Can i use it?

Oct 22, 2006
35
O DAY 27 LE philadelphia pa
I have a 1987 westerbeke 10-2 diesel. Oils specs. API 10W 30 CC or better. I have Shell ROTELLA T5 SYNTHETIC BLEND
10W - 30 DIESEL. Can i use this oil To add to existing oil or a total oil change?
 
Aug 12, 2020
53
Lancer 36 Pago Pago
The Shell has an API of CK4, which exceeds CC i think, but the issue of mixing synthetic and dinosaur juice is not well regarded....use one or the other. Some people do not favor using synthetic oil in older engines; I am not too preferential myself. You may want to research the issue further.
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
Replace the oil to avoid mixing different oil specs............besides your engine oil capacity is only 2 quarts. Quick and easy to do with a oil extractor inserted into the dip stick down to the bottom of the oil pan. Suggest changing out the filter part no. 36918 at the same time.

Link to manual: https://www.westerbeke.com/operator's manual/33105_10-2-3.0_operator.pdf
Engine parts list: https://www.westerbeke.com/parts manual/33404_10-2-3.0_parts_list.pdf
Westerbeke oil filter:
 

Johnb

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Jan 22, 2008
1,420
Hunter 37-cutter Richmond CA
The first time ever I did mine I did a double oil change with about a 10 minute run in between. Changed the oil filter with the second oil change. Probably overkill, but think of what a re-power costs.

Also double changed the transmission fluid, and the cooling water, except I just used plain water for the first change!
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
The first time ever I did mine I did a double oil change..................Also double changed the transmission fluid, and the cooling water...................
Interesting approach,...........I have always changed once and inspected the fluids after the fluid change and running the engine to confirm they were not contaminated. If they were, then I would change a second time.
 
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Johnb

.
Jan 22, 2008
1,420
Hunter 37-cutter Richmond CA
I should have said, it was because I did not know what was in there.
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
Thought that was the case........especially on your new to you sailboat.
 
May 24, 2004
7,129
CC 30 South Florida
The issue with synthetic oils vs conventional is that a good number of people have reported their older engines developing oil leaks after switching to synthetics . This is not very scientific data but the numbers point to something. The second reason tends to give the first reason the benefit of the doubt. Synthetic oils are at their best in clean enclosed equipment like a transmission where they can practically last forever, but in combustion engines where where oil contamination with combustion by-products is inevitable it tends to negate the long longevity benefits of the oil. The final premise is that if the oil is going to get dirty and I may have to change it as regular as conventional oil why pay more and also run the apparent risk of developing oil leaks. No I would not mix one with the other.
 
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srimes

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Jun 9, 2020
211
Macgregor 26D Brookings
I have a 1987 westerbeke 10-2 diesel. Oils specs. API 10W 30 CC or better. I have Shell ROTELLA T5 SYNTHETIC BLEND
10W - 30 DIESEL. Can i use this oil To add to existing oil or a total oil change?
Yes. Safe either way.

Synthetic oil is better in every way except price and leaks. It pours out of the jug quicker and if you have a bad gasket/seal it'll leak out of that more quickly too. If it makes a mess you may want to switch back.
 
May 24, 2004
7,129
CC 30 South Florida
The first time ever I did mine I did a double oil change with about a 10 minute run in between. Changed the oil filter with the second oil change. Probably overkill, but think of what a re-power costs.
That might be a bit of an overkill. We change oil to restore the loss of viscosity and to remove contaminants not removed by the filter. It is likely that old black oil we have been running for the past hours is still adequately good and even if we are only able to restore and remove 95% of the old oil the new oil will negate for many hours to come any ill effects of that 5% we did not get at. I use a vacuum pump with tubing inserted down to the bottom of the crankcase and remove the total contents of the old oil retained inside the oil filter.
 
Mar 20, 2016
594
Beneteau 351 WYC Whitby
Synthetic oil is high in detergents . Putting it in an older engine cleans gunk build up around sealing surfaces (seals) and presto ,you have major leaks after a short time . Also older engines used buna or nitrile seals ,new engines use viton oil seals which can tolerate different chemicals used in newer oil mixes