What are the symptoms of a cracked block on a 350 Mag

[Bondo]

Its called brass plugs....

Ayuh,..... Ya gotta know where yer drains are, 'n Use 'em,.....

Air don't Freeze,.....

 

[SkiGuy1980]

Ok...verdict is in. After pluging the core plug and pressurizing the oil started to take on a milky look (yep..... cracked). My mistake was not completely draining (new set up for me... and very different from my 25 y/o 4.3). As I said, I worried about this over the winter when we saw lows in the -35 to -40 range. I think after this that certified winterization is a small insurance policy. Thanks again for all the insight. I appreciate the feedback.

 

[alldodge]

Sure sorry the hear

 

[Boater31]

Unless things are really different where you are at, all mechanics by me make you sign a waiver that they will not be responsible for damage do to winterizeing. When I first got my boat I thought the same way. Had mechanic do it, during winter found out they do it by dunking drive in tank of AF then run it for a while and was worried all winter. First start of Summer water in oil. Got picke with only bad manifolds/elbows (batwing), PO probably new about it and changed oil before I got to see it and mechanic didn't say he saw water in oil during the oil change but different story. Last winter I did it my self using the Merc book for my engine and drive, Don S. stickey on top of this forum and when all drained -100f AF in tsat per the book and had no worries. From now on I will save my winterizeing money and have better piece of mind. YMMV

 

[Scott06]

Sorry to hear that. A new base 350 is 'only' about $3k. If you're reasonably handy it's not a bad swap, I'd replace the exhaust as well. Good luck

 

[Fletch2018]

SKI GUY, will you please let us know what the dealer determined on your motor?

 

[SkiGuy1980]

Fletch2018 - He plugged the blown core plugs and started it up... stopped after a brief run and checked the oil. The oil appeared milky which indicated the block was cracked letting water in. Im not sure what to think about the price he quoted (12500 + ~1000 labor for new 350 Mag MPI, about 7200 for a reman from Merc.). I'm getting a second quote from a Merc dealer in Kentucky that's done work for me before. In either case I'm sick over it.

 

[Bt Doctur]

Find another dealer that eats chopmeat and not filet mignon

 

[Bt Doctur]

New GM 5.7L Vortec 325Hp Mercruiser Bravo Replacement Engine Package*

Application: Mercruiser Bravo1, 2 or 3

Original Replacement For: GM 305 / 350 cu, 5.0/5.7 L Mercruiser

Fits Years: 1988-2012

Engine Specs: Standard Rotation, 1 Pc Seal, Roller Cam, Vortec Heads, Center Bolt Valve Covers, 8 Bolt Intake, 4″ Exhaust, 3 Groove Pulleys, P/S Pump & Bracket, Alternator, Starter, Sea Water Pump, Closed Cooling.

Accessories Needed For Compatibility: Bell Housing, Flywheel Assembly, Engine Mounts & Wiring Harness

 

[Bt Doctur]

New GM 5.7L 260Hp Mercruiser Alpha Replacement Engine Package

Application: Mercruiser #1, MR1, Alpha 1 (Gen 1 and 2)

Original Replacement For: GM 305 / 350 cu, 5.0/5.7 L Mercruiser

Fits Years: 1978-1997

Engine Specs: GM 5.7 L 1 Pc. Seal, Center Bolt Valve Covers, 12 Bolt Intake Manifold, 4″ Exhaust Risers, 3 Groove Pulleys, P/S Pump, Alternator, Starter.

Accessories Needed For Compatibility: Bell Housing, Flywheel Assembly, Engine Mounts & Wiring Harness

 

[Bt Doctur]

and there a whole lot less money about 50 % less

 

[nola mike]

Any reason not to go with a reman short block? I'm seeing $1500 or so for those...
Obviously would have to make sure there's only damage to the block, but $1500 is a lot easier to swallow than $12K

 

[SkiGuy1980]

nola mike - I'll definately go with a reman long block if I go with the local shop. Since the boat is so new (18 hours) I want to stay with a Mercury block. However, I'm not sure why the Mercury reman is so much higher than all the other posts I've seen. Hopefully I get a better price in the morning from my guy in Kentucky.

 

[nola mike]

Well, your "Mercury" block is a GM block, as I'm sure you're aware. AFAIK, only difference is core plugs and maybe headgasket...
What's the relevance of the boat age?

 

[SkiGuy1980]

Age doesn't impact it other than my wanting to keep it like I bought it. I still want to eat though . The only other reman I'm aware of is the Jasper... Talked with the mechanic about trying something other than Merc... he indicated he'd only done one other and wasn't problem free. Gaskets, and Merc bores a consistent 0.040 over. May just have been his luck.

 

[alldodge]

Look at Michigan Motorz, several have pick ones up from them

Yours being an MPI you don't want a non-vortec motor. MM sells Merc remans and there own remons. This one will work for you

http://www.michiganmotorz.com/vortec-marine-engine-1996-current-p-68.html

 

[Bt Doctur]

the trouble with a reman is that you know nothing about the donor motor, engine blocks from salt water do rust so unless its certified a fresh water motor or had fresh water cooling your at risk.
The info in the links I posted are new production and are less than 6K

 

[SkiGuy1980]

My Merc repairman in Kentucky installed new core plugs and ran the engine for 20 minutes - NO leaks! NO water in the oil!! We took it down to the lake and ran 45 minutes of trials (lot of full throttle) and no indication of a cracked block! So relieved!

Of course, now I plan to visit the original repair shop... need to understand why they thought I needed a new engine.