I’m helping a friend and need some advice. He parked his Plymouth for the winter with straight water in the engine, no coolant at all. By the time he remembered it didn’t have antifreeze it had frozen enough that the waterpump wouldn’t turn and the core plugs in the front of the block got pushed out. It’s a 360 mopar engine. we had a few warm days this week and it thawed out. We tried to temporarily drive the plugs back in and circulate antifreeze. Hopefully over the holidays we can tow it to a friends house where we can get it on a lift. The coolant mostly ended up on the floor but the engine did fire up and ran fine and there is no water in the oil. first, is there any chance the engine will survive this or do we start shopping for a replacement block. I’m not familiar with Mopar engines at all, if the block is cracked are there common spots we need to check.
I've seen a few SB Mopars crack in the lifter valley after freezing. If theres no water in oil and no visible leaks outside you are good to go.
Can’t speculate on weather it will be ok or not. Pressure test the cooling system may give you a clue. But only a clue.
If the core plugs are pushed out there's a good chance the block is cracked, usually in the lifter valley as said above. I wouldn't try to run it and pressurize the system with hot water until a pressure test of the cooling system is done. The plugs are used and may not hold if any pressure builds up. Hot water dumping out of a hot engine isn't my idea of a fun time. New core plugs, test for leaks and if OK then you should be good to go.
When it comes to blocks freezing it is hit and miss. Some push the freeze plugs out and are good to go with no other damage. Some crack in places you can’t see and may or may not push out the freeze plugs. How cold it got and for how long is a big factor. But as mentioned above, put the plugs back in after carefully checking for cracks around the plugs. If you don’t see any cracks and you don’t see water in the oil run a pressure test on the cooling system. Even a slight pressure leak could mean serious problems. Find the leak and visually verify if there are cracks where it is leaking.
Yes, pressure test for sure. The SBC in my avatar coupe has a freeze crack about 3 in long right behind the motor mount(external). It weeps a little, but I've been driving it like that for years.
There are also core plugs on that 360 at the back of the motor, inside of the bell housing or trans, and just above the pan rails on both sides of the block. If it froze hard enough to pop out the core plugs, it has frozen hard enough to take out any weak point in the block as well. I've seen a few that popped the core plugs out that didn't crack the block, but not many. Be aware that not all the possible crack locations are visible on the outside of the motor. Anyplace coolant (or in your case, water) sits inside of the block and heads is a possible crack producing area.
The guy that owns the car is coming over for drinks and I’m going to try talking him into buying a 340 I found on marketplace. Maybe if I show him the video of my fox body running a faster ET than his Plymouth it will encourage him lol
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