Engine freeze plug replacement

cdream

New Member
Oct 18, 2014
10
Vancouver, BC, Canada
Boat Info
'86 Sundancer 300 DA
Engines
Two Mercruiser 260
My starboard engine freeze plug popped out. Has anyone put a freeze plug in without pulling the engine out? Any tips?

'86 Sea Ray Sundancer 300DA w. two 5.7 Mercruiser Alpha one 260 Engines.


The boat was shipped from Toronto to Vancouver over the winter and was not winterized.
 
You are most likely wasting your time…The engine will need to come out to replace the ruined parts if it has not been winterized. I have never seen it pop them and not ruin the block. I have heard it can happen, however I would be willing to bet you have BIG problems.
 
You are right. I have also noticed that all four exhaust manifolds are cracked. Fun, fun, fun..................no boating this summer, I guess...............
Do you have any suggestions for parts at a reasonable price?
 
You are right. I have also noticed that all four exhaust manifolds are cracked. Fun, fun, fun..................no boating this summer, I guess...............
Do you have any suggestions for parts at a reasonable price?

Ouch. Cracked manifolds and popped freeze plugs may mean the engine blocks are also cracked. Unless you really know what you are doing, I would recommend you find a trusted marine mechanic and let them sort out the repairs that are needed. You may be looking a couple of new, used, or rebuilt engines. Cross your fingers that the blocks are not cracked. Other things you need to check are your hot water tank, head system and all the interior water lines that feed the sinks etc.
 
Why condemn the engines. OK the manifolds have to go but freeze plugs are easy to put in and cheap.50-50 chance. what have you got to loose?
 
I'm glad I found it before putting the boat in at the marina. I will get a pro to have a look first.
One engine is a "new" rebuild. The other needs some work.
Best to take it one step at a time.
Thanks for the input.
 
The plumbing inside seems okay - it was filled with RV/Marine anti freeze.
I'll replace the visible damaged parts and run them for a bit on a hose. If there is water in the oil, I'll need to take the next step.
Thanks
 
The boat was still in the water when the cabin was winterized in Toronto. The marina was not asked to winterize the motors when it was loaded on the trailer. The boat was brought from Toronto to Vancouver in November 2014. Traveling for a week through icy Canada did the engines in. When I inspected both engines yesterday I noticed the freeze plug was out. This morning I also noticed all four manifolds were cracked. That is about it. I was not there when the boat was shipped and did not notice it when the boat arrived. A lot of hard lessons learned.................
 
If you get water in the oil.......the intake manifold may have broken at the thermostat location/crossover. I also had two freeze plugs pop on my 454 last Oct in a cold snap. Only the exhaust manifolds cracked and I needed new ones anyways. I lucked out! Not so lucky on the 5.7L...hoping it's just the intake as I was told it may be. Fixing the 454 first!
 
Thanks, I'm hoping for the best. There is no need to rush so, I now have time to fix all the other small issues while the boat is out of the water.
 

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