I seafoamed my 150k LT1 caprice because it was hesitating a little on start up. I did the standard bottle in the tank and 3/4 to half down the booster line. I kept it running while I was pouring most of it then let it die and walked away. I came back 25 min later, cranked it over and boom went the motor. I heard a loud bang and she locked up really good. Anyone have any ideas on what could have caused this?

 

Leaving it in there for 25 mins let too much accumualte in the cylinders.

 

damn dude your not sopposed to put 3/4 of the bottle in your booster line. At most you should only put about 1/3.

 

^^thats what i thought

 

I thought it was half. Half for the crankcase, half for the upper intake. Then a nice oil change.

 

I've put a whole bottle in my booster line slowly, then put 1/3 in FAST and let it die. Waited 30 mins and it smoked like hell on startup and everything seems to be fine and dandy. Your 150k mile LT1 was most likely on its way out already...

 

It sounds like you hydrolocked it. A liquid cannot be compressed..so if there was any liquid seafoam in the cylinder(s) when you tried to start it, you prolly broke/bent a rod or something. Next time if that happens..take the spark plugs out, and crank it over a few times..this will blow out any liquid that is in the cylinders. good luck

 

yea def sounds like you hydrolocked it. i just seafoamed my 150k ls1 and it smoked something wicked on start up but no bang. i was under the impression though that out of the half bottle reserved for the vacuum line only 1/3 of THAT amount was suppose to be rapidly dumped in. i think you had too much seafoam sitting in your cylinders for too long. the only other thing that might haave happened was when you poured the other half bottle in the crankcase you did it whie the motor was at temp and possibly harmed something.

 

I never put any in the crank case and the engine was running up until the very last min. I kept it running until I dumped the last maybe 8 oz in. What I think I saw out of the corner of my eye was smoking comming from the pass side exhaust manifold. I guess that could have been a leak but I'm going to tear down the top half of the motor tonight and see what she looks like. I have a ton of replacement parts for this car.

If anyone is looking for any LT1 engine parts or Caprice replacement body parts odds are I have them, just drop me a line.

 

man, this is not the first time i have heard something like this happening with seafoam.

 

If hydrolocking is a possible side effect of using seafoam then forget it...

 

+1 to that.

 

If I remember correctly it says on the can not to let the engine stop while slowly feeding the Seafoam into a vacuum source. So pretty much like everyone else had replied, the cylinder/s filled with a liquid, engine tried to compress liquid and bad stuff happened.

 

Another LT1 bites the dust due to Seafoam....you shouldnty have let it stall out, I used a spray bottle to slowly soak into the cylinders. Only 1/3 of half the bottle. Mine still locked up, and apon changing plugs on driver side and draining that crap out, putting in new plugs-she fired right up after a few tries. So after a few spun rod bearings later I am totally against Seafoam or any foreign liquid of any kind. Its way too risky, some have had awesome results...others not so much. Its pretty much the same as Vegas as far as Im concerned.

 

Was thinking about seafoam, not anymore...thanks for posting this.

 

I think I will try seafoam in my gas - and in my oil - but im not trying that last step..

 

Isn't Seafoam 100% pure petroleum so how culd it hydrolock?

 

I ran seafom through my LS1 several times already to clear all the carbon residue out of it. I never had anything like this even remotely happen. I followed the steps in the stickey and everything worked out perfect. I have removed all the plugs and it seems it was loaded with seafoam. I'm going to run it a few times with no plugs, replace them all and try from there. I know this car was already doomed, but I tried. I guess we'll find out what happens when you use seafoam incorrectly because this car cant break anymore.

 

And flammable, so if anything it seems like it would just ignite along with your fuel mixture.

 

Flammable or not..a liquid cannot be compressed. Gasoline can cause a motor to "hydrolock"..It doesent necessarily have to be water.