GM Top Engine Cleaner....solve knocking?

**cascade** · 05-07-2006, 06:07 PM

I just changed my plugs at 50,000 miles after hours of labor (I hate you plug 8).

Anyways, I'm trying to just do basic maintainance on the car, and all has gone well so far, but I'm still unable to ditch the knocking I get sometimes.

When I go WOT, I get a rapid clicking noise which I believe to be knocking, around 4,500 to 5,500 rpm range. I run 93 octane gas. When I slowly accelerate, but don't shift and just let the car run up to 5,000 rpm or whatnot, it doesn't knock. It only seems to do this when I floor it.

I've heard of the whole oil getting into the intake and such problem, and heard that it has been known to cause knocking. I need to solve this crap asap and get my engine running nicely again. I bought some liquid "GM Top Engine Cleaner" from the local Chevy dealership. I'm about to run it through, but I've heard that doing this can cause crap to go all over, and will cause me to need to change my spark plugs and oil once more. I'm hesitating, as within the past few weeks both of these have been changed, and I'd be pretty pissed to have to change both the plugs and the oil again in order to eliminate this knocking noise.

Any suggestions on how to troubleshoot this knock, and opinions of the whole Top Engine Cleaner would be appreciated.

Thanks,
Rich

**SeVeReDiStOrTiOn** · 05-08-2006, 09:02 AM

About that GM top cleaner...make sure it's the right stuff. The stuff you want is in a metal can...about the size of a bottle of water. The other GM cleaner is in a really small plastic bottle(size of a medicine bottle) and is a liquid like you said....it's a lightish brown color...DO NOT USE THIS ONE. It's a concentrate that GM uses in some machine that cleans the top end, and must be used in small amounts in that cleaning machine.

About the knocking....i'd put it on a dyno and have them monitor the a/f ratio. Do a few pulls and see if you're running lean....hopefully you can find a place that'll do a few runs for cheap.

**cascade** · 05-08-2006, 01:45 PM

Yeah, I have the big bottle. I'm just not sure exactly how I should run it through.

**Alec** · 05-08-2006, 07:24 PM

You can feed it through the break booster line or feed it through the pcv line.
I kinda do a half and half deal. Right when you are about to run out dump enough in to stall the car. Let it sit 30 min an hour whatever and watch the smoke show

The first time I used it GM called it X66 and it works so well that I thought the neighbors were going to call the fire dept.

If that doesn't solve your detonation you may have a corroded knock sensor. There is a TSB about water getting under the intake and screwing it up. Do you wash your engine a lot?