: Northstar Making a Loud Noise - Need Help!



devistat00r
01-18-11, 01:49 PM
2001 Deville DTS with 93,000 miles. Drove the car to work with no problem. Went to leave for lunch and when the car started it made a loud clunking noise. Put it in drive and it continued to make the clunking noise.

The car drove but it seemed to lack power. Stopped the car and started it again, same clunking noise. While idling the car sounds fine. When in park under light acceleration it does not make the noise, when giving it a good rev it makes the noise (same as when driving it). It's not a constant noise. I checked the belts, they seem ok.

No codes, and no other issues with the car to speak of. It has oil, etc.

I have owned the car for the past 6 years and 60,000 miles.

Ranger
01-18-11, 03:35 PM
when giving it a good rev it makes the noise (same as when driving it).
Might have a good look and listen under the hood while doing that.

Submariner409
01-18-11, 05:33 PM
Yep ^^^^ Something's coming apart - accessory or water pump belt drives ??

devistat00r
01-19-11, 12:41 PM
Just heard back from the mechanic. I blew out a sparkplug (literally out of the engine). They are going to use a heli-coil, replace the coil, and new plugs for $850. Luckily I don’t need a new head.

Ranger
01-19-11, 02:03 PM
Well that would explain all your symptoms. Not sure how that happened. Someone must have over torqued the plug and stripped the threads. Who pulled the plugs last and when?

devistat00r
01-19-11, 05:02 PM
That's what's scary, I have owned the car since it had about 30,000 miles on it. The plugs have never been changed since I have owned it.

foxjohnc
01-19-11, 08:30 PM
Well that would explain all your symptoms. Not sure how that happened. Someone must have over torqued the plug and stripped the threads. Who pulled the plugs last and when?

Usually it is under tightening that causes the plug to blow out. When the plug is not properly torqued, it will not seal correctly. This causes the hot gasses made during combustion to seep out around the threads and will literally melt the threads. I have seen it many times on smaller gm engines but never a northstar. Ask the shop to give you the plug and post a picture on here if you dont mind.