#1
IP: 174.115.32.21
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Thermostat & Winterization Question
Just read the MMI write-up on the A4 cooling system and realized I hadn’t really understood how it works, and still have some questions...
https://moyermarine.com/nljune2018/ This has raised a few concerns about my winterizing approach. For the last 3 seasons I’ve been winterizing my late model A4 from MoyerMarine with raw water cooling by: - driving the engine for about an hour to warm it up - closing the raw water intake seacock and racing the engine for 2 seconds before shutting it off to evacuate as much water as safely possible - pulling the 3 drain plugs and draining the raw water strainer, then reinstalling the plugs - drawing in a gallon of antifreeze - closing the bypass off for about half the gallon to force glycol through the block - once again pulling all 3 plugs to check for solid pink - then drawing in a second gallon of antifreeze, also half straight through and half with the bypass closed off Based on my newfound understanding of the cooling system, is there a risk with this approach that an insufficient amount of antifreeze will make it into the bypass section of the cooling system (between the thermostat and the T-fitting)? My thinking is that with the warm engine, the thermostat would be open forcing antifreeze to pass though the engine block, limiting flow through the initial part of the bypass loop, and possibly trapping some water. This leads me to a second question - if the engine is cold and I close the bypass hose valve (right before the thermostat), would this stop the flow of cooling water entirely, or would the thermostat still allow water to flow through it from the block? Lastly, how is this linked with the MMI A4 manual recommendation to remove the thermostat during winterizing, and in particular, is it really needed when you can close off the bypass loop and force antifreeze through the block? |
The Following User Says Thank You to whatjigg For This Useful Post: | ||
TimBSmith (10-18-2020) |
#2
IP: 24.152.132.140
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In my area we do not need to winterize so my comments here are not a result of experience. However, considering the fatal risk to the engine of improper winterizing I recommend following Moyer Marine's protocol to the letter. This is not the place to get creative and freelance. If Moyer's protocol says remove the thermostat, then remove the thermostat.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#3
IP: 24.114.102.208
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Thanks for the suggestion, agree proper winterization is critical, which is the reason for my questions.
The procedure I’ve been using is what my sail club’s engineer follows, and he does 200+ boats per season here in Ottawa/Canada where temps can drop below -30°C. |
#4
IP: 23.28.232.191
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I'm with Neal on this one. I think it's probably fine to leave the thermostat in if the bypass valve before the thermostat is closed while flushing with antifreeze. That being said, I always take the thermostat out because, as Neal stated, the downside of being wrong is too painful. Also, removing the thermostat yearly keeps the respective thermostat body studs and nuts clean so I know I can access the thermostat without difficulty in the future.
I don't know what quantity of antifreeze is sufficient, either, but I use more than 2 gallons. The amount needed would vary from boat to boat depending on the exhaust configuration, but I always run 4 gallons through, which gives me enough time to simultaneously squirt fogging oil through the flame arrestor and into the carb (have to clean the arrestor prior to launching next season). I always drain my water lift muffler and make sure it's mostly antifreeze coming out.
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Mark Smith 1977 c&c30 Mk1 hailing from Port Clinton, Ohio |
#5
IP: 24.152.132.140
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Quote:
It's possible your club engineer is fully knowledgeable but also possible he's not. We don't have to wonder with Don Moyer. Ultimately it is your boat, your choice and your risk.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#6
IP: 205.193.94.40
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If I am to remove the thermostat, what's the easiest way to do it? My engine is exactly like this one...
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#7
IP: 165.225.20.157
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2 bolts obvious on thermostat, 2 on flex hose. A serious session of jiggling on the small piece of hose required to lift housing
Be sure to have Permatex and the right gasket
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Surcouf A nostalgic PO - Previously "Almost There" - Catalina 27 (1979) |
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whatjigg (10-19-2020) |
#8
IP: 205.193.94.40
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Just came across this thread where Don Moyer suggests using the small ball valve on my engine, or a c-clamp on the bypass hose, to winterize without removing the thermostat...
"To avoid removing the thermostat housing each year and re-torquing the nuts, many people simply clamp off the by-pass hose with a small "C" clamp. Your aftermarket thermostat has a small bleed hole in the valve which will allow the water/antifreeze in the block and head to pass through slowly." https://www.moyermarineforum.com/for...ead.php?t=1853 Did some more digging and found this, from Don Moyer: "In actual practice, thermostats don't ever seem to completely block off the flow of coolant through the block and head. In the case of OEM thermostats, they simply don't close that tightly, and in the case of our MMI aftermarket thermostat kits (which do close more tightly), the thermostats have a small bleed hole in the movable valve assembly." https://moyermarineforum.com/forums/...ead.php?t=2824 Based on the above, I would think that with a warm engine the thermostat will be partially open, and with the bypass ball valve closed, antifreeze will flow through the engine block, and with the bypass ball valve opened, antifreeze will also flow through the bypass loop. With a cold engine, and the bypass ball valve closed, antifreeze will still flow through the engine block and push through the bleed hole on the thermostat. And obviously with the bypass valve opened, the flow will be almost entirely through the bypass loop. In other words, regardless of whether the engine is cold or warm, it can still be winterized with the process I laid out above without removing the thermostat every season. I think the only state that would not work is if the engine is hot with the thermostat fully open, which would largely prevent antifreeze from flowing through the bypass loop. Last edited by whatjigg; 10-19-2020 at 12:41 PM. |
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TimBSmith (10-19-2020) |
#9
IP: 174.115.32.21
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Thank you! Ok I guess no easy way to git er out. And yes, lots of jiggling necessary haha. Does it need a new gasket every time the T is removed? What’s the permatex for in this case if there’s already a gasket?
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#10
IP: 47.142.133.234
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Quote:
Cut the hoses off the barbs* and scrap them after using them as length cutting guides for the new hose. New hose is flexible and will pop right in. You're probably going to have to do this anyway otherwise the thermostat will not clear. Believe it or not you will save time, effort, and frustration doing it this way. Been there, done this more than once. New gaskets are always advisable. If you stick the gasket to the theromstat housing with permatex the gasket will in theory stick to housing not the head and be easier to remove at the next disassembly. This well will also help in lining up all the holes during reassembly. Is this a real benefit? I don't know. Up to you ex TRUE GRIT *Cut a slit through the hose to the barb rather than across the hose. Last edited by JOHN COOKSON; 10-19-2020 at 08:51 PM. |
#11
IP: 174.115.32.21
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Do I need 1/2” or 5/8” ID hose to replace those two segments?
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#12
IP: 47.142.133.234
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1/2"
ex TRUE GRIT |
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IP: 67.234.48.80
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Be careful when cutting the hose off. I have been to aggressive or just clumsy in a tight space and ended up damaging the fitting. Then the hose will not seal and the fitting has to be replaced. DAMHIK.
Dan S/V Marian Claire |
#14
IP: 174.115.32.21
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Good point, they are brass fittings. I’m thinking I’ll use something like this wire reinforced tubing..
https://www.thechandleryonline.com/p...oducts_id=7330 |
#15
IP: 155.186.122.195
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No wire hose on the cooling!!!
Don't use wire tubing!! If you want to spend money buy the best, blue Goodyear silicone. It's far more pliable and stronger for what you are doing. The wire hose will rust and poke your fingers while looking bad.
Re filling the block and manifold for winterizing, with the t'stat it will just take a bit more time and care to be sure that the block is full bleeding through a small hole in the t'stat (the bleed hole) and without just poor it in. Personally I think splitting and replacing the crossover hose like John suggests would be the easiest. Dave Neptune |
#16
IP: 174.115.32.21
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Oh I don’t think I can get that locally, alternatives?
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#17
IP: 47.142.133.234
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I usually buy four or five feet of hose at a time and keep the unused length on the boat so I'm not chasing after a few inches when ever I need it next. (There will be a next time)
Slit the hose once or twice and gently tease it loose of barb with a screwdriver. Lay off the pliers, as noted. I went to using a bit of pipe thread compound ("pipe dope") on the barb. This makes it easier to remove hose next time and helps make the seal easier with lighter clamp pressure. Hoses will last indefinitely. Excess clamp pressure will ruin them quicker then anything. ex TRUE GRIT Last edited by JOHN COOKSON; 10-20-2020 at 11:43 AM. |
#18
IP: 47.142.133.234
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If you can find it go to an auto parts store and buy some heater hose. Heater hose is rather flimsy and not "marine grade" but will work. I used it for years on my A4 without any problems.
ex TRUE GRIT |
The Following User Says Thank You to JOHN COOKSON For This Useful Post: | ||
Sam (10-23-2020) |
#19
IP: 174.115.32.21
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Thank you for the suggestion, I can probably track some of that down
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#20
IP: 192.186.122.174
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I suggest have a look for Trident 250/100 Series general purpose heater hose at local chandleries. it's what I am using and I find it works well.
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Greg 1975 Alberg 30 |
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