What is that flimsy cardboard cover under my car engine? Do I need it?

I’m trying to take off my alternator. I crawl underneath my car and this flimsy, crumbly, soggy, black cardboardish cover is blocking my access. I can’t figure out how to take it off because its partially held on by some odd connector I can’t figure out how to unscrew/pull out. I just want to rip this thing apart. Do I need it? Is it there to protect the parts under my hood, or to catch leaking fluids from under my hood(which is what its doing now)? I can’t find any pictures of it on Google so I can’t imaging its all that important?

It sounds like you’re talking about the stone protector. It’s there to keep rocks and miscellaneous road debris from flying up and hitting the engine and stuff.

Do you need it? I dunno, but that’s the reason it’s there.

It’s probably, as kunilou said, just a random protector to keep road crap from hitting your engine. It probably also helps with wind resistance. If you look around the edge there’s probably some plastic rivets. There’s a few styles of them. Some of them you have to pry them out a bit, then push them back in, while keeping then center portion raised and then pull them all the way out. When you put them back in, you insert them all the way, then push the center post in to engage them. They look like this or this. You can tell if it’s this style because you’ll be able to see the little ‘dot’ in the center.

Some look more like this or this and you can just pry those out and push them back in when you’re done if you don’t ruin them.
Then, there’s a style which for some reason I thought was called sacrificial but I don’t recall for sure, that’s designed to be ruined when you pull them out, but I don’t think you’ll run into them under a car. The only place I’ve seen them was holding the trim on an A piller.

ETA, if it’s the first type, they’re called nylon rivets. I’d bet if you googled something along the line of ‘removing nylon rivets’ you’d probably come up with plenty of ways to do it.

Any chance the OP is referring to the head gasket?

I don’t think so since he makes the distinction between under the hood and under the car.

I_Know_Nothing, what make, model and year are we talking about here?

The stone protector was hanging down on my car. I took it to the garage and they just removed it, said it wasn’t necessary.

If it’s underneath the engine compartment it’s called a gravel shield. Most are made of plastic, which as you can imagine is superior to the fiberboard(?) type described in the OP. If it’s on the side, say between the wheel well and the “front” of the engine (where the pulleys are), I’m not sure what the term is. In either case, it’s as kunilou stated, to prevent debris from getting into moving parts and possibly derailing a belt or causing other damage. The ones underneath can also help minimize damage from, say, scraping over a parking space curb.

Apparently the manufacturers consider it worthwhile – it’s not something they can tout to customers to justify a higher price for the car, but like any part that goes on tens (or hundreds) of thousands of vehicles, it becomes a noticeable cost of production. Practically speaking, I can’t say I’ve ever seen a problem from a missing gravel shield in 38 years of working on cars. I always reinstall them if they’re not badly torn up, but I wouldn’t lose any sleep over leaving one off.

ETA: As for the fasteners, different types are used. They’re not a big challenge if you’re used to them, but some can be perplexing the first time you run into them.

My Jeep had one as described in the OP - kind of a heavy cardboard. A number of years ago it was ripped and kind of hanging so I just tore it off. Never had any problems without one, and the car is approaching 14 years/200k miles.

Its definitely the gravel shield/stone protector, though I Googled both of those and still can’t find a picture of one. Cover was a bad word for it, unless its covering the ground from my leaking fluids, but I couldn’t think of another word for it.

As far as the fasteners go, I’m assuming they are not reusable. One doesn’t even have access to the opposite end; its completely enclosed by metal parts. The other ones I can at least touch the opposite end. They look most like the last(fourth) one linked to by Joey P. They are threaded/serrated(word?), but they don’t have a hole in the flat end. I’ll buy some pliers and try to rip them out.

If it’s the ‘serrated’ kind, you can usually pry them out with a screwdriver and a pliers. It won’t look pretty, but if you don’t completely destroy it, it’ll go back in.

I may be incorrect, but they might be simple pop-rivets.

No, pop rivets are semi-permanent. They have to be drilled out. Gravel shields are designed to be taken off and put back on.

pop rivets might only be used where it is not intended to be dismantled. plastic rivets might be used where service access is needed.

plastic barbed rivets might be removed by prying up. you may also get to the backside and us pliers to squeeze the springy sides together or from the front side as it comes up squeeze from the side with a needle nosed pliers. make sure you are squeezing the springy sides together, which is not always easy to do in reduced light and vision angles. it isn’t always nondestructive of the fastener.

Chiming in with my own experience: Damn thing got ripped somehow and was dragging, so I tore off that part. Eventually took off the whole thing by just cutting it with some metal snips near the bolts. Easier than removing the bolts. Car is going on 200k+ miles and no problems related to this.

They pry out. Diagonal cutting pliers (commonly called dikes) can be used to get under the heads and lever them out of their holes. Don’t squeeze enough to cut them if you want to reuse them.

The fact that the cover is flimsy and soggy might be a clue as to its function. I tore a hanging shield off my old Mercury and forever had problems with water getting into the alternator.

I like this.

Best wishes,
hh

Never seen anything like that on any car I’ve ever owned, but damn that’s a good idea!

They sell a tool like a bent screw driver with a notch for pulling these things, very easy to use. A small prybar should be able to pull them also. They are almost always loose when I replace them, new ones are cheap at an auto parts store. I doubt the cover is very useful. I usually leave them off my vehicles, but replace on customer’s cars.

When this thread first started that was the first thing that came to mind and I tried (albeit, half assed) to find a picture of that tool (it’s what I use). I always called it a cat’s paw, but as it turns out, that’s something else.
Here’s one.