Trojan Boat Forum

I am running a couple of 8.2 L, Mercruiser Bluewater inboards in my (new to me), Trojan 370 Express.

I count myself fortunate to have received from the former owner, most of the applicable records and manuals, including the General Use Manual for these engines.

In the manual, when the average air temperature is above 50 degrees F, the oil they recommend using is: straight weight, Quicksilver 4 cycle marine engine oil. The suggested grade is SAE 40W SG or CD.

Failing the availability of this oil, they recommend replacing the Quicksilver with a multi-viscosity 20W-40 (SG/CD 11) or as a second, but less preferable choice, 20W-50 (SG/CD 11)

Well, it has become a tough process for me to actually get my hands on this particular brand and grade of oil. The closest I've come is 20-50 engine oil.

Based on the fact that this particular Mercruiser engine manual was printed in 1993, my question is does anyone here have any thoughts that they can share, when examining the above mentioned choice of engine oil for these power plants? Is it possible that the oils of that era m have been super-seeded by a more available brand/grade?

Secondly, the rocker covers on each of these engines comes with it's own oil filler cap. In other words, two oil filler caps per engine. One cap is designated in yellow while the other has been left unmarked. I almost fainted when, after dumping in a quart of oil, I glanced across the top of the engine and noticed the designated oil filler carp on the other side. I assume this feature was added to allow someone to add a quart to either engine from the space between the engines without having to actually reach across the top of either engine.

Any thoughts on another engine oil.

Thanks

Rick

You can get Mercruiser/Quicksilver 25W40 at Walmart and Amazon among other places. I would not worry so much about the first number as it is the cold viscosity and only matters at startup.

I run Shell Rotella T 15W40 in my boat as it is a fairly high quality oil at a reasonable price.

25w-40 merc oil will be fine .But I would use Shell Rotella 15W40 my self . Crusader that use the same base engine recommend it (15w-40) I used it in my last 5 boats and its my oil of choice when servicing other boats . Straight 40w is old school . The only thing I would use straight 40w on is 2 cycle Detroit Diesels .

Use the oil cap that's easier to get to .

An oil discussion could go on for days, but most of the guys I know run Shell Rotella. I like Amsoil Z Rod 20W50. Its expensive, but it has a high zinc content, and anti rust additives for long winter lay-ups that a typical hot rod (or in this case boat) would have in cold NY. You can order it online. They also have 10W30 in the same format.

Okay, guys. Thanks very much.

This is exactly the info I needed.

If I run into an issue (I'm in Canada) with the Shell Rotella or failing that, the Amsoim Z Rod 20-50 - I'll let you know. I'll try Walmart today. But I know that our local Canadian Tire stores don't stock either.

Another question I have is that I assume they don't make synthetic oils in this grade.

Thanks,

Rick

You really only need to be worried about the upper number and being from the Great White North, I would stick with a 30 or 40.

Shell T6 makes a 5W-40 and if you want a full synthetic, this will suit you nice. I'm sure you have Mobile 1 and if you want a solid synthetic, you can find a 15W-40.

Thanks, bjanakos.

Yeah, I'm going to go down to Walmart as recommended by WayWeGo and check (but doubtful that Canadian stores stock Quicksilver products.

I use Mobil 1 in my cars.

Engine manual suggests 50 with 40 as second choice. Up here, I haven't been able to find a 50 that has a lower number than 30 and engine manual states 20 - 50.

Going over to Princess Auto right after I visit Walmart, just in case they're stocking these brands. Fingers crossed.

Will let you guys know if there's a Canadian version for these grades.

Failing all of the above, I'll just find and use Mobil 1 (15-40) because I like Synthetic.

Rick

After 17 years and 140K heavy towing miles on my F350, I switched from Rotella T to the synthetic Rotella T6 5W40 the bjanakos mentioned. My reason for doing so is that this is a turbo charged engine that I have modded to run higher boost and I wanted the additional protection of the synthetic. The oil change came at the same time I did a partial rebuild of the turbo and high pressure oil system among other things.

Rotella T and T6 are fairly high ZDDP oils, which is a good thing for our older engines. They are commonly used in tractor trailer diesel engines, so you should not have any problems finding them. Mobil Delvac and Chevron Delo are also popular diesel oils that have slightly higher ZDDP levels. For that matter, you are pretty safe running any diesel rated oil, as they almost always have high ZDDP levels. If you really want to have a Mobile synthetic oil, look at Mobil Delvac 1.

My personal choice is to run Rotella T in the Trojan because I think it is an excellent oil at a good price.

Ah, I love a good oil thread!

Just for the heck of it to keep oil thread going I use Dello 14w40. LOL

Hi,

Well after running around a bit today, I managed to find a supply of Shell Rotella 15W40.

It was only available in 5 litre containers (in the U.S. this would be a 5 quart container)

I bought four jugs this time around. But before the summer is over I'll go back and pick up five more, then insist my marina uses it for my winterizing oil change.

I like my oil in 1 qt containers, for ease of storage and also ease of pouring into a funnel. I'm going to transfer these jugs of Rotella into empty 1 qt containers (pain in the ass but I have no choice.)

So all in all, a very good day. Thanks for the advice.

Another problem solved.

Rick