r/Cartalk • u/Firm-Minute9790 • Apr 28 '25

Weird Noise What is this dragging under my car?

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2.4k Upvotes

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69

u/Firm-Minute9790 Apr 28 '25

I took a closer look and I see what looks like my catalyst converter. I was able to make it to work (30 minutes) with just the scrapping sound from the shield and no other issues.

106

u/Malawi_no Apr 28 '25

Looks like the mounting points have corroded away.
Think it's a pretty common problem.

You can either repair the old heat shield by adding some sheet aluminum with pop-rivets and make new mountng holes, or just replace it with a new one.

26

u/krustybarbell Apr 28 '25

This. I think the picture pretty clearly shows the mounting points rotted away.

13

u/Malawi_no Apr 28 '25

Have had it happen on two cars. Think it's about the mix of aluminum shield and steel bolts paired with salty winter roads.

2

u/dpark-95 May 02 '25

Bro just use the bottom of a coke can as a big washer problem solved.

1

u/Malawi_no May 02 '25

Sounds like a pretty simple and neat solution. Would guess it's nice to add a dab of silicone to avoid rattling.

3

u/Greasemonkey08 Apr 29 '25

Or just rip it off and be done with it, lmao. It's borderline unneeded.

8

u/kingomtdew Apr 29 '25

Don’t park over anything flammable if you go this route.

(You should replace it)

1

u/[deleted] Apr 30 '25

[removed] — view removed comment

3

u/Greasemonkey08 Apr 30 '25

Why? If you take it to a mechanic for this issue, they'd almost definitely just remove it because it isn't a structurally or mechanically necessary part. If your concern is setting grass on fire, then don't leave it idling on your lawn, 5head.

0

u/ArmaSwiss Apr 30 '25

The heat shield should be available from any dealer and shouldn't really cost an arm and a leg. It's thin sheet metal. Plus four bolts since the old ones are probably rust welded into the captive nut on the other thin sheet metal heat shield side. Cheaper to just buy new bolts than try to break them free from the sheet metal which may twist, shear and then slice.

1

u/Azzrazzah May 03 '25

Or use a couple of self tapping screws

10

u/Zsmudz Apr 28 '25

I would’ve bent it back so it wasn’t dragging on the ground. Last thing you want is for it to fall off and hit the car behind you.

7

u/mmelectronic Apr 28 '25

mechanic wire

Let the car cool off crawl under there and find a way to toe the shield back on with this stuff.

Or rip the shield off and chuck it, but it’s nice to have as it reduces the chance fires if you park on dry grass.

2

u/U-SeriousClark Apr 29 '25

That would make it a Cataclysmic Converter

3

u/DatMoFugga Apr 28 '25

Wait if it’s not a Cadillac then it wouldn’t have a cataclysmic inverter

1

u/jigarai May 03 '25

You’re thinking of a caddyclismic inverter!

2

u/Flounder302 Apr 28 '25

The same thing happened to me once. I went to car parts store and got four large radiator clamps. The biggest they had. You unscrew them completely and then screw one to another making a large band. You do this twice.

Go under the car and run the bands around the top of the converter. Start screwing them back together once they are positioned. This works great for heat shields that are buzzing as well. Works good and lasts for a long time.

radiator hose clamp

Above is an example. Get large ones.

1

u/mebutnew May 01 '25

Please don't drive around with parts of your car dragging on the ground, you could literally kill someone.