Do These Exhaust Mounts Need Replacing

[MakaveliX]

Sorry if this is posted in the wrong section.

So there was an annoying loud rattle when in reverse or low revs. Took it to the garage and they said the exhaust mounts needed lubrication, so I did so with a silicone lubricant which has now fixed the rattle completely.

I took some photos of the two mounts and want to know whether they need replacing or not ? As one looks kinda squashed..

Thanks

[Krikkit]

Doesn't hurt, they're usually a few quid.

What I'd be worried about is the healthy crust going on - get it wire brushed and POR on it.

[Prinny]

I’d say they’re fine. The squashing is just how the exhaust mountings are fitting to the car.

They’re rubber (EPDM), and any rubber will cure (go stiff/brittle) over time with heat cycles. If you pull down on the exhaust to stretch them and lots of micro-cracks appear on the surface, then they’re degrading, and will need eventual replacement. If the cracks are visible without stretching, or if there’s no longer any flex/elastomeric properties left & they’re therefore brittle, then they need replacing, or they’ll snap at some point & drop your exhaust on the road.

You don’t say how old the car is, but if it’s <10, I wouldn’t worry for a few years yet. Just ask your friendly MOT tester each year as to condition & replace when they recommend.

[MakaveliX]

Krikkit said:

Doesn't hurt, they're usually a few quid.

What I'd be worried about is the healthy crust going on - get it wire brushed and POR on it.

Thanks guys.
Sorry but what is POR ? Also will any of these do for the rust?
https://www.halfords.com/search?q=wire+brush

Will a wire brush remove the rust if so why is that necessary ?
Thanks

I do have Lithium Grease and Silicone Lubricant at home.

Edited by MakaveliX on Tuesday 21st December 18:59

[Turkey]

MakaveliX said:

Sorry if this is posted in the wrong section.

So there was an annoying loud rattle when in reverse or low revs. Took it to the garage and they said the exhaust mounts needed lubrication, so I did so with a silicone lubricant which has now fixed the rattle completely.

I took some photos of the two mounts and want to know whether they need replacing or not ? As one looks kinda squashed..

Thanks

They look fine to me, no real stretch in them by the look of it, and they look to be quite a loose support in the first place, allowing quite a bit of motion by design. However, in your first picture, is that a metal bracket touching the exhaust on the bottom left? If so, it could cause a knock.

Edited by Turkey on Wednesday 22 December 01:14

[MakaveliX]

Turkey said:

They look fine to me, no real stretch in them by the look of it, and they look to be quite a loose support in the first place, allowing quite a bit of motion by design. However, in your first picture, is that a metal bracket touching the exhaust on the bottom left? If so, it could cause a knock.

Edited by Turkey on Wednesday 22 December 01:14

Thanks for the info. It's not touching no, just looks like that on the photo.

How many rubber exhaust mounts do most cars have ? Mine seems to have two.,

[Turkey]

It varies depending on the car. I would hazard a guess at most cars having at least 4, two or more on the backbox and two in the centre area.

You can try wobbling the exhaust I guess to find out where it is knocking. Mine knocked when I fitted a new centre section, drove me mad. The original exhaust was one piece, and the new centre section would not line up the same, as it twisted due to being clamped and not one solid piece of metal all the way along, it twisted inside the clamps due to gravity. I fitted a silicone rubber pad to stop it (silicone is good to a couple of hundred celsius so okay to touch on the lower temperature parts of the exhaust).

[MakaveliX]

Turkey said:

It varies depending on the car. I would hazard a guess at most cars having at least 4, two or more on the backbox and two in the centre area.

You can try wobbling the exhaust I guess to find out where it is knocking..

I'll have a look later but I could only see two, one right at the back, then one in the middle of the car towards the drivers side. As I said the rattling has stopped so I'm happy with that.

[E-bmw]

As has been said above, they are fine, the rust under them is distorting them slightly, remove, clean, lubricate & replace, then forget them.