Sudden Engine Knock

**RoudyYates** · 07-25-2011

I have a 2000 Grand Prix gtp with 160,000 miles. This past weekend I suddenly noticed pretty loud engine knock. To me in sound like a lifter knock but I am not certain. I know the Dex-Coolant can eat away the gaskets and I needed an oil change anyway so I changed the oil thinking I would be able to tell if there was coolant in the oil. Long story short I couldn't tell but the coolant level is not noticaably dropping. With the new oil the knock got drastically quieter, after a few loud ones and, I presume thats because the oil haden't reached where ever the knock is. Anybody got any ideas on what can cause a valve knock to suppenly appear. Its barely audible under 1500 RPMs and really loud above 3000. No noticable power lost but It not like im going to push it with the engine knocking like that. I used the old screw driver method to see If I could hear where it was coming from with no luck.

**BillBoost37** · 07-25-2011

Very tough to say. how about getting us a vid so we can verify if it's valve etc to help you out.

**TLSheff** · 07-25-2011

Compare to videos on page one of this current thread. If it sounds like this, read on... if not a video of what your is doing would help greatly.

http://www.grandprixforums.net/engine-knock-49093.html

PS ^^^ Is NOT lifter noise, so hopefully yours isn't like this one

**RoudyYates** · 07-25-2011

I went to to auto parts store and one said it was a rod knock and one said it was a lifter knock but niether was sure. Im leaning toward the rod knock but really, really dont want it to be that. I dont really knowhow to upload videos so I just linked on to on youtube. Thanks for your help.

‪engine knock‬&rlm; - YouTube

**Fivefingerdeathpunch** · 07-25-2011

rod knock.

does the oil have sparkles in it???

**Hippo Machine** · 07-25-2011

Originally Posted by fivefingerdeathpunch

rod knock.

Does the oil have sparkles in it???

ooohhh pretty sparkles

**Scottydoggs** · 07-25-2011

Rapin Rodney ‪Rappin' Rodney‬&rlm; - YouTube

**RoudyYates** · 07-25-2011

Damn, well i thought it was a rod knock but I was praying it was not because that and my motorcycle are my only mode of transport. I didn't see any shavings in the oil. I believe the oil plug even has a magnet that didnt have any shavings in it. But who knows. Anybody got a LS37 engine fore sale or ideas on Engine swaps. Will a more powerful engine even fit in this car?

**Fivefingerdeathpunch** · 07-25-2011

find another L67 and just swap them.

**Devonth** · 09-04-2013

bearing flakes are not normally magnetic.

**tms8582** · 09-04-2013

Could be main bearing knock too. Happened to me before with a l67.... You won't always see metal in the oil because the drain hole is higher than the bottom of the oil pan. Main or rod knock doesn't matter the lower end is toast. I bought a junk yard motor for $750 with 110k and swapped the motor myself. If you can't do the wrenching a good shop can for around a grand.