Scraping noise from underneath car.

[soapy]

Hi all my first post for a while and my problem is whilst driving at speed along dipping country roads when i hit the inclines i get a metallic scraping noise from under the car.
I do not have an undertray neither has the car being fitted with mud flaps and looking underneath i can see nothing hanging down.
Any ideas anyone.:shrug:

[Amsca2]

wheel arch liners catching when suspension is laboured?

[RogerHeinz57]

There is a possibility that an exhaust heat shield has come adrift, sometimes hard to notice unless under the vehicle as it can only drop down as far as the exhaust. So maybe worth a look there.

[dad1uk]

There is a possibility that an exhaust heat shield has come adrift, sometimes hard to notice unless under the vehicle as it can only drop down as far as the exhaust. So maybe worth a look there.

I had this problem, there is, on mine (2.0 CDT Tourer), a heat shield under the gear stick area which on mine is held by 4 bolts. Two had pulled through the plate. I solved this by putting two large washers and refitting the bolts.

[klarzy]

It will be the bottom of the front sub frame bottoming out... the 75's suspension is quite soft and I get this a lot on local roads in the fens...

The ZT has firmer springs and does not do it on the same roads...

go slower or avoid the bumps is the answer

[soapy]

The wheel arch liners are all fine so is the exhaust heat shield as i had to do that on a previous ZT-T so i would have to agree with Klarzy that it is the subframe bottoming out i will obviously have to live with it.
Thanks for the reply's though.:}

[T-Cut]

It will be the bottom of the front sub frame bottoming out...

Yikes, you mean the subframe scrapes on the road?:eek:

TC

[klarzy]

Yikes, you mean the subframe scrapes on the road?:eek:

TC

Yep,
Soft springs, 15-16 in wheels and undulating roads... it happens...

17 inch wheels help, 18's are better, the firmest springs also do the trick...

I have no issue with my zt, 18's and a splitter with no rubbing unless I am really travelling over the bumps..

[Kennyeth]

Are your springs all good? you can have a broken spring and it might not show. They can break at the bottom (hidden) what`s the car like over speed bumps? especially at a big Asda S/mart.
My saloon scrapes metallic over some speed humps no matter how slow I take it.
Ken.

[klarzy]

Are your springs all good? you can have a broken spring and it might not show. They can break at the bottom (hidden) what`s the car like over speed bumps? especially at a big Asda S/mart.
My saloon scrapes metallic over some speed humps no matter how slow I take it.
Ken.

On my 75 new springs and shocks all round in the last 12 months, checked regularly...

The roads are like a roller coaster...

[Falcon Flyer]

I'm shocked if its actually the subframe scraping on the road when the suspension has bottomed out!

I've had similar noises, first it was the engine under tray missing some fasteners, and then the front mudflaps.

[klarzy]

I'm shocked if its actually the subframe scraping on the road when the suspension has bottomed out!

I've had similar noises, first it was the engine under tray missing some fasteners, and then the front mudflaps.

No undertray or mudflaps...

Paint missing from low points on sub frame...

trust me, i's scraping and I am not alone, just ask some of the folks who have visited me...:D

the fen roads have undulations and deep tyre ruts, so it does not shock me at all..

[EastPete]

I still have front mudflaps on my car, but they get shorter each year, as I trim back the 'frilly' bits they acquire at the bottom, as they scrape along our Fenland roads. I still have my undertray as well, complete with battle scars !

Pete

[Falcon Flyer]

Yep, I'm officially shocked then Pete! I know our cars run low to the ground but thankfully I haven't bottomed out that far yet. Btw I'm on 15" rims, but maybe the roads near me are in a better state of repair!

[chris75]

Isn't the overall diameter with tyres the same for all size wheels on a given car ? If not it would affect the overall gearing and speedo readings . Bigger wheels have thinner lower profile tyres :shrug:

[klarzy]

Isn't the overall diameter with tyres the same for all size wheels on a given car ? If not it would affect the overall gearing and speedo readings . Bigger wheels have thinner lower profile tyres :shrug:

Larger radius rims means less deflection or squashing under load, that's why 17's corner better than 15's... Bigger rubber means more squish.