What is this metal thing hanging under my car?

mazda
protege

#1

It’s not making any weird noises- it’s not dragging on the ground… yet. Just noticed it today when I was walking to my car from a far distance… help!


#2

Looks like an exhaust heat shield coming loose.

Bring it to a shop, and see if can be reattached, or it may have to be removed.

Tester


#3

If it is the heat shield, the only downside I have ever heard for having it removed is you can start grass fires driving in a field.


#4

I can’t tell what it is, but whatever it is I recommend you consider it a safety issue until you get it checked out ASAP. If you have part of a subframe hanging down, perhaps due to rot, you could have a serious issue there.


#5

Looks more like a heat shield between the exhaust pipe and the floor (to keep heat out of the cabin).


#6

I am with TSM I can’t tell what it is from the poor picture. Hey, Danilenae do you have a friend who can lay on the ground and see if it is part of the exhaust system?


#7

Here is a picture from the other side of the car- this one is a little better:

I know nothing about cars. And I have so many obligations which require driving this weekend… Was hoping this is something I can wait until Monday to bring into the shop… and I don’t know anyone who knows crap about cars. I could have someone crawl under, but I doubt they could tell me what other parts it’s connected to.

Thanks for the feedback, guys!


#8

…I live in Minnesota… hence all that rust! And she’s old- born in 2000. :slight_smile:


#9

It definitely looks like something to do with the exhaust system. I wouldn’t do much driving until you at least get a shop to put the car on a lift & inspect the situation for you. If the exhaust system leaks it can cause engine problems, but worse, it can cause unhealthy to breath exhaust gas to leak into the passenger compartment. Depending on what it is, when they get it on the lift they might able to effect a quick fix so you can drive this weekend, then you can bring it back later for a proper fix. Best of luck.


#10

A heat shield is just a piece of sheet metal (stainless) attached above the exhaust to block the high temps from the exhaust. It’s not dangerous but you don’t want to lose it either. With age and vibration they break away from the screws holding them in place. Just have a shop re-attach it again. Maybe grab onto it to see how loose it actually is so you don’t lose it on the road. The problem with stainless though is its hard to drill for new holes.


#11

That is an under-body heat shield to protect the floor from the exhaust pipe heat. A loose heat shield won’t cause an exhaust leak so don’t worry. A muffler shop might reattach it for pocket money.


#12

A loose heat shield could damage wiring, fuel lines, or brake lines in the process of breaking away and bouncing around under the car at freeway speeds.


#13

Well a well-intentioned but stupid friend tried to knock it off and now it’s hanging down much lower and is scraping the pavement when I go into driveways- so I’m bringing it into the auto shop first thing tomorrow morning and they’re going to remove it for me… woohoo. It’s only 4 blocks away too. I think I will bring it back to get it replaced next week when I get paid and have more $$$. I just hope there isn’t anything else damaged under there… Thanks everyone!


#14

Assuming it is a heat shield, and since your friend tried knocking it off I assume that’s been confirmed, I recommend not having it removed. cat converters get hot enough to ignite dry grass, which was a problem when they first came out before heat shields were installed, and you might regret it. A match flame burns at about 750F, and cat converters’ internals can easily exceed 800F. The ceramic substrate onto which the platinum-palladium (the catalyst) is deposited retains heat energy very well, just like that ceramic cooking vessel often used for baking (its name escapes me… I don’t cook). That heat dissipates as radiant heat energy directly out the surface of the canister.

In my state, the normal repair for a loose cat converter heat shield involves surrounding it with one or two large hose clamps from a hardware store and tightening it up. I’ve done it and it not only works, it passes the annual safety inspection. And those clamps last indefinitely even when subjected to the heat of a converter.


#15

Engineers and car companies do not decide to spend money on useless items, my suggestion would be to have it repaired properly. Not necessarily a dealer replacement, tack weld, hose clamps whatever :cat:


#16

To beat up that shield and remove it is a bad idea. You might find that a replacement costs more than $75 plus and hour of labor.

It should only take 10 minutes to install new fasteners to reattach it to the floor of the car.


#17

But it’s covered in rust and literally falling apart… I don’t think it should be reattached when it’s literally crumbling into rusty crumbs, should it?

I have to drive it around this weekend- then I can bus to work until next Friday payday then bring it back in for proper repairs. This is just a temporary thing this weekend thing, pretty much. And only about 50 miles this weekend total. Not all at once, either. 15 miles one way, 15 miles back- the next day 10 miles one way, 10 miles back- both trips with many hours inbetween departures.

I live in MN and it won’t be getting hot here (over 80 degrees) for another couple months so I think I can get by another week without the shield… I have to.

I don’t know anyone who can fix it up the way youre suggesting- I have no car savvy friends. I’m sure it’s cheaper to have someone who knows what they’re doing just crawl under there and tweak it, but I don’t know anyone like that- so I gotta go to the auto shop. :-/

I’ll post again if anything interesting happens.


#18

As suggested earlier, visit a muffler shop, these repairs are routine. Friends and others outside the repair field may not be able to correct this so easily.


#19

When it’s up on the lift, have the mechanic check for rust in other areas. With that much rust on the heat shield, it’s possible that your car has major rust damage and is becoming unsafe to drive.


#20

It might be dirty but it’s stainless so not rusting. It’s going to be 80 here in southern Minnesota today so just get it put back on.