Procedure for ensuring no antifreeze in cylinders of 3YM30 before cranking?

Apr 8, 2011
768
Hunter 40 Deale, MD
I am concerned that there may be antifreeze in the cylinder(s) of my 3YM30. The engine has not been started since the event which led me to suspect this might be the case (and I'm probably being hyper vigilant here), so I want to ensure there's definitely no antifreeze in the cylinders before I try to start the motor so I avoid any damage. I've done a bunch of reading and think this is the right procedure to clear the antifreeze and get the motor back to normal. Am asking for anyone's thoughts on this:

1. Leave raw water seacock closed
2. Drain water lift muffler
3. Crank engine 2-3 rotations by hand at crankshaft CLOCKWISE
4. Crank engine briefly with STOP button engaged to prevent cylinders firing
5. Open raw water seacock
6. Start engine and run briefly
7. Shut down engine and check oil for antifreeze
8. Change oil and filter if antifreeze observed
9. Repeat steps 6-10 until no antifreeze observed in oil
10. Run engine under load to operating temperature to evaporate any antifreeze in system
11. Don't do whatever I did to get antifreeze into the cylinders again.
 
Dec 8, 2020
1
Catalina 30 seabrook marina
what was the event that leads you to believe coolant is in the cylinders? If the engine can be accessed and turned by hand, simply turning it in the direction of operation will tell you if its hydro-locked.
 
Dec 14, 2003
1,393
Hunter 34 Lake of Two Mountains, QC, Can
Your list is good. But the likelyhood of getting antifreeze in the cylinders is almost non-existant. It would mean something happened to the engine itself caused by something like overheating or other problem. However, if you did cause hydro-lock, it would be with water being admitted through the exhaust valves by cranking engine too long with raw water seacock opened and engine not starting. What you could do then to expell that water is remove the air filter, decompress the 3 cylinders and turn by hand (clockwise). After no more liquid comes out, get some fogging oil and while turning spray some into the air intake. Then keeping the engine decompressed, turn it with the starter for a few seconds (best to disconnect intake hose at impeller to make sure no water is admitted) while spraying a bit more fogging oil in the air intake. You can then engage compression levers and start engine, running no more than 5 or 6 seconds and shut down. Then reconnect intake hose, open raw water seacock and go from point 6 in your list. If no damage has been done you should be good to go. Don't ask me how I know LOL. Good luck.
 
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Apr 8, 2011
768
Hunter 40 Deale, MD
Your list is good. But the likelyhood of getting antifreeze in the cylinders is almost non-existant. If you did cause hydro-lock, it would be with water being admitted through the exhaust valves by cranking loo long with raw water seacock opened and engine not starting. What you could also do to expell that water is remove the air filter, decompress the 3 cylinders and turn by hand. Get some fogging oil and spray some into the air intake after no more liquid comes out. Then keeping the engine decompressed, turn it with the starter for a few seconds (best to disconnect intake hose at impeller to make sure no water is admitted) while spraying a bit more fogging in the air intake. You can then engage compression levers and start engine, running no more than 5 or 6 seconds and shut down. Then reconnect intake hose, open raw water seacock and go from point 6 in your list. If no damage has been done you should be good to go. Don't ask me how I know LOL. Good luck.
Appreciate the input - thanks. Unfortunately the 3YM30 doesn't have decompression levers. Am hoping I can turn the engine over at the flywheel slowly with a wrench. The service manual does say to do this when you're checking for injection timing, so technically its possible. Just don't know whether its possible without disconnecting bits of the injector system.
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
you should be able to turn it over slowly with a wrench. Make sure the fuel is OFF ( pull the cutoff/stop) to the engine because even turning it slowly can cause it to fire .. and make a mess of your wrist/arm.
 
Apr 8, 2011
768
Hunter 40 Deale, MD
you should be able to turn it over slowly with a wrench. Make sure the fuel is OFF ( pull the cutoff/stop) to the engine because even turning it slowly can cause it to fire .. and make a mess of your wrist/arm.
Did not know that. Will do.
 
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Jul 7, 2004
8,402
Hunter 30T Cheney, KS
If you "Leave raw water seacock closed " while you run your engine you will overheat and/or burn up your impellor.
Have you fixed the problem that caused antifreeze to enter the engine? Was it a Darwin moment?
 
Apr 8, 2011
768
Hunter 40 Deale, MD
If you "Leave raw water seacock closed " while you run your engine you will overheat and/or burn up your impellor.
Have you fixed the problem that caused antifreeze to enter the engine? Was it a Darwin moment?
Thanks, raw water would only be closed for a few seconds to prevent any additional water from entering while what's in the system gets pumped out. I'd def open that very quickly to prevent damage to the impeller.

Darwin moment - good way to put it. I removed the raw water pump to replace it as it started leaking this year. I thought I'd winterize the raw water system by pumping 3 gallons of antifreeze with a drill pump through the raw water intake, assuming it would exit the exhaust. I haven't replaced the raw water pump yet, so I haven't restarted the engine, but i'm concerned after doing some reading that the pressure from the drill pump wasn't sufficient to force the antifreeze out the exhaust system, and I may have caused the system to fill up to the exhaust elbow and backflow into the engine. I don't know if I'm being overly cautious, but it appears the absolute worst thing I could do is to just try to start the engine without determining if there's water in the cylinders first.
 
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Dec 14, 2003
1,393
Hunter 34 Lake of Two Mountains, QC, Can
You can empty into the bilge the section of the exhaust by disconnecting the exhaust hose below the elbow. In the manifold and in the exhaust hose is where water remains when engine does not start, and from there gets sucked in through the exhaust valves. If too hard to undo hose from elbow because it has been cooked there, disconnect at the waterlift (muffler). Also, there is generally a petcock right on the manifold, somewhat near the elbow. Opening it should empty the manifold. If nothing comes out, run a tiny screwdriver or a wire in it as it might be plugged up by sludge. BTW, Justin is right you do not want to run the engine dry. But it will not cause any issues if you do it no longer than 5 or 6 seconds. Above 10 seconds you might desintegrate the impeller and longer than that is seriously asking for eventual major troubles. One last thought: Kloudie is right with his advice about pulling the cut/off when turning your engine but I would use a ratchet rather than a wrench. If engine was to start, ratchet would likely click freely and thus chances are less of being hit hardly by the wrench locked onto the big crankshaft nut.
 
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Apr 8, 2011
768
Hunter 40 Deale, MD
You can empty into the bilge the section of the exhaust by disconnecting the exhaust hose below the elbow. In the manifold and in the exhaust hose is where water remains when engine does not start, and from there gets sucked in through the exhaust valves. If too hard to undo hose from elbow because it has been cooked there, disconnect at the waterlift (muffler). Also, there is generally a petcock right on the manifold, somewhat near the elbow. Opening it should empty the manifold. If nothing comes out, run a tiny screwdriver or a wire in it as it might be plugged up by sludge. BTW, Justin is right you do not want to run the engine dry. But it will not cause any issues if you do it no longer than 5 or 6 seconds. Above 10 seconds you might desintegrate the impeller and longer than that is seriously asking for eventual major troubles. One last thought: Kloudie is right with his advice about pulling the cut/off when turning your engine but I would use a ratchet rather than a wrench. If engine was to start, ratchet would likely click freely and thus chances are less of being hit hardly by the wrench locked onto the big crankshaft nut.
Excellent points and sensible precautions. I’ll post after I get thru this. Appreciate the input from everyone.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
AF/Water is not compressible. If there is liquid in the cylinders you will need to remove the injectors, unless it has glow plugs. Get this liquid out ASAP.. You'll know if there is liquid in there if you rotate the engine by hand. Just be sure the stop cable or solenoid is set to OFF...
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
AF/Water is not compressible. If there is liquid in the cylinders you will need to remove the injectors, unless it has glow plugs. Get this liquid out ASAP..
That's what I was concerned about as well. Especially high compression diesels!
 
Sep 15, 2013
707
Catalina 270 Baltimore
Maine Sail beat me to it. Pull out the glow plugs. That will decompress the cylinders and give the water a way out. They are easier to pull than injectors.
 

Tedd

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Jul 25, 2013
745
TES 246 Versus near Vancouver, BC
3. Crank engine 2-3 rotations by hand at crankshaft CLOCKWISE
I'm not sure what you mean by clockwise, but cranking the engine opposite to it's normal direction of rotation is a good idea. That's commonly done before starting engines where there's a risk of pooling liquid in the cylinders, such as radial airplane engines. (Fuel can pool in the bottom cylinders.)
 
Apr 8, 2011
768
Hunter 40 Deale, MD
So to follow up - good news, and some lessons:

The Good News
I pulled the injectors on the 3YM30 (more on why those and not the glow plugs below), rotated the flywheel and only air came out of the cylinders. Reinstalled the raw water pump and now I'm just awaiting parts to put the motor back together. While I'm awaiting parts and have the injectors out of the engine I dropped them off at a diesel shop to have them checked out and cleaned up as necessary. No way of knowing how long its been since they were checked out since new in 2009 (though I did see tool marks on the injector bodies), so figured with winter layup this is a great time to get that done. With any luck I'll get the parts in, reinstall the injectors, bleed the fuel lines, and we should be off and running.

Lessons
- Don't use a drill pump to push antifreeze through your exhaust system as it doesn't have enough pressure to do so successfully
- Injectors are easier to pull on a 3ym30 than glow plugs. Two of the three glow plugs are buried in the engine and not accessible without an uncomfortable (for me) amount of disassembly. I could see the plug wires, but couldn't even SEE two of the glow plugs.
- In order to get a wrench on the aft most injector I had to take the wire off the aft most glow plug - which is fairly accessible. Teeny tiny nut and similarly sized washer held the wire on. Very delicate operation - especially when contorted through an engine access hatch with only one arm available. A very slim socket extension saved the day, and lots of slow movement.
- The fuel pump injection lines from the fuel pump and injectors themselves were really no problem to remove. The real problem was the return line, which is secured by a top nut onto each of the injectors. Since the return line is made up of soft metal tubing you have to be VERY careful not to twist it when removing the top nut, which wants to torque the return line as the injector it is connected to turns in the engine block. To prevent this you are supposed to put a wrench on the injector, and hold it still, while you put a wrench on the top nut and twist it off. Yeah, good luck with that. The top nut securing the return line was WAY tighter than the injector in the engine block, and there was absolutely NO way to get any tool available to mere mortals on the sides of the injector due to the engine block recess being so close. After twisting the metal return lines enough that I realized they were probably compromised I took a pair of wire cutters and snipped the tubing off close to the injector. Then it was a simple matter of backing out the entire injector with a wrench. The return line is a $62 part I'm happy to replace. If anyone has a better idea I'd be very glad to hear it. I'm having the diesel shop loosen the top nut from the injector when they clean them up as I cannot with hand tools. Sheesh. I'm giving serious thought to just how to reinstall without torqueing the NEW return line.
- My engine is pretty clean, but as soon as I started torqeuing and snipping return lines and putting wrenches on painted fuel lines and injectors little bits of paint flakes were everywhere. I used a shop vac to get as much of that as I could to prevent it from falling into the cylinders when the injectors came out, and shop vacced the injector hole as well, just to be safe. Then stuffed clean and oiled shop towels into the injector holes to prevent rust while the injectors are out.
- If you have an average set of tools you'll likely expand it during this mechanical work. The wrench and socket sizes required are metric and larger than the "standard" toolkits provide. I bought a set of metric open and closed end ratcheting wrenches that included a 17mm which I needed for the top nut on the injectors. The actual injector body screwed into the engine block is even larger than that, I want to say around 22mm. That's 1/2" socket territory, and you'll need an extension and any adapters for your tool set to get that on there if the top part of the injector comes off during removal.
- Also, to put the injectors back in you'll need to replace some consumable gaskets. If you look on the parts diagram you'll see them. They're just a few bucks apiece (the injector shop will probably replace them, but I have them ready).

I hope not to have to do this again, but I did get to work on parts of my 3ym30 I've never touched, which I'm enjoying. It seems like a simple engine to work on, but access is an issue, both from an engine bay perspective as well as the way the engine is assembled. Probably way easier on the factory floor when they put it together. Anyway, thanks for everyone's help on this. Appreciate the assist.
 
Apr 8, 2011
768
Hunter 40 Deale, MD
Final update:
Installed rebuilt injectors, new fuel return line, raw water pump, and after four 5-second cranks (with the raw water seacock shut) the engine started and ran normally (raw water seacock opened as soon as engine started). No bleeding required. Total cost was under $300 (not counting a few tools I had to buy):
$200 for rebuilding/testing injectors
$62 for new fuel return line
$20 for various crush washers for injectors and fuel return line

The one thing I wasn't able to do was pull out the injector protector nozzles from the block. I talked to a mechanic and he advised me it was fine to leave the old one in if its undamaged and difficult to get out. Just put a new crush washer on top after removing the old one and torque the injector body properly. If no fuel leaks, you're good. If fuel leaks, then you'll have to get it out and replace. Luckily no fuel leaks.

Thanks again for everyone's suggestions. Learned a lot, which was really enjoyable.