clatter/rattle sound?

[irish44j]

First, engine fires up great and pulls well through the powerband (well, as well as an M10 can pull, that is).

So when I first turn on the car, I get a clatter/rattle sound that from inside the car sounds like it's coming from the middle of the dash. It usually goes away as soon as the idle comes down a few seconds after startup.

When driving, the only time I hear the rattle is when I am:
1. lugging because I'm too lazy to downshift or
2. accelerating hard in any gear.

again, the sound seems to come from the middle of the car below the dash. Haven't invesitgated yet much, but doesn't seem to be a heatshield issue or anything (which is what is sounds like), but figured I'd check in for anything to check.

otherwise, engine sounds smooth and good, other than usual valve tapping.

[Hey_You]

Possible clutch related item?

[Jaxx_]

does it sound like marbles in a glass jar?

[irish44j]

ok, so with the hood open I ran the car and revved it from the throttle body. I'll revise my location and sound now that I hear it from outside the car.

Sound: more like a squeaky chirp - like a cricket chirping really fast

Location: at the front of the engine. COuldn't run the car much because it's stuck in the garage on stands at the moment and don't feel like dying of C02 poisoning, but it sounds like it's coming from the alternator or fan clutch or something around that area. Pretty sure it's not a belt squeal since all the belt tensions seem right and the belts are pretty new. Tomorrow I'll get it ouside and use a hose to try to locate it specifically. If anything, it doesn't seem to be coming from the engine itself, so that's a good thing. The alternator on this car appears to be brand new, so hopefully that isn't it, and it's just a squeaky pulley or something. AC is deleted, so that's not it either.

[irish44j]

does it sound like marbles in a glass jar?

lol, no idea what that would sound like...I haven't had marbles in 30 years. Out of curiosity, what would such a sound indicate?

[thebutterson]

My guess would be the alternator or the belt driving it.

[EyExR]

2nd the belt.

Strange how it turns into a rattle inside the cabin though....

[Jaxx_]

lol, no idea what that would sound like...I haven't had marbles in 30 years. Out of curiosity, what would such a sound indicate?

okay, pebbles in a glass jar. Haha. That sound is chain tension and the chain rattling around.

[irish44j]

2nd the belt.

Strange how it turns into a rattle inside the cabin though....

keep in mind that this is a rallycross car with no interior carpeting, no back seats, etc. so I hear sounds from all parts of the car, lol.

I also noticed the sound after I put the skidplate on, which makes sense that the noise would be basically bouncing up off the skidplate back towards the car....probably it was always there but I never noticed it before.

okay, pebbles in a glass jar. Haha. That sound is chain tension and the chain rattling around.

ah.....yeah, I know what a loose/worn/untensioned timing chain sounds like and I'm pretty certain this isn't that sound.

In any case, hopefully I can definitively locate it tomorrow.

[Hey_You]

Like...timing chain? I suggest checking your tensioner spring if that's what Jaxx is saying.

[irish44j]

I know what a loose/worn/untensioned timing chain sounds like and I'm pretty certain this isn't that sound.

Like...timing chain? I suggest checking your tensioner spring if that's what Jaxx is saying.

:)

[Smelser]

If its a cricket chirp, sounds like the drive belts, if you have any sort of wax, or TIRE CHALK is the best, use that to CAREFULLY aply to the drive side of the belt while it is running, and see if it goes away.

[irish44j]

took some stuff apart tonight and (after removing the clutch fan, which will be replaced with an electric) found that the water pump pulley only had 2 of the 4 bolts holding it in present, and they were 2 next to each other. So my guess is that the pulley wasn't sitting flush and perhaps that was causing the squeak.

Also, the teeth on the upper end of the alternator adjuster were sheared off. Luckily the p/o had a spare adjuster rail in the box 'o parts, brand new. With that in place the belt deflection is less, and its tighter.

Also pulled the alternator and checked and it feels new...no play, no noise, super-smooth.

Guess we'll find out tomorrow.

[irish44j]

well, the sound is gone. Not sure what it was, but it's gone so who cares :) Was either a pulley, belt, or cooling fan issue I guess...

[devon.818]

squeaky belts are a MUST to replace. i called it after reading your second post, read on and gave myself a pat on the back lol


driving to work thinking, "hey, the belts stop squeeking, guess they warmed up or something", when you are tired and not thinking, well that sucks when you realize OH SHIT! i just lost my access. belts!

lucky for me i was at the top of a hill and 4 blocks from work, coasted 2 more blocks to a parking space and RAN.



tldr, noisey belts, replace, dont get stranded.