3 Freeze Plug
Magdalena Liendo
Also known as core plugs, freeze plugs play an important role in protecting automotive engines from cold-related damage. Unfortunately, though, many drivers rarely or ever check their vehicle's freeze plugs. While freeze plugs often last for hundreds of thousands of miles, they aren't immune to failure. And if your engine's freeze plugs fail, it could lead to catastrophic damage that's both costly and difficult to repair.
Freeze plugs are small, cylindrical-shaped plugs that are used to fill the passages in an engine created by the sand cores. During production, passages are created in engines that allows for the removal of casting sand. To fill these passages -- and therefore protect against coolant leaks -- automakers use freeze plugs.
In the past, plain water was used to cool combustion engines. While effecting at removing heat, plain water is susceptible to freezing. When the water coolant inside a vehicle's engine froze, its freeze plugs would push out. Automobiles today no longer use plain water as coolant. They use a combination of water and antifreeze. Nonetheless, you should still use caution to protect your engine's freeze plugs from failure.
Freeze plugs typically fail by freezing. This isn't necessarily a bad thing, though. Freeze plugs were originally used to protect engines from cold-related damage. If the coolant inside an engine freezes, it may cause the block to crack. Water expands as it freezes, and the pressure created by this expansion can cause cracks to form. Freeze plugs prevent this from happening by allowing the frozen water to expand out the plugs' passages.
After a freeze plug has failed, however, it must be replaced. Freeze plugs fail by popping out. Once a freeze plug has popped out of the engine, it will create a breach in the cooling system. In other words, coolant will leak out your engine through the freeze plug's passage.
To prolong the life of your engine's freeze plugs, be sure to use the correct coolant as recommended by the automaker. Don't just fill the radiator with water. Even if it's distilled water, it probably needs a specific amount of antifreeze as well. If you only use water -- or if you don't use enough antifreeze -- your engine's freeze plugs may pop and fail. In addition to using the right coolant, consider getting your vehicle's cooling system flushed at least once every two to three years. By proactively maintaining your vehicle's cooling system, freeze plugs are less likely to fail.
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what motor is in your boat? assuming its a monsoon or 8.1, if your mechanically inclined just buy a block from a local machine shop. most will have the gm 350 blocks laying around. have them machine it up nice for ya, and swap over the parts. or you can buy a bare block ready to go from www.gmperformanceparts.com for about $850
Having a "freeze plug" (it's actually a casting plug) come out means that the water expanded so much in your block it had the pressure to pop it out, which is usually enough pressure to crack the block in the valley of the intake manifold.
Replace the casting plug (they are just pressed in, use a rubber mallet and a block of wood to reinstall) and fire it up in the water, don't leave the boat launch until it warms up. Monitor the oil condition and look for a frothy milk shake looking oil to start. if it starts, stop the engine. It's a huge mess to clean up so if you have a cracked block the less you run it the easier it is to deal with replacing the motor.
Make sure the engine is marine, I've had so many customers use automotive blocks and after 20 hours you end up burning something up in the motor and starting all over again. Marine engines are built to run at 4-5K RPMs all day long and handle the load no problem. I always suggest staying with a Indmar block whether it be new or re-man because the engine is calibrated around all of it's components. If you change something it might change the performance of your engine drastically. Which can be a big bummer because you can't change the calibration on Indmar's ECM controllers.
I researched this a short while ago using the casting #s on the back of the block. It seems that the marine block is the same casting as the gm truck or performance. The numbers cross over directly. Using these numbers, you can make sure you get the "marine" block at an automotive price.
Actually i was going to pull the plugs and and turn the motor over and see if i get any water spitting out of it.. I will hook it up to a hose. If not then i will try start it and run it.. I did drain all the hoses and plugs except for the knock sensor. I could not get it out. I thought i would have gotten all the water out
Here at Bake's we don't buy a bare block, we purchase a assembled long block and leave the engine assembly to the manufactures at GM. There is not a good enough machine shop in our area that i would trust building a block for our boats. Plus by the time you go that route there won't be much of a cost difference. Yes you do pay more going the Indmar / Marine route, but it's worth it.
The difference in a automotive block vs. a Marine is not the block itself, it's all the components it's built with. The main issue is the crank bearings are sized different for a engine that runs at 240 degrees vs 160 degrees. So when you start running at 3-5K rpms on a tighter bearing at a lower temperature you start creating a lot of excessive heat eventually locking the the bearing up. Bearings are not the only difference,
Yes when you are running a business it is different. In the automotive shops it was the same way as no one want to have any problems to come up so it is by FAR easier to have the customer purchase a long block. There are fewer problems this way. However, if the O.P. needs to do this on a budget and has the skills it is going to be a better deal to buy an new GM block. The bearing clearances can be set at the machine shop.....we have used .0022" on racing engines very successfully and is often thought of as the optimal clearance.
I guess bottom line is if you have to skills you can do it yourself and save $. If not, you are way BETTER off buying a long block as Paul suggests. Heck, I have the skills and would still think buying the long block just to avoid the work
I would research my nearby hot rod clubs. These guys are often the 50 year olds plus and are more than glad to share their accumulated knowledge. They will know of a local engine rebuilder that does good work. Often at a very good price.
I'm no longer a hot rodder having switched to Porsches instead. We have two shops locally that rebuild our older Porsches at a reasonable price. Money is tight and those specialty shops are slower now.
The added benefit is that once the local rebuilder examines your block he will know what bearings and block you need. And you may have a chance to build in some additional horsepower and torque while you are at it.
I know that's why i said it was a good price. I was asking if you are only looking for long blocks, or are throwing the option of buying just a block and swapping you internals into it yourself. That's what I would do. If you are thorough, careful, and patient you can build a motor yourself. My wifes car just rolled over 20k on the rebuild I did after she blew the motor up with a blown rad hose. We had a long talk about the dash dummy lights and ignoring the smell of coolant. She insisted she thought it was the car in front of her after driving miles down the highway and wasn't sure why the temp gauge had been pegged the whole time.......Doh!