Subtopic	Posts		Updated
	Tapping noise after start-up...?	1		04/15 04:51am

By SteveH on Tuesday, April 10, 2001 - 09:31 am: Edit

OK guys, I have a persistant (spelling??) tapping noise coming from the lower rear engine/torque converter area. Fairly light tapping and related to engine RPM (also taps faster than once per revolution it seems). It either goes away or is drowned out by engine noise at about 3000 RPM. This has been going on for about 2 weeks. I have checked the oil and it is full with no metallic floaties. Any ideas?

By Joshua Bova (Jbova) on Tuesday, April 10, 2001 - 11:20 am: Edit

Do you notice the tapping when the engine is under load or only at idle? i.e. If you put the truck in gear and give a little gas does the noise get worse or dissapear.

-josh

By nadim on Tuesday, April 10, 2001 - 11:46 am: Edit

valve clearence/timing?...that is my guess...but better take it to a mechanic...it is an old '57 buick anyhow...

By SteveH on Tuesday, April 10, 2001 - 02:29 pm: Edit

Joshua,
After a little testing, the tapping goes away under load.

By JC on Tuesday, April 10, 2001 - 03:42 pm: Edit

check the converter/flywheel bolts. when they come loose people seem to think it is engine when it is the converter bolts. you will need a tool to hold the flywheel though.

Joe casey

By Joshua Bova (Jbova) on Wednesday, April 11, 2001 - 04:36 am: Edit

I am not familiar enough with the problem suggested by JC to dismiss it, however, with the symptoms and location of the noise that you describe I would be surprised if it were timing. I don't know what year your truck is, but a problem that is common in the 3.9 engine of the 94-95 NAS Discos is cam walk. This may be something to look at.

-josh

By SteveH on Wednesday, April 11, 2001 - 04:59 am: Edit

Josh, Mine is a '98 S1. I am just hoping that it's not a rod bearing or something like that. After two weeks, I think if it was a rod bearing it would be gone by now. Also like I said earlier, I have no mettalic floaties in my oil. I should be getting off work a little early today (for a change) and plan to do some more looking. Praying that it is something easy to fix. Thanks for the input

By SteveH on Wednesday, April 11, 2001 - 02:20 pm: Edit

OK guys after a more through look, it seems to be coming from the torque converter. I pulled the small round inspection plate off the bottom of the bellhousing and didn't see anything obvious, however there are small nicks and scratched around the circumference of the converter. Anyone have any ideas? Thanks

By Dave Thomas on Wednesday, April 11, 2001 - 03:25 pm: Edit

A while back I had a 'tapping' sound that seemed to be coming from the torque converter. It turned out to be broken cat converters. With the car running and snooping for the sound with a tube it sounded very much like something in the torque converter.

I cut open both of my cats and sure enough.....they were pulverized. Removing the catalyst and welding them back up solved the problem. Nice power gain as well ;-)

You could pull your Y pipe off and shake it. That's how I could tell. Well, that, and I could
pour broken catalyst out of the manifold side of the Y pipe!

By Nathan Crabtree (Nathan) on Wednesday, April 11, 2001 - 03:52 pm: Edit

Steven
Sounds like you have a flywheel problem. If the converter has nicks around it, then there is something loose. Check the bolts where the converter is bolted to the flywheel and also check the flywheel bolts. If you see that there is a bolt loose or missing (DON'T DRIVE IT) get it fixed. If you are driving it and all the bolts break, you might have it in the seat with you.
Nathan