Clicking/tapping engine noise: Flywheel?

[Brian]

A few days ago my SVX started making this rythmic noise, like a tapping, clicking or knocking. It does so from the time the engine starts, but it lessens somewhat when I shift it out of park and while driving. I had it at a mechanics' that specializes in exhausts, and he listened to the engine through a scredriver from underneath while he had it on the lift. He said that it wasn't coming from the engine, but from the flywheel, that it might be cracked or have a loose bolt. He suggested I take it back to the place that rebuilt my transmission the other month. (They had replaced the old flywheel back in June when they did the transmission, because it had been badly cracked.) The transmission shop confirmed that all the bolts were in place, but they won't be able to get it up on a rack and take a good look at it until next week. So, in the interim, I decided to take it to my regular mechanic. He listened to the engine block through a screw driver from above. (no lift there.), but couldn't determine its origin. He agreed that the flywheel could be one possibility, but said it could be coming from somewhere else in the lower part of the engine. It seemed to be more towards the passenger side than the driver side, I think.

Has anyone else had a noise like this? Is there some other culprit besides the flywheel that I should be focussing on? If it is the flywheel, then I really want to know what the underlying cause is: Why did a second flywheel fail? And why so soon after the first?

I'm planning to drive it as little as possible, if at all, until I take it back to the transmission shop.

[Earthworm]

A cracked flywheel will do this. I believe that someone was going through flywheels (flexplates) until he realised he was missing at least one of the dowel pins that go between the engine and transmission.

[Amazonparrot]

Mark my words...def. a broken flexplate...luckily its only a $23 part...the labor however....


-Good Luck!

[SVXRide]

cracked flexplate make sure to check if the engine is missing either (or both! ) of the alignment dowell pins that come out of the back of the engine block and line up the trans case.
-Bill

[SVX-FF]

Will a cracked flywheel make a tapping noise, like a valve tap, but only after 3000 rpms? Mine does this. It sounds like it is coming from the exhaust.

I am still stying to get my garage back together so I can work on her. It is hell when you move.

Steve

[SVXelerator]

Originally Posted by SVX-FF

Will a cracked flywheel make a tapping noise, like a valve tap, but only after 3000 rpms? Mine does this. It sounds like it is coming from the exhaust.

I am still stying to get my garage back together so I can work on her. It is hell when you move.

Steve

no. does it make the noise after 3000 rpms in gear or while in Park?

[Brian]

Thanks for the info about the dowel pins! I hope you're right. My regular mechanic thought it sounded more like the noise was coming from somewhere in the lower engine, but he didn't listen to it from underneath the car.

[svx_commuter]

Easy to tell if it's the flex plate. Get DOWN on the ground behind the front wheel and listen. If the tap tap tap is LOUDER then it is the flexplate. There is no metal transmission housing covering the flexplate at the bottom so the sound travels out pretty easy.

Anyway you should not be paying for it. It is my opinon that the AT rebuilder/fixer broke it. THey could have forgot to loosen all the bolts or maybe one before taking out the AT or forgot to put in a dowel pin or both or pulled the AT and engine TOGEATHER with the bolts instead of getting them close before putting in the bolts. It wasn't broken before the job. Was it?

Flexplate abuse $uck$

Well then again it might just have been cracked to start with and just went the rest of the way thru.

[Trevor]

Originally Posted by svx_commuter

Easy to tell if it's the flex plate. Get DOWN on the ground behind the front wheel and listen. If the tap tap tap is LOUDER then it is the flexplate. There is no metal transmission housing covering the flexplate at the bottom so the sound travels out pretty easy.

Anyway you should not be paying for it. It is my opinon that the AT rebuilder/fixer broke it. THey could have forgot to loosen all the bolts or maybe one before taking out the AT or forgot to put in a dowel pin or both or pulled the AT and engine TOGEATHER with the bolts instead of getting them close before putting in the bolts. It wasn't broken before the job. Was it?

Flexplate abuse $uck$

Well then again it might just have been cracked to start with and just went the rest of the way thru.

Good one and THE POST needed in this thread

What is more if it WAS cracked they should have discovered this fault.

Swat up on all this and go to them, with your gun loaded.

[Brian]

No, THIS flexplate wasn't broken when they did the job. When they pulled the tansmission for the rebuild, they found that the old flexplate was badly cracked. Cracks connected most of the bolt holes. They replaced it with a used but uncracked flexplate. That is the one that I suspect is the problem now.

The flexplate makes even more sense to me as the culprit because of this: My car had been intermitently making a similar sound before I had the tranny work done and an exhaust leak fixed 2 days before the tranny went. Back at that time my regular (third party) mechanic had listened to the engine through a screwdriver, again from above only. He said it wasn't coming from the engine, and surprisingly (to me) attributed it to an exhaust noise. I drove it for months with that noise coming and going, since an exhaust leak has no mechanical danger of causing further problems. It went away after the work, so I assumed he was right, and that it was getting the exhaust leak fixed that cured it. But since the old flywheel had been cracked, I now suspect that he was wrong, and the flexplate was making the noise that other time, and having the trans. shop replace the flywheel is what really stopped that noise.

Then again maybe they were two completely different noises, from 2 different sources. It just makes more sense that way. But it still leaves me with the mystery of how the previous flexplate got cracked. It was more than a year between the time I had my engine rebuilt and the time the old noise started. Neither the engine or the transmission had been messed with during that period.

[Brian]

As far as me not having to pay for it, I agree. The transmission work was guaranteed for 1 year. The transmission shop replaced the flywheel, so I certainly hope the guarantee covers that as well.

[SVX-FF]

Originally Posted by SVXelerator

no. does it make the noise after 3000 rpms in gear or while in Park?

Sorry for the long awaited response but yes it does.

[SVXRide]

Originally Posted by SVX-FF

Sorry for the long awaited response but yes it does.

yes in gear or yes in park or yes, both?
-Bill

[SVX-FF]

Originally Posted by SVXRide

yes in gear or yes in park or yes, both?
-Bill

Sorry about that Bill I have been sniffing paint fumes all last night. Yes the noise is there in both gear and park. I is louder when the cars is warmed up.

If I am over 3k rpm and let off the gas to coast then the noise goes away.

Steve

[SVXRide]

Originally Posted by SVX-FF

Sorry about that Bill I have been sniffing paint fumes all last night. Yes the noise is there in both gear and park. I is louder when the cars is warmed up.

If I am over 3k rpm and let off the gas to coast then the noise goes away.

Steve

Steve,
You know, opening a bag of charcoal (the kind without the lighter fluid in it) does wonders to absorb paint fumes

Doesn't sound like you've got a flexplate problem. The typical flexplate "hammering" actually goes away with higher rpms (i.e., it's worse at idle). The fact that the noise is louder when the engine is warmed up points toward something expanding due to the heat...can you provide any more details?
-Bill