenger side one). My set of stance coilovers were bought brand new in february and only have 5,000 miles on them. Here's what happend:

One day last month I was going about 35mph on a road I hadn't been on before and there was a sharp dip in the road that was hard to see and it caused my car to bottom out. This was about a month ago. The front passenger side coilover now makes creaking, lurching and spring like noises when driving over bumps and when turning the steering wheel at low speeds and also when hitting the brakes to slow to a stop light. When the car is parked you can pop the hood and pull on the car on the passenger side engine bay and it will make the creaking noise as well. If you drive the car down a road that has bumps that hit the drivers side wheels but is smooth where the passenger side wheels are, there will be no sounds coming from the suspension at all. I've taken the front passenger side wheel off to check it out and all bolts seem tight. I've checked the 10mm top bolts holding the coilover to the body in the engine bay as well. Nothing seems loose - but it sounds loose. Also, performance doesnt seem to be affected, the car rides good still. The noises are just loud and really annoying and it sounds like my car is broken. Any idea what it is or what I can do? All of the other coilovers on the car seem fine and they don't make any noises.

 

Well, based on that, it sounds like your strut is blown. However, if your passenger side is riding the same, I would assume that not to be the problem. But that's what it sounds like.

 

Really sounds like the LCA bushing let go , check it out

 

I had a set of blown stance coilovers on my 240 and they dont sound like this, those made noise over every bump. My problem coilover doesnt make noise at highway speeds and it makes noise when the wieght of the car shifts from front to back as well, such as when braking for a red light. The blown coilovers didnt do that.

 

https://my350z.com/forum/8293650-post23.html look for this

 

Interesting, I will look!

 

It wasnt the bushings, and it wasn't the coilover, but what you said actually helped me look at it in a new way to figure out what it was. The large front underbrace that is in the shape of bat wings was about 90% tight in 4 or 5 places, and one of these bolts was shared with a control arm mount so tighting these 4 or 5 bolts all the way 100% completley solved the problem and the suspension is now silent!

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That could definitely cause that noise, too much chassis flex. Good job man,

 

Thank you sir, case closed!