98 4.3L Vortec problem

[Mwatsontechtraining]

Looking for some help.
Just bought a 98 proline power b a 4.3 Vortec.
ran fine for the first 45 mins, acted up and died while under power. Engine temp and oil pressure good. I started back up and ran 5 mins seen smoke coming out of the engine cover. I shut down open up the cover and oil was all over the top of the manifold and coming out of the breather.
Never over hearted and good oil pressure. What’s your thoughts? Intake manifold gasket?

 

[Bondo]

Ayuh,

Looking for some help.
Just bought a 98 proline power b a 4.3 Vortec.
ran fine for the first 45 mins, acted up and died while under power. Engine temp and oil pressure good. I started back up and ran 5 mins seen smoke coming out of the engine cover. I shut down open up the cover and oil was all over the top of the manifold and coming out of the breather.
Never over hearted and good oil pressure. What’s your thoughts? Intake manifold gasket?

Ayuh,.... Welcome Aboard,..... My 1st guess is a cracked block, from improper winterization,.....

You just bought it, did it get any sorta look-over before ya splashed it,..??

 

[Rick Stephens]

Most common location for 4.3L to freeze crack is in the lifter gallery. This pumps water into the oil while all other mechanical operation is normal. Won't show on compression test. Only test you can do is cap off all the exiting water hoses and pressure test the cooling system. My bet is you hear a hiss under the intake.

 

[Lou C]

Yep could be a cracked block/heads or if it has the Merc V6 one piece manifolds, they can fail and put water in a cyl and in the oil.
Was the boat stored in freezing temps? Winterized properly?

 

[Scott06]

Most common location for 4.3L to freeze crack is in the lifter gallery. This pumps water into the oil while all other mechanical operation is normal. Won't show on compression test. Only test you can do is cap off all the exiting water hoses and pressure test the cooling system. My bet is you hear a hiss under the intake.

Only other place to check in addition to where rick said is in the water cross over under the thermostat, but that wont help you if no draining was done.i think there is separate plug in the front of the intake on 4.3 s that can get missed if the restof the engine was properly drained

 

[nola mike]

Only other place to check in addition to where rick said is in the water cross over under the thermostat, but that wont help you if no draining was done.i think there is separate plug in the front of the intake on 4.3 s that can get missed if the restof the engine was properly drained

There is a separate plug, but there is no mention of it in the merc manual. I removed it twice last year, completely dry. Didn't remove it over the winter. I don't see where the water would hide if you remove the hose near the tstat. (But yeah OP, sounds like a cracked block )