: 2001 STS engine knock

02-27-08, 10:07 AM
I have a 2001 STS with 66000 miles on it when I start car when cold it sounds like i have a rod knock on motor it starts to go away after running for a while ,it seems now it is is more noticible but like i said it quits down after a while any ideas were there any problems with the 01 STS engines

02-27-08, 11:02 AM
Warm the car up thoroughly, check the oil and go for a 10 mile drive. Get into the countryside or near a long OnRamp to a freeway. Slow down to <10 mph, put the gear selector in 2 and PUNCH IT ! Leave your foot in the firewall until you hit 70+ just after the 1-2 shift, then flip your foot off the accelerator and let the gearbox pull the car down to around 20 mph. Road clear ?? Do it again.

This is the talked-about "WOT" (wide open throttle), written up in here for years. It clears out the carbon in the combustion chamber quench area, which is very thin on a N* (and is the source of your cold knock), and it also heavily loads then unloads the piston rings, allowing them to rotate in their grooves, shedding carbon buildup.

If you've never done this, it's sort of unnerving the first time, and you'll get a real mess of smoke and garbage out the tailpipe. Maybe the second time, too. A N* is designed and built to RUN, and they're very happy that way.

A happy side effect is probably going to be better oil and gas mileage.

If you're antsy about running the car that hard the first time, work up to it. Search these performance threads and find WOT, carbon rap, piston rap, stuff like that. I didn't believe it 3 years ago, either. Now I do 2 a week just for grins and kicks.

02-28-08, 10:19 PM
Read the Technical Archives at the top left of this page.