Hey guys!

 

Recently new 300zx owner, and am esctatic with the car!

 

Literally the only issue with the car I bought is a knocking in the rear quarter passenger side. It sounds like it's behind one of the quarter panels, and definitely sounds like it's internal, like it was the speaker or something similar.

 

I've not managed to track it down, and I don't think it's suspension related as the car has only done 40,000 miles and the suspension is very solid, no play and doesn't feel like there is anything up with it. Is there anything else that might be known to cause it?

Take the rear plastic panels out to have a look. There is very little in the pass rear quarter, the boot cable runs past the petrol flap opener (same cable) does both, you might have a loose bracket. The boot hatch may need adjusting, 3 bolts, when you go over bumps it can knock. There is a breather box down in the rear arch cavity, then there is a polystyrene tray for holding bits and bobs, you may have something in that rolling around.

 

Apart from that, there isnt really anything in the internal rear pass quarter. Then you get to the suspension parts and bushes(external)

 

HTH

Graham

We had the panels off to have a look yesterday and couldn't spot anything, although the only thing on the list that I saw was the breather box so I might have to take another look!

The breather box is plastic, so they may rattle rather than a knock.

Although you say its had new suspension, check the drop links on the anti roll bar, upper camber arms and the lower arms for play. Having new struts and springs alone, with no other new parts can cause stress on the oem bushes, also if its been lowered and nothing else modified then the same thing may occur. Being Tein adjustable set up, i would definitely look into other suspension parts.

Does it happen mainly going over bumps in the road, or is it constant?

 

Dont disregard the rear hatch, if the catch is loose or needs adjusting then that will cause knocking and it will sound internal.

 

Graham

Edited May 3, 201015 yr by groover

It happens pretty much constantly, even on the smallest bumps. It sounds like the bump of the road goes through it, and it sounds like plastic rattling around.

 

I know what suspension problems sound like, and i'm pretty sure it's not that. It sounds very clear as if it's inside the car.

Then i would check the rear hatch, at least you can eliminate it if that doesnt cure the problem. could be an exhaust rubber or bracket, worth looking at.

Honestly, it's more of a rattle than a knock! I'll check the boot hatch, but i'm pretty sure it's not coming from there. I had a friend with his head in the back as I drove to try to pinpoint the sound though.

 

I'll deffo take a look at the hatch, but it did apparently sound like it was coming from the fuel cap area.

 

Thanks for the advice dude :)

Took it to a mechanic friend of mine, and he said it's most likely the bush at the top of the shock has worn, so will be a very cheap fix if this is the case!