underbody splash shield/diffuser?
 

hi, i'm new here. i just got a 2005 mazda3 hatchback last saturday with 52,000 miles. it's exactly the car i wanted and i'm thrilled that i got it, but there are a few glitches with it:

1) the plastic shield under the engine is pretty messed up. when i took the car to the mechanic to check out the car and see if it had any problems (just to be safe) he said it had been in a front-end accident at some point but only suffered cosmetic damage, with the front clip and hood having been replaced. apparently the underbody splash shield wasn't repaired, so when i got the car it was hanging down on one side. i've done a makeshift repair so that the shield isn't hanging anymore, but it's cracked in a couple places, still sags in the middle, and needs to be replaced, especially because it makes a flapping/clicking noise on the highway above 60/65mph (or at least, i assume it's the shield doing that).

ANYWAY, i managed to find out the part number (BP4K-56-111L) but after that i hit a dead end. the point i'm getting to is that, has anyone had any experience replacing this part and if so, where/who can i order it from?

2) the steering sporadically shimmies around 60mph as well. i've done a bit of research and it sounds like the wheels just need to be balanced, but if there's any other possible reason for the shimmying/vibrating, i'd like to know.

3) the rear wheels have a noticeable negative camber; i'm not sure if that's normal or not. (don't think the car was lowered by the previous owner)

4) a TON of road noise. i know this is normal for the 3, but even so the amount of noise seems excessive. i think it may be partly due to the tires, which are yokohama low profiles that make a sort of rythmic sound at speed, but again i'm just not sure if the car is supposed to be as loud as it is.

sorry for the long post, i can be a bit long-winded but i just want to make sure my new dream car is in good shape!

All of the Above
 

Good Day.

Coincedently, I am in the process of replacing the splash gaurd on my M3. Originally damaged on a parking curb. The M3 is too low to the ground for my liking. I may have bought a Dodge Calibre in retrospect. I am ordering the part through my Mazda dealer for $135 Canadian ( $120 US ?)

I was also unpleasantly surprised with the road noise which I never noticed on test drive. The slightest bit of road grit or gravel is extremely loud.

Highway vibrations I suspect are possibly high performance tires not perfectly balanced or inflated. Maybe simply an alignment. I absolutely hate the Goodyear Eagles supplied with my 2007 M3. Overpriced, poor traction, poor treadwear. Replacing at only 35000Kilometrs soon with the General UHP for about $140 - way less than the lousy Goodyears.

As you can tell, I am not super happy with my M3 but it has a lot of pros also. The main reason I am keepig it is simply because of decent gas mileage. Also, very good handling. :tightass:

the road noise doesn't bug me if it's normal, it's just that the amount my car has seems excessive even going by what i've read. i think part of it is down to the wheel balance (you can hear the wheels rotating, if that makes sense, at lower speeds, and when you get up to highway speeds the sound fades away as the steering starts shimmying) and partly due to the tires. can't afford new tires at the moment, but i think when i get the wheels balanced it'll be alot better. (and of course when the shield is replaced there won't be the clicking on the highway)

i agree about the ground clearance though. especially because my car came with small bumper extensions front and back, which were a factory option, and while they look good i've already scraped them 3 times...i'm being more careful now =/

PS i think you made the right decision with the 3, at least compared to the caliber, which i hear is a crapbox ;)

On my 2006 Mazda 3, I had the dealer replace the engine oil and filter in the beginning. I decided to do it myself afterwards and found out that the dealer had cut a hole in the splash shield below the oil filter so that they didn't have to remove the shield. The hole looks ugly but I will live with it for now. I remove the shield completely when I do the oil change. It gives me a chance to look around with the shield removed.

I've got a 2007 mazda3 and I unfortunately had the same thing occur as you, Fud. Bashed a parking curb that was hiddin in the snow, at speed. Splash shield obliterated... the majority of it falling out on the road a couple days later - pretty much ruined my Christmas.

I'm getting mine in ASAP for it to be fixed. Does anyone know how many pieces there are to it??? From my observations (albeit without jacking the car up) there is the shield itself, and then two pieces that bolt into the front wheelwells somewhere. I'm going to need all three by the looks of it.

What's worse, is that now that the splash shield has fallen off, there is a strange rubbing/grinding noise that occasionally emanates from the front right corner of the car (the opposite corner that took the hit) - it doesn't seem to discriminate... it happens when the car's rolling, and when it's stopped. Felt a little feedback in the brake pedal too. :-( I'm hoping it's nothing TOO TOO major... perhaps just a piece of the splash shield that's left that's rubbing the front right wheel for some reason.

Just the kinda crap you don't need, hey?

The shield should be one piece - it is on mine (2006). You need to look under the car asap to see what is going on. There is likely pieces of the under shield still hanging on and it is good to look around anyway to see if there is any damage. Regular steel car ramps will not work as the spoiler will hit the ramp before the wheels get a chance to climb up the ramp. I made mine with pieces of 2 x 10 lumber and it works fine. My daughter's 2003 Protege will not go up the steel ramp either.

thanks marty.

yeah, the splash shield in fact IS one piece. there are two other parts however that attach it to the wheelwells that are cracked as well. I took a good look under the car and one of the wheelwell pieces was occasionally rubbing on the serpentine belt. I cracked out the tools and took OFF the piece that was touching the belt (as it's not doing anything anymore anyways, except for just hanging there) until I can get the car in for repairs on the 6th Jan.

Consequently, the evil noises have stopped. Priced out the parts - splash shield is $115 and the two wheel well pieces are $15 each.

Suppose it could be worse.

REPLACE YOUR SPLASH SHIELDS! See below for why.
I was just talking to a buddy. He has a 2007 and I have a 2008. My oil change place left out all but 3 screws from my splash shield, and of course, one fell out. So I was dragging it around for a while. I took it off until i could find replacement screws. i wasn't happy with what Autozone had for that, so I got some from the hardware store that should work.
Anyway, it's been off for a few weeks, and thankfully, it hasn't rained here in Florida for the whole month of October (highly unusual and a record).
Anyway, my buddy tells me he took his off years ago because it was easier to change the oil and such and didn't see the need.
His A/C just quit working and when he took it in, they told him the compressor was rusty and seized.
WHY YOU SHOULD PRESERVE AND MAINTAIN YOUR SPLASH GUARD!
The compressor hangs low under the passenger side, near the right tire. When you turn right when driving over wet roads, the water splashes right on the compressor! Not to mention just the potential road hazard hitting it. That squealing/squeaking etc. noise you are hearing may be your a/c compressor, belt slipping, pully tensioner, etc. EVERYTHING is on that side and exposed to the undercarriage!
His quote from the dealer: $700 just for the compressor (not including labor), no they won't use rebuilt. To preserve the warranty, they want to do the drier and condenser too. Total bill $1700!
So make sure you put it on and seal it up nice on that side!

FWIW, my compressor had problems long before I lost my shield. Expensive. I'm not paying the $175 they wanted for a new shield either, so off it remains. The excessive road noise is often bad front wheel bearings. It sounds just like road noise and gets progressively worse until you finally figure out that no car has road noise that bad. The process can take a couple years! I know bearings and noises and never would have thought "bad bearings" but that's what it was.

The Goodyears are so bad they should be illegal. The shimmy is probably bad tires and just balancing won't help. The rear camber is normal if it looks the same on both sides.