Seafoam

willscary · July 17, 2004

Well, after reading all of the "piston knock" pinging posts on the net that I could find, I accepted Chevrolet's 6yr/100,000 mile extended warranty. As I stated in a prior post, I have heard this noise on all of our company trucks, and they still run great with no oil usage after well over 100K miles. We have about a dozen of these trucks, and as timex used to say..."they take a licking and keep on ticking"!!!

Anyway...I decided to use Seafoam to clean the motor after the guy at Chevy customer service blamed the noise on minimal carbon build up. Today I sucked a can of it through the PCV vaccum hose into the manifold. The motor did not stall out, but slowed and ran rough. Towards the end I let it go quicker and then shut off the well warmed motor for a half hour. It took several seconds to refire the motor after it sat, and a white smoke plumed from the exhaust, although not nearly as much as I had expected after reading others who posted on this subject.

I limped it out of the driveway and down the road across from my house. It is a two mile long straightaway with very few homes. I pushed the truck hard and it began to smooth out. It took about 10 minutes of hard acceleration and slowing down to clear the motor of the seafoam.

I brought it back to the driveway and left it sit for about 6 hours. It is now about 7PM and it has cooled down considerably here. I fired it up and I guess I am happy with the results. The motor had a very slight vibration at warm idle (at a stop sign, etc.) that has vanished. The motor is smoother (it was very smooth and quiet except for the pinging, and now it is even more so). The pinging is still there at acceleration, but is only MAYBE 20% as loud as it was before.

This was top engine only. I will add a bit to the crankcase and the rest to the gas tomorrow. In about 200 miles I will be needing gas, and I will change oil at that time. I am considering switching to synthetic, but am not quite yet sure if I should.

This is the first time I have used Seafoam in an auto. I have used it on my boat motor with great results, and now I am sure it helped my pinger quiet down.

One more observation...my warm idle was about 500-550 rpms on the tach. Now it is about 100 rpms faster. I know the Seafoam literature says this will happen, but I am not sure why or how. Any insight on this would help.

asepgrad98 · July 18, 2004

Sounds like the seafoam worked well. I dont think that you should add ANYTHING to the oil. It could cause increase wear IMO.

willscary · July 18, 2004

OK...I just got back home. My truck still has the ping under moderate acceleration, but only over about 2300 rpm, where before it was anything over about 1500 rpm. This means it is dead silent and smooth for most all in-town driving! YAHOO!! As I said, the ping or knock is only about 20% of what it was (very subjective), and is really about the same as the brand new crew cab I drove with only 6 miles on it.

hawghunter · July 19, 2004

Where are you finding the Sea Foam ? I have looked in Kragen, Pep Boyz etc... I live in So Cal. I really want to run it through my wifes 98 Cavalier. Any suggestions?