I have a 2000 v6... https://cimg0.ibsrv.net/gimg/ls1tech...fc9fc9a8d6.jpg which has been giving me hydrolock issues on cylinder 4 as discussed here... https://ls1tech.com/forums/pontiac-f...-2k-fbird.html and was written off as a head gasket leak. I am starting to think this is not exactly the problem.
See one day I was going through a car wash and it started running really rough and almost stalled. It only lasted 10 seconds. I've also noticed shes hard to start after it rains allot but this vehicle does not go out in the rain often. Well as I've said I've had to purge cyl 4 due to hydrolock a couple times and thought it was a HG failing. I've never seen any coolant loss and never saw any water vapor from the exhaust until the other day!
I was getting her ready for spring and, as I do through out the winter, started her up to run a little but this time decided to wash while she was warming... Holy $h1T, you had to see it.. It was like a Penn and Teller show. It was literally like a hollywood smoke machine. Bellowing steam from the exhaust. I stopped rinsing it and the magic show went away. I had to see it again so I started rinsing. I systematically started watering my car from bottom to top. When I got to the passenger side windshield was when it happened again! Smoke show! WTF???? Anyone? Please anyone... try to explain this to me.

 

Water might be dripping down through the cowl and onto the side of the head

 

If it's steaming out of the exhaust the only logical explanation is water getting sucked into the engine somewhere along the intake tract. To help locate the issue you could leave the engine off and try to washing the car as you were before and after a few minutes open the hood and see where the water is hitting. If you ever try to start the car in the future and you suspect it's hydro locked then pull spark plugs and turn it over to force the water out, Trying to crank over a hydro locked engine can end in bent/broken rods. If cylinder 4 was the issue before it's probably a good place to look.

 

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