Slight Shuddering Sound On Initial Startup

Hello all! This is my first post here.

I have a 2000 Mitsubishi Eclipse GT. I bought it used in Feb 2004 from a Mitsubishi dealer and it had 57000 miles on it. It now has close to 80000 miles on it and hasn't given me any trouble so far.

About 10 days ago, I had the fan belts in my car changed on the advice of the mechanic I usually take the car to for oil changes. He has always given me good advice and always discusses pros and cons of any change with me. He said that he was able to see cracks in the belts and that I should have them changed.

I took his advice and the belts indeed were in a bad shape. These were the original factory belts.

No other work was done that day except for his taking a look at one spark plug to see its condition. He didn't replace it with a new one, but merely put it back in place.

Anyway, the problem I come with started the following morning. When I started reversing out of my garage, I heard a kind of stuttering sound along with the smooth idling but at about half or a quarter of the frequency of the smooth sound.

This sound continued as I hit the brakes, put the car into drive and slowly pulled out of my apartment complex. About 30 seconds later it was gone.

I was intrigued by that and pulled into a parking lot, stopped the car and started it again. Nothing.

Later in the evening, when I was headed back from work, I heard the same sounds. 30 seconds later, gone again.

I have noticed this pattern since then:

When I start the car after long periods of rest (I guess the engine cools down completely), I hear this sound for about 30 seconds to a minute at the most.

If I were to then stop and start the car again, I don't hear it.

Could somebody tell me what the problem could be?

i assume your car is an auto/sporty correct? does it only happen on cold starts?? you may want to go about warming your car up before you use it, cold starts are hard on an engine and immediate use isn't normally recommended, if its cold outside def. let it warm up for a minute. cars w/ higher miles def. act differently based only on temperature

Thanks for your reply!

Yes this happens only on cold starts (the car has been idle for about 8 hours at least). Also my car has the Sportronic transmission which I operate in the Automatic mode for routine driving.

I live in Orange County, California and the weather is quite mild at the moment - in the 60s in the morning.

I always allow the car to warm up for about a minute or so in the morning and for about 30 seconds before I drive back home from work.

I did try to see if letting it warm up for longer resulted in the absence of the sound, but I don't believe it does.

can you give a better description of the sound? i know its probably hard to describe it.

I'll try :)

The sound:

- is repetitive
- is dull, i.e. has more bass than treble (sorry, I'm an audio engineer ;) )
- is NOT sharp and clicky.

I let the car warm up for 3 whole minutes this morning and I didn't hear the sound when I reversed out of the garage. When I changed to "Drive" to move forward, I did hear it for a few seconds, but for significantly shorter than on previous occasions.

boy this is a tough one, i would have your ATX fluid checked to make sure its still good, i imagine you have to change it every once in a while and it would warm up faster when your driving as opposed to idleing, that would explain why itdoesn't last long

and just to brag, we've had 80s in MISSOURI until today, its been soooooo nice

there are some good aftermarket choices for ATX fluid that you should look into getting, i think BG makes some trans fluid for ur car but i'm not sure, so look around if you need some

i would get the tranny flushed at the dealership. i would only recommend the OEM fluid for the sportstronic transmission

Thank you for the advice! My mechanic asked me to leave the car with him on Friday evening so he could hear this sound for himself on Saturday morning. Even though his garage is just about half a mile from my place, I've been unable to get him to hear it because it stops by the time I get there, and I don't hear it again until the engine has cooled down sufficiently.

It does logically seem to have to do with the transmission in some way. Unfortunately, I'm not very knowledgable about cars and that's something I plan on remedying to some extent at least.

Where would I get the right transmission fluid for the car? The last time I got it changed, I remember that he looked up a table that detailed make/model and decided on a particular fluid on that basis. Should I buy a particular TX fluid elsewhere and have him change it?

Thank you for the advice! My mechanic asked me to leave the car with him on Friday evening so he could hear this sound for himself on Saturday morning. Even though his garage is just about half a mile from my place, I've been unable to get him to hear it because it stops by the time I get there, and I don't hear it again until the engine has cooled down sufficiently.

It does logically seem to have to do with the transmission in some way. Unfortunately, I'm not very knowledgable about cars and that's something I plan on remedying to some extent at least.

Where would I get the right transmission fluid for the car? The last time I got it changed, I remember that he looked up a table that detailed make/model and decided on a particular fluid on that basis. Should I buy a particular TX fluid elsewhere and have him change it?

get the fluid from a dealership.

^^ whut he said

dealership isn't always the worst choice and they'll help you more if u use their stuff

Hello again! I'm back with an update.

I left the car with the mechanic overnight and he heard the sound when he started the car in the morning.

He feels that it could be an issue with the timing belt. He says that the sound is coming from the timing belt housing and that without opening it up (which he estimates will take about 4-5 hours) he can't be sure if it's something loose in there or if the belt needs to be replaced. According to him, that would be at $400-450.

Another mechanic that my neighbor trusts wants me to leave the car with him so he can be sure, but he doesn't think it's a timing belt issue but that it's a problem with some part not getting the right amount of fluid at startup. Once it does, the sound disappears.

Your advice is much appreciated!

i think ur engine mounts are going
kinda like my car

i think ur engine mounts are going
kinda like my car

if the engine mounts were bad, then the sound would be there all the time.

It turns out that it WAS the timing belt. I took the car to the second mechanic's garage as they were highly recommended to me by two of my neighbors and left it with them overnight so they could hear the sound the next morning.

They isolated the sound as coming from the timing belt housing and on removing the cover, found that there was about 3/8" - 1/2" of slack! They were quite amazed that the belt was still in place.

They replaced the timing belt, tensioner and water pump (and a few other parts). The timing belt replacement was way overdue anyway since the car now has 8000+ miles on it.

I bought the car from a Mitsubishi dealership when it had 57K miles on it. They told me then that they had performed major services on it and that all belts had been replaced. In my inexperience and stupidity I took their word for it.

In the past month I've had the fan belts and the timing belt changed. I plan on getting a "major service" (spark plugs, transmission flush) done within the next two months. What other service would you recommend?

Just thought I should let you guys know! Thanks a lot for all your help!

In the past month I've had the fan belts and the timing belt changed. I plan on getting a "major service" (spark plugs, transmission flush) done within the next two months. What other service would you recommend?

Just thought I should let you guys know! Thanks a lot for all your help!

looks like you will have all the bases covered once you get those other maintenance items done.

the sound can also be called a bit grindy
violent shakes and extreme low revs fluxs
and usual happens on startup for 10secs
and yes on cold starts

i think some how this would relate to this problem

the sound can also be called a bit grindy
violent shakes and extreme low revs fluxs
and usual happens on startup for 10secs
and yes on cold starts

i think some how this would relate to this problem

i think he figured it out dude...:uhoh: