Took the boat out (96 Cobalt 4.3), ran fine all the first day but as I was coming in it started missing like a plug was out. I didn't think much of it - we were in FL and normally from PA on vacation - started fine the next day but soon started to miss. Figured I would see if it cleaned up after running some, seemed to run decent but on a WOT run was down 800 rpms. Got it to the dive site and when I shut if off it wouldn't restart.
Water in the engine on one bank - oil looked clear on the dipstick though and not high on the stick. So we towed it in and cranked the water out and sprayed some penetrating oil in the plug holes.
Figured rotted manifold or riser - 3-4 yrs old but not used often - so replace that side and tried it with muffs on. Still water coming in so we pull the plugs and fogged as best I could until I got home to tear it down.
Appears to be a cracked head - looks like crack between plug and valves area.
So I have both heads off, can't see any damage to the pistons - obvious damage anyways. sprayed the lifter valley out with carb cleaner and then fogging oil. I will let that drain and finish draining the oil (which is milky and is throughout the motor) and change it and the filter - tomorrow. I drained 1/2 of the oil the day after it happened which got the really watery part out.
Question is
A. Is it worth it to get the good vortec heads and a manifold?
B. What year heads work and/or better?
C. What is all needed to convert?
D. Just replace with what is there?
E. any other input or ideas on what to do now?
Thanks for any answers and sorry for the novel
Water in the engine on one bank - oil looked clear on the dipstick though and not high on the stick. So we towed it in and cranked the water out and sprayed some penetrating oil in the plug holes.
Figured rotted manifold or riser - 3-4 yrs old but not used often - so replace that side and tried it with muffs on. Still water coming in so we pull the plugs and fogged as best I could until I got home to tear it down.
Appears to be a cracked head - looks like crack between plug and valves area.
So I have both heads off, can't see any damage to the pistons - obvious damage anyways. sprayed the lifter valley out with carb cleaner and then fogging oil. I will let that drain and finish draining the oil (which is milky and is throughout the motor) and change it and the filter - tomorrow. I drained 1/2 of the oil the day after it happened which got the really watery part out.
Question is
A. Is it worth it to get the good vortec heads and a manifold?
B. What year heads work and/or better?
C. What is all needed to convert?
D. Just replace with what is there?
E. any other input or ideas on what to do now?
Thanks for any answers and sorry for the novel