Knocking after seafoam

Ask our auto mechanics for help to all your GMC truck questions.
Post Reply New Topic

Knocking after seafoam

Unread post by Guest » Wed Nov 20, 2019 9:08 pm

I used seafoam about two weeks ago but did not have engine running I just poured it I to the hose from intake then I tried to start it wouldn't. Until I realized it could possibly hydrolocked so i took all my plugs out and turned the harmonic balance to get out the seafoam that remained. My truck started right up..but is now knocking. Could it be because I still have seafoam in my cylinders? My oil is fine.

User avatar
Posts: 2288
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: Knocking after seafoam

Unread post by carriedi » Thu Nov 21, 2019 11:53 pm

there is a possibility that there is engine damage from being hydrolocked. Piston damage, wrist pin damage or connecting rod damage can happen when the starter starts to spin up and then hits a cylinder full of a liquid. For all practical purposes liquids don't compress. If you just get a lock up that would be nice. Sometimes the engine starts to spin and you get the engine momentum going, it hits pretty hard and things get damaged.

What kind of knock do you have? Is it like a lifter knock? Rod knock? Piston slap noise? Engine ping? Does it get louder with engine speed or load?

Post Reply New Topic
  • Similar Topics
    Last post