Like Stu indicates it sounds like a myth to me. Follow engine's manufacturer guidelines and if there are none then that is the answer.
Why change oil twice?
- Thread starter Biobob Catalina 27
- Start date
I follow the Yanmar guidelines for my 3GM30F -1235, change at 100 hours and my Northern Lights 5kw generator at just under 3,000 hours, change at 200 hours. I used to do it seasonally when I would winterize for three months. I'm not a mechanic, and I won't go much beyond these numbers, but I really don't see why a boat Diesel engine is any different than a car or truck. You don't change the oil every month in your car or truck and I wonder why these low hours are necessary. Not recommending anyone go more, but why so short a time?
Re: changing oil twice.
Here a link to an article on the subject by Don Casey.
As some have said...oil is cheap, engines are not.
http://www.boatus.com/boattech/casey/changing-oil.asp
Here a link to an article on the subject by Don Casey.
As some have said...oil is cheap, engines are not.
http://www.boatus.com/boattech/casey/changing-oil.asp
I've yet to see any credible data that suggests changing brand new oil is worth doing.
That said I change my oil twice in the fall, before layup, to get it perfectly clean.. Warm up, drain oil, change filter & oil, run, change oil again but not filter, run, check cleanliness of oil, seal engine intake, seal exhaust outlet, put to bed...
In the spring crank it over, with fuel shut off pulled, a few times, before actually starting it.. I do not change perfectly clean & unused oil in the spring...
That said I change my oil twice in the fall, before layup, to get it perfectly clean.. Warm up, drain oil, change filter & oil, run, change oil again but not filter, run, check cleanliness of oil, seal engine intake, seal exhaust outlet, put to bed...
In the spring crank it over, with fuel shut off pulled, a few times, before actually starting it.. I do not change perfectly clean & unused oil in the spring...
I put less than 100 hours a year on my engine and only change my oil at the beginning of season in Spring. I know the reason people give about not letting the 100 hour oil sit in the sump all winter, and that oil changed in the Fall and sitting all winter has moisture in it. But I tested the old oil at the start of the spring once and it was good far as pH, sediment, and water so think the double change falls into the useless things people do because it makes them feel good more than any impact on the engine.
I think before some people tried to understand why I heard people changed their oil in the spring was because they forgot to or didn't do it in the fall. At that time I asked a mechanic, 'what difference does it make?" He said they like to change the oil in the fall before winter storage so it doesn't have old oil just sitting in there for months gunning things up 
In a word it's overkill. I'm a fanatic about clean oil but
by the same token there is a practical limit to that. There is a situation of condensation but that alone is not enough to warrant another change. I would think that your money would be better spent working that change into your maintenance schedule during your operational season. Tell you what though, you sure can't go wrong any time that you change it and those in favor of the 2 changes would be erring on the side of caution.
by the same token there is a practical limit to that. There is a situation of condensation but that alone is not enough to warrant another change. I would think that your money would be better spent working that change into your maintenance schedule during your operational season. Tell you what though, you sure can't go wrong any time that you change it and those in favor of the 2 changes would be erring on the side of caution.
It's just a plot to sell more oil. Is there ANY data to support changing in the Spring if it was changed in the Fall? Oil should be changed in the Fall so any crap isn't sitting there all Winter. If you are worried about it you can send your oil to Blackstone Labs
http://www.blackstone-labs.com/
for oil analysis.
In God we trust. All others bring data.
http://www.blackstone-labs.com/
for oil analysis.
In God we trust. All others bring data.
There is no reason to change the oil if it hasn't been used. The rationale behind a double change is that frequently the oil drain is not located at the low point in the motor, and by changing twice you can get more clean oil in the system. Of course you can use a dipstick oil change pump that is fed to the back of the pan too. Unless you used a heavy grade preservation oil, changing oil in the spring is not worth the 20 bucks of oil except to make the owner feel good.
On the other hand, the rationale behind keeping a gas tank full to prevent condensation is sound science. Less air in the tank means less water (humidity) available for the ethanol to bind with. If you drain your tank completely, and fog your carb, you are also reducing the chance of ethanol binding with too much water and falling out of solution (phase separation.)
Anything else is smoke screens and snake oil. Save your money and time, and just go sailing in the winter. I change my oil in September after a summer of fun (and a long trip or two.) I change it again in May after sailing in the winter and to get ready for my next summer adventure.
Just my 2 cents worth.
Dan
On the other hand, the rationale behind keeping a gas tank full to prevent condensation is sound science. Less air in the tank means less water (humidity) available for the ethanol to bind with. If you drain your tank completely, and fog your carb, you are also reducing the chance of ethanol binding with too much water and falling out of solution (phase separation.)
Anything else is smoke screens and snake oil. Save your money and time, and just go sailing in the winter. I change my oil in September after a summer of fun (and a long trip or two.) I change it again in May after sailing in the winter and to get ready for my next summer adventure.
Just my 2 cents worth.
Dan
Thanks all for the input and knowledge, and Dan, wish I could have winter sailing, the Chesapeake froze over mostly this winter and I was on the hard.
If the boat had sat unused for a few years, I'd change the oil first thing. Other than that, I only change in the fall. Even here in Michigan, I doubt there would be enough condensation over one winter to do any harm, and that would boil off on the first good running. I've only changed in the spring when I've bought a used boat and didn't know for sure when it was last done.
Here's a better question..
How many actually follow the manufacturers instructions for winterizing their engines?
Here are a few I bet many owners choose to ignore:
Westerbeke / Universal:
"Lubrication System
With the engine warm, drain ALL the lubricating oil from the oil sump. Remove and replace the oil filter; place some paper towels and a plastic bag around the filter to catch the oil while removing it.
When installing the new oil filter, be sure to apply a small amount of oil on the sealing "O" ring at the base of the filter. Fill the sump with the correct amount of oil for your engine model (Ref: Operator's Manual or Technical Manual). Use an oil with an A.P.I. Spec. CC. Run the engine and check for proper oil pressure and insure that there are no leaks.
Do not leave old engine lubricating oil in the sump over the winter lay-up period. Lubricating oil and combustion deposits combine to produce harmful chemicals which can reduce the life of internal engine parts.
Transmission
Drain the lubricant from your transmission and/or V-Drive. Refill with the proper lubricant to the full mark on the transmission dipstick. Run the engine and shift the transmission into forward and reverse one/two times. Stop the engine and check the transmission oil level; add lubricant as needed. Check for leaks.
Fuel System
Top off your fuel tanks with #2 diesel fuel. Fuel additives should be added at this time to control algae and condition the fuel. Care should be taken that additives used are compatible with primary filter/separator used in the system. Change the element in your primary fuel filter/separator if it contains one, and/or clean the separator sediment bowl.
Change the fuel filter elements on the engine and bleed the fuel system, as needed. Start the engine and allow it to run for 5 - 10 minutes to insure that no air is left in the fuel system and check for any leaks that may have been created in the fuel system during this servicing, and correct as needed.
Intake Manifold
With a clean cloth lightly soaked in oil, place it in the opening of the intake manifold so as to block it closed. DO NOT shove the cloth out of sight into the intake manifold. If you cannot see it next Spring, and you attempt to start your engine, you may need the assistance of a servicing dealer. Take a note to remove this cloth prior to start-up. The exhaust through hull can be closed in this same manner.
Sea Water Circuit
Close the thru hull seacock. Remove the raw water intake hose from the sea cock. Place the end of this hose into a 5-gallon bucket of clean fresh water. Before starting the engine, check the zinc pencil found in the primary heat exchanger on the engine and clean or replace it, if required. Clean your sea strainer, if one is installed in the inside of the hull.
Start the engine and allow the raw water pump to draw the fresh water through the system. When the bucket empties, stop the engine and refill the bucket with an antifreeze solution slightly stronger than needed for winter freeze protection in your area.
Start the engine and allow all of this mixture to be drawn through the raw water system. Once the bucket empties, stop the engine. This anti-freeze mixture should protect your raw water circuit from freezing during winter lay-up, as well as providing corrosion protection.
Remove the impeller from your raw water pump (some antifreeze mixture will accompany it, so catch it in a bucket). Examine the impeller. Acquire a replacement if needed and a cover gasket. Do not replace the impeller back into the pump until the Spring commissioning.
Propeller Shaft Coupling
Disconnect the propeller shaft coupling from the transmission. (If the boat remains in the water during winter storage, this need not be done).
This is a good time to check the security of the coupling to the propeller shaft. Insure also that the coupling set screws are tight and wired so as not to loosen. The engine alignment to the propeller shaft should be checked in the Spring when the boat is placed back in the water, and the mast stepped, and the rigging tuned.
Fresh Water Cooling System
The use of a 50-50 solution of antifreeze and fresh water is recommended for use in the fresh water cooling system year round. This solution may require a higher concentration of antifreeze, depending on the area's winter climate. This solution should be checked to insure proper freeze protection.
Should more antifreeze be needed, drain an appropriate amount from the engine block and add a more concentrated mixture. Operate the engine to insure complete circulation throughout the system. Recheck."
How many actually follow the manufacturers instructions for winterizing their engines?
Here are a few I bet many owners choose to ignore:
Westerbeke / Universal:
"Lubrication System
With the engine warm, drain ALL the lubricating oil from the oil sump. Remove and replace the oil filter; place some paper towels and a plastic bag around the filter to catch the oil while removing it.
When installing the new oil filter, be sure to apply a small amount of oil on the sealing "O" ring at the base of the filter. Fill the sump with the correct amount of oil for your engine model (Ref: Operator's Manual or Technical Manual). Use an oil with an A.P.I. Spec. CC. Run the engine and check for proper oil pressure and insure that there are no leaks.
Do not leave old engine lubricating oil in the sump over the winter lay-up period. Lubricating oil and combustion deposits combine to produce harmful chemicals which can reduce the life of internal engine parts.
Transmission
Drain the lubricant from your transmission and/or V-Drive. Refill with the proper lubricant to the full mark on the transmission dipstick. Run the engine and shift the transmission into forward and reverse one/two times. Stop the engine and check the transmission oil level; add lubricant as needed. Check for leaks.
Fuel System
Top off your fuel tanks with #2 diesel fuel. Fuel additives should be added at this time to control algae and condition the fuel. Care should be taken that additives used are compatible with primary filter/separator used in the system. Change the element in your primary fuel filter/separator if it contains one, and/or clean the separator sediment bowl.
Change the fuel filter elements on the engine and bleed the fuel system, as needed. Start the engine and allow it to run for 5 - 10 minutes to insure that no air is left in the fuel system and check for any leaks that may have been created in the fuel system during this servicing, and correct as needed.
Intake Manifold
With a clean cloth lightly soaked in oil, place it in the opening of the intake manifold so as to block it closed. DO NOT shove the cloth out of sight into the intake manifold. If you cannot see it next Spring, and you attempt to start your engine, you may need the assistance of a servicing dealer. Take a note to remove this cloth prior to start-up. The exhaust through hull can be closed in this same manner.
Sea Water Circuit
Close the thru hull seacock. Remove the raw water intake hose from the sea cock. Place the end of this hose into a 5-gallon bucket of clean fresh water. Before starting the engine, check the zinc pencil found in the primary heat exchanger on the engine and clean or replace it, if required. Clean your sea strainer, if one is installed in the inside of the hull.
Start the engine and allow the raw water pump to draw the fresh water through the system. When the bucket empties, stop the engine and refill the bucket with an antifreeze solution slightly stronger than needed for winter freeze protection in your area.
Start the engine and allow all of this mixture to be drawn through the raw water system. Once the bucket empties, stop the engine. This anti-freeze mixture should protect your raw water circuit from freezing during winter lay-up, as well as providing corrosion protection.
Remove the impeller from your raw water pump (some antifreeze mixture will accompany it, so catch it in a bucket). Examine the impeller. Acquire a replacement if needed and a cover gasket. Do not replace the impeller back into the pump until the Spring commissioning.
Propeller Shaft Coupling
Disconnect the propeller shaft coupling from the transmission. (If the boat remains in the water during winter storage, this need not be done).
This is a good time to check the security of the coupling to the propeller shaft. Insure also that the coupling set screws are tight and wired so as not to loosen. The engine alignment to the propeller shaft should be checked in the Spring when the boat is placed back in the water, and the mast stepped, and the rigging tuned.
Fresh Water Cooling System
The use of a 50-50 solution of antifreeze and fresh water is recommended for use in the fresh water cooling system year round. This solution may require a higher concentration of antifreeze, depending on the area's winter climate. This solution should be checked to insure proper freeze protection.
Should more antifreeze be needed, drain an appropriate amount from the engine block and add a more concentrated mixture. Operate the engine to insure complete circulation throughout the system. Recheck."
I always follow manufactures recommendations. I will readily admit I'm a manual reader and read every manual for everything I've ever owned cover to cover before I turn anything on. Each winter I bring all the manuals for everything on the boat home and reread them over the course of the winter. Maybe it is a little compulsive but what can I say