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View Full Version : Necessary to change oil?


CruisinGA
10-27-2010, 10:29 PM
Got about 15 hrs of runtime on most recent change of Rotella T 15w-40.

I know that part of the reason for changing oil at winterization is so that corrosive combustion related impurities don't sit in the oil throughout the engine all winter. However, with 15 hrs at most on the last engine oil change, would you bother to change again at winterization?

I know this is a judgement call, but some additional perspectives would be helpful.

Thanks,
Bailey

Gamble
10-27-2010, 11:19 PM
had the same issue a year ago and asked the dealer........they said leave it and run it another year.

Willski
10-27-2010, 11:29 PM
same here. 15 to 20 hours on my oil. I drained the water out a few weeks ago, because I've been gone, and didn't want to have that mistake! I am anxious to see what people think. It really doesn't cost much to do an oil change, but I like to do it when the engine is warm, and now that I drained the water out, I don't want to refill and run it.

thatsmrmastercraft
10-27-2010, 11:50 PM
A person could warm the oil without running the engine by applying a magnetic engine heater to the side of the oil pan for a little while, then proceeding with the oil change.

JLeuck64
10-28-2010, 12:21 AM
Got about 10 hours into an oil change last year before the end of the season... left it in there over the winter.

Workin' 4 Toys
10-28-2010, 12:26 AM
I would change it.

Chicago190
10-28-2010, 12:43 AM
same here. 15 to 20 hours on my oil. I drained the water out a few weeks ago, because I've been gone, and didn't want to have that mistake! I am anxious to see what people think. It really doesn't cost much to do an oil change, but I like to do it when the engine is warm, and now that I drained the water out, I don't want to refill and run it.

If the boat is already winterized just drain the oil from the hose overnight into a drain pan.

Bouyhead
10-28-2010, 06:28 AM
I would change it. Think of all the sleepless nights you won't have to contend with.

Craig
10-28-2010, 08:16 AM
I had about 10 hours on an oil change at the end of the year last year. I left it over the winter, ran it another 15 or so this spring and then changed it.

I had about 40 hours on an oil change this year, went ahead and changed it.

I have a hard time believing that oil develops corrosive properties being used how it is designed to be used. If anyone has anything besides anecdotal evidence that would convince me otherwise I would be very interested.

All of the thermal cycles of the winter probably have a detrimental impact on the viscosity and surface tension of the oil. How quickly these changes happen I don't know but would be interested in learning.

Jerseydave
10-28-2010, 11:38 PM
For the cost I would change it. My buddy has an alcohol dragster and he changes it after every run (15 minutes at the most on the oil) But that's apples and oranges since your boat's engine doesn't get punished that hard.

Plus you will be able to run it 50 hours next year instead of just 35! :D

JohnE
10-29-2010, 10:21 AM
I had the same question last year. I asked my dealer he said don't bother changing it. I had no problem sleeping all winter.

CruisinGA
11-23-2010, 09:28 PM
FWIW- I didn't change it. I've got my oil change interval even now and don't want to lose it :D .

Did some more thinking on the topic though- the primary reason cited for changing oil at winterization regardless of hours is because the old oil has corrosive combustion byproducts, this fact I don't disput. However, changing oil at winterization and then not running the engine afterwards doesn't do any good because- all the oil coating engine parts aside from the oil pan and a passage or two is still the old oil, unless the engine is run for a short period of time with the new oil, which many people don't do.

JohnE
11-23-2010, 10:51 PM
FWIW- I didn't change it. I've got my oil change interval even now and don't want to lose it :D .

Did some more thinking on the topic though- the primary reason cited for changing oil at winterization regardless of hours is because the old oil has corrosive combustion byproducts, this fact I don't disput. However, changing oil at winterization and then not running the engine afterwards doesn't do any good because- all the oil coating engine parts aside from the oil pan and a passage or two is still the old oil, unless the engine is run for a short period of time with the new oil, which many people don't do.

I was due this year so I changed the oil at the day I winterized. Ran it to get good and warm to change the oil. Changed the oil then let it get good and warm again before winterizing to get the tstat to open so I could drain then fill w/ antifreeze.

I think the entire notion that anything the least bit detrimental will happen by leaving 15 hour old oil in the engine for 5 or 6 months. Yes, in theory blah blah blah..

Kyle
11-24-2010, 01:07 AM
I would say that you will be okay without changing. Would you change the oil in your tractor, lawn mower, or classic car with 15 hours or 1,000 miles on the last change? I would not. You will be okay. Don't waste your money.

FWIW my grandad has a classic car. We may drive it 3000 miles total a year. About every 4 months or so we drive the car. We change the oil once a year. Been in the crankcase last year for the first time and everything was ok. It's a 1960 Austin 3000. Very rare and it's in very good shape.

HDAVIS
11-24-2010, 10:19 PM
I always change my oil every 50hrs or once a year. I would not let my oil stay in my engine over a year. Also, I change my oil in the spring. This is what my dealer recommends and I am very "picky" with my MC190.

CruisinGA
11-25-2010, 01:26 AM
I change every 50 hrs as well. For me, that is 3 times a year. Just couldn't justify the time and hassle of changing 15 hr old oil. I'm glad y'all agree. :D

JohnE
11-25-2010, 03:00 AM
I always change my oil every 50hrs or once a year. I would not let my oil stay in my engine over a year. Also, I change my oil in the spring. This is what my dealer recommends and I am very "picky" with my MC190.

so you don't put at least 50 hours a year on? I'll guarantee that if you let your 20 or 30 or 40 hour oil stay in your boat for a year that you will be none the worse for wear.

Gravy
12-11-2010, 11:38 PM
change it after you run it once or twice in the spring....think green!

Thrall
09-15-2011, 09:42 PM
I'll still change out my engine and trans oil, even though I only got about 25hrs on the boat this year!:(
Thinking about saving it though and using it in the truck or mowers, etc. Seems a shame to waste perfectly good oil, but the MCX is the best looking engine I own, it gets special attention!
Agreed, it won't hurt the engine to leave it in. Heck my old Jeep had 10-20 year old oil in it when I bought and I ran it for several years (not often though) before changing it and it still runs fine.
I had an old Blazer that I never changed the oil in. Ran the cr@p out f it snowplowing and highway driving. Gave it a new filter or 2, but it burned/leaked enough oil, I figured by default I was always gradually changing the oil!

yippikaiyay
09-16-2011, 09:46 AM
I've thought about this issue as well, I'm usually around 70 hours per season, so once I hit around the 35 to 40 hour mark, I change the oil. Allowing me to get 30 to 35 hours with that service, before changing again for winterization.

Kevin 89MC
09-21-2011, 06:38 PM
I rarely get to 50 hours in a season, but I change mine every fall at winterization anyways. That's the way the head MC dealer mechanic told me to do it, figure he knew best. I figure I'd rather have fresh oil in it all winter, than oil that has all kinds of junk in it sitting all winter. Every fall it is still pretty clean, but I don't feel like letting it go over the winter. Our harsh winters don't help either, we usually get a cold snap or 2 down to 15-20 below zero.

I did find it interesting that when I blew my head gasket this summer, I changed the oil & filter right after that, and it came out pretty black. I did run the engine for a few times after the HG blew (thinking it was an exhaust leak), so I was essentially running it very rich. I have only put on about 10-15 hours since the new HG & GT40 valves, but I will for sure be changing it this fall, I always figure better to be safe than sorry, or worry about it over the winter.
Kevin

HDAVIS
09-21-2011, 09:01 PM
I have a 1996 PS190. The head mechanic at the MC dealership said change every 50 hrs. But, I never leave oil in more than a year. I change my oil in the spring. I have never had a problem.