Rattling noise in the engine compartment

E

enterflux

:
2002 Mazda Protege5
Hey guys! I've been having a problem with my P5 for about half a year now and my mechanic hasn't been able to figure it out, so I figured I'd give you guys a chance at it. I *might* be able to get an audio clip sometime of then noise it makes, but I can describe it (from what I think) pretty accurately.

When I'm driving, usually at 30+ mph, and I go over any rough point in the road, like a slight bump or a rough patch where it shakes the whole car, I get a strange noise from the front of my car that sounds like the compressor of a mini-fridge rattling when you shake it. When it makes this rattling noise, I can also feel the vibrations from it in my pedals. It doesn't matter whether I'm accelerating or coasting, so I don't think that it's got anything to do with the engine mounts or probably the transmission or drive train. I've been wondering if it may be something to do with the suspension. Also, it doesn't do this (or at least I can't hear it) when I go over something serious like a speedbump in the road.

Hope you guys can make some sense of this, and thanks in advance for any help you can offer!
 
Last edited:
If it happens when you hit a bump or accelerate It might be your mounts, Have you checked them? It also might be a uniquely blown strut. Mine used to vibrate and make a sucking noise when it was coming back up. You should open your hood and push down as hard as you can on the frame right behind the grill, and listen carefully for any weird noises as it goes back up.
 
Thanks for the quick reply, but like I said, it doesn't happen when I accelerate or hit large bumps. Also, I have tested my struts and they don't make any sort of sucking noise when it comes back up.
 
Id be checking bushings, it sounds like something is hitting a certain harmonic and vibrating in a bracket. Only prob is there are a bunch of bushings it could be and they are tough to check . . .
 
It's not really a vibration though. It only lasts a second or two and it's more of a clunking rattle. Like something heavy and solid knocking against the frame of the car.
 
i would check strut tops control arm bushings or the sway bar. sounds like sway bar end links or bushings to me. you can check the sway bar bushings and links with the suspension loaded and just grab the bar and forcefully try to move the bar and see if there is any play in the end links and the same for the bushings. as for the control arms look for cracks or separated bushings
 
Now that you mention it, sway bar sounds like it would very much make sense. I'll make sure to check that out today and get back to you guys!
 
i have this same noise for a few years now. it happens on say a pothole or going over joints on a bridge. as far as i can tell it is not directly suspension related (as in not a direct failure of a suspension component).

one possibility is the cowl shake or shimmy as miata owners have similar issues with theirs. their solution is usually chassis stiffening like a tower brace or other form of bracing. i installed a used protege5 strut tower brace and it has not gone away :/
 
Hi, I didn't feel like starting a new thread, so here it is: my car also seems to have sort of this high pitched rattling sound, but it only happens around 3K to 4K RPM, its like this fast rattling? and its there if the car or moving or not.

What could it be? I've been trying to figure it out but gotton no where. I've had it ever since I bought the car.
 
I found the sway bar today and gave it a few hard tugs on both sides of my car and it seemed to be plenty tight.... I'll see about checking the heat shield and catalytic converter tomorrow.
 
Hey there, Hopefully i can help...
I bought a SP20 (Pro 5) about 6 months ago.. Had the exact problem.. done the exact same things as you have done,
Had brand new engine mounts and gbox mounts put in a week before i bought the car so they were okay. Checked all bushes, shocks control arms, sway bars.... Everything was ok.

Anyway, just this weekend i had my head under the car poking around again,,, took a look at the cross member, seemed perfect (no scrapes, dets etc.)
But for some reason i decided to give it a bit of a hit with my fist.... and there it was!!! that damn rattle!
It seems that over the years of people jacking the car up from the cross member it had ever so slightly bent it so that it was 2mm or so from the gearbox...
once i had investigated further, there was a slight wear mark from it touching...

Easiest way to check is to put two long (and strong) screwdrivers in between the cross member and the gearbox, then pry the cross member far enough away from the gearbox so that you can shove a decent sized piece of Exhaust rubber (heat resistant) in between.
then take the screwdrivers out so that the rubber is wedged in there.
Now go for a 5minute spin and see if that fixes the problem...

NOTE: the above is a temporary 'diagnostic fix' ... not the solution as the rubber will fall back out withing 10mins or so :)

If that is the problem, then you have to drop the cross member and bend it back to how it should be.. maybe a washer or two on the rear cross member mounting point to give a few mm more clearance..


Hope this can help you
P.S. this is my first Post :)

Cheers,
AzzA
 
Holy cow. Thanks for the response! I'll be sure to check that as soon as possible. I'm out on Thanksgiving break right now, so my car is about 300 miles away. :p

_________

12/10/11

So close! In a week and a half or so, I'll be home for Christmas break and my plan is for a couple days, jack my P5 up a few feet so I have some clear room to work and I'm going to give her suspension and chassis a thorough look-over to see if I can't figure out what the problem is. I'll get back to you guys with results/aftermath. :p
 
Last edited:
Hai again!

So, I *think* it's my radiator (that sucker is LOOSE,) but I didn't think that it could be making that much of a noise. My plan tomorrow is to jack up the front end while I'm home, take the radiator off its mounts, and bend the mounts back into place. I think the problem has been probably that somewhere along the line, the two mounts below it have been bent lower, leaving that half inch gap of wobble room in the top mounts. I'll let you guys know what happens!
 
So, I think it actually is my radiator. I had to restort to bending the upper brackets down closer, and I think that is quieted the noise. My next step is going to be trying to find some way to make that radiator solid so it won't shake anymore.
 
Please log in or register to reply here.

Similar threads

jawn
Protege5 running rough, smoking from intake, high idle then dying…Help
Replies
1
Views
743
jawn
jawn
jawn
    • Like
Buying a Protege5, possible VTCS issue?
Replies
7
Views
2K
njaremka
N
BenjiHoggi
    • Like
Troubling Engine Noise
2 3
Replies
47
Views
9K
BenjiHoggi
BenjiHoggi

Latest posts

Back