Rattle in engine bay when cold starting

[turbodude]

Update: Video posted!!!!!

Hello, maybe someone can help before i start tearing things apart under the hood to try and figure this thing out blindly. Here is the situation:

Whenever i start my GS-t in the mornings or after it has been sitting for an extended period of time it makes a very audible vibrating, rattling almost a grinding type sound for about 1-2 seconds at the exact point where the engine actually turns over before going into normal idle. Again, the sound is not there when it's actually cranking or idling at normal RPM, but once the engine catches and officially turns over, for 1-2 seconds i get that hideous rattle/grind sound. It's not the starter or anything to do with that as i know what an un-engaged/stuck starter sounds like and it is a much different sound.

When i start my car after putting gas or making a pit stop at the store there is absolutely no sound or noise at all and sound completely normal. Just when the car is cold.

My best guess would be perhaps the tensioner pulley or something that is being ran off the belts? any help would be greatly appreciated. Thanks!

http://www.youtube.com/watch?v=T--pKLNBYFI

 

[crand]

Are you sure its not your belts? May just need to tighten your belts to the alternator,a/c etc...

 

[turbodude]

Hmmm... Could be just the belts i guess. I can double check the tension later this evening.

 

[turbodude]

Updated with video! Here is a video i put on youtube i made of the sound... Please help! I dont think its the belts as it sounds like its coming from the other side of the engine

97 Eclipse GSt wierd start-up noise from engine - YouTube

Was under the hood for about an hour and still could not pinpoint it.... Anyone???

 

[turbodude]

Any thoughts? anyone?

 

[ZeroRain]

It sounds like something is rattling around the bellhousing to me. Is it a 5spd? Maybe something with the clutch?

Zero

 

[g4ebguy90]

Uhh low pressure to the lifters.... About every car I have ever had, does that at cold start for 1 or 2 seconds.

I think it's internal.

 

[turbodude]

-ZeroRain, It is a 5 speed. thanks for your response... However i think it is coming more from under the valve cover area. I know it is hard to tell from the video.

-g4ebguy90, thanks for the input. I never knew that was a common thing. well, that probably is it then. I'm guessing there is no fix for it? If not i guess i'll just live with it as long as it's not going to cause any collateral damage to anything. Thanks

 

[Tribal_RS_96]

Thats a nice looking car, I dont know what that sound could be either, because after that 0.5-1 second you dont hear it again, so it cant be the lifters or anything stuck in the head area. Thats all i got

 

[WeaselHack]

Sounds to me like TOB rattle...Do you get the same result with the clutch pushed in on cold start?

 

[hollyskittles]

i used to have an old chevy pickup that did the same thing it ended up being a backfire through the carburetor i dont know if its possible in a fuel injected engine so feel free to correct me but it only did it on cold starts like after sitting for a night or on a cold day same peramiters as you if thats not possible then i would have to go with the throw out bearing theory only things i can come up with

 

[turbodude]

Thanks for all the feedback guys, yes it does still make the same noise even with the clutch pushed in fully. I'm just at a loss for ideas. Sound like something i really can't just fix anyway without tearing into the car. So, hopefully with time as my build progress continues with me upgrading the clutch and pressure plate, rebuilding the tranny, swapping the cams, etc, etc.... it will eventually work itself out, at least i hope.

 

[SeaveeDSM]

Could it be the starter motor's gear not disengageing cleanly or quickly enough from the flywheel when its cold at the initial startup ?

If the car is lifted - and propely supported with jack stands - can you hear it more clearly from underneath?

 

[forcefed4]

That's funny, my 97 GST made the same noise with the same conditions. I never figured it out. I changed the clutch, TOB, and the crank pulley. I think it still does it to this day, I sold it 3 years ago.

Maybe check out the starter as Rick suggested.

 

[turbodude]

Thanks for all the input, I'll get under the car first thing tomorrow morning to check it out and will report back afterwards. I'll do a couple consecutive starts to try and get the EXACT location area and not just the general area.

 

[turbodude]

Still could not pinpoint the sound.... Still sounds like its coming from the general area i showed in the video but not 100% sure. I'm going to be getting a new ACT clutch kit here soon installed, i'll make sure everything gets checked out good while everything is disconnected and hopefully with some luck it will then go away once everything is bolted back up. Thanks again everyone for your contributions.

 

[LiquidX]

Use a long screwdriver and use it as a stethoscope. I would start with the transmission by the clutch and then the starter area.

 

[blue6gen]

Wow! Mine does the EXACT same thing! I was thinking it was a starter/flywheel issue as well, but it is strange how it only does it upon initial start up after a good bit of down time.

 

[turbodude]

Wow! Mine does the EXACT same thing! I was thinking it was a starter/flywheel issue as well, but it is strange how it only does it upon initial start up after a good bit of down time.

Maybe this problem is just with us white cars, dang discriminating engine noises.

Also, thanks LiquidX for the screwdriver tip. I'll give it a shot.

 

[blue6gen]

Maybe this problem is just with us white cars, dang discriminating engine noises.

Also, thanks LiquidX for the screwdriver tip. I'll give it a shot.

!! I needed that!

Keep us posted on your findings,