Synthetic oils...

I'm now in the process of switching my entire truck over to Amsoil synthetics and started thinking about the boat. The engine is a given, Amsoil 15W-40 Synthetic Heavy Duty Diesel and Marine Motor Oil however I wanted to know if anyone is running synthetic in there V-drive and transmissions. I'm going to do a little more investigating but these units seem like they would benefit the most from synthetic based oils considering the strain we put on them.

Any input?

Steve

Once you go synthetic you can never go back right?

Steveaz, I changed out my tranny fluid to synthetic around 100 hours (Mobile 1 ATF). It's been an other 100 hours and everything is good.

What I noticed is that the tranny is a bit quiter and smoother.

I'm going to leave the boat with regular oil and just change it every 50 hours. I also have a much larger than stock oil filter. 6 quarts of synth. every 50 hours is a lot of $$$. I'll stick to regular.

I have run only synthetic oil in my Ducati; it's never had an oil related problem, never burned any oil and runs super strong. I have tried a host of different syths in there, Redline seems to be the smoothest. Amsoil made it shift poorly.

I tried switching my old Toyota truck to synthetic oil a few years back. The transfer case, tranny, engien, front and rear cases. The did not like it at all. Switched back to dino oil, but did notice a slight gas mileage improvement running synth every where else.

The benefit of synthetic oil in a v-drive is minimal. The features of synthetic oil that make it attractive for use in the engine (thermal breakdown, ash content, flashpoint, etc) really don't apply to a V-drive. Transmission is another story. Mobil 1 does a good job, it's relatively cheap and widely available. If you're changing V-drive and trans fluid at the end of every season and every 100 hours, you'll be fine no matter what you choose.

As a side note, PCM has stated many times that they do not recommend the use of synthetic oil in their engines. Never got a reason why, but it is still in their newer engine manuals.

(Message edited by csquared on February 05, 2003)

PCM is trying to deter the use for absent minded ppl. If they use regular, they won't follow the thoughts of most, "I use synthetic" so I don't have to change the oil every 50hours, but every 100, cause my car I can go 5000-10,000 miles on, so I must be able to double the intervals on the boat too"

cars and boats are different, we know this, but PCM is just trying to cover warranty and negligence claims against thing like this. It is in the MC manual too.

Yes the two oils are different, but to the engine, it would never know!

KG

Is that right? In a car on regular oil you are looking at 3-5000 miles. With synthetic you are looking at 5-10,000 miles?

so far as I have read. the stipulation to this is that you must change the filter @ 5k, to still get the full use of the oil.

An engineer told me one time, you could start a car and drive it across the county 10 times with the same oil. The parameters were:
- you had to move at highway speed and almost never stop, except for the regulars, gas food and tolls.

I sort believe him as I drive alot by most standards. I change the oil in my car every 7k (synthetic) and it is always clean, nearly as clean as when it went in new. I drive nearly 400 miles a week on the highway, with barely any stop n go city driving except around town which is minimal. It was a litte bit different with the regular oil, but you could still see thru it too!

KG

I run synthetic in my toyota

BMW and the new Mini Coopers come with syn in them. The first service is at 10,000 miles. I think the second is at 25,000 miles (I'll have to check my manual). The oil changes are free (for the Mini anyway) for the length of the warranty, which is bumper to bumper, including the brake shoes, so you'd think they would want to change the oil a little more often.

My other cars get it changed every 3,000 miles. The boat every 50 hrs.

Synthetic is required in Toyota boats. The stock oil is conventional, at the first oil change you're supposed to switch to synthetic. That's at 200 hours. The rings won't seat properly if you use synthetic in a new engine, you'll get blow by and your oil will get dirty fast. New car manufacturers break the rings in somehow to run synthetic from day 1. I have had problems with synthetics in high mileage/older engines, it is so slick that it gets past seals and leaks develop. Going back to conventional oil fixed the problem.

Ty, my understanding is that is correct.

Sean, agreed, I've run synthetic in my R1 since it had 3K on it and it always looks great...no shifting problems and change every 2K.

As far as my truck, there is a lot of data out there and I'm pretty comfortable with that. Rear diff is synthetic from the factory. Engine oil changes can be extended to 15K (diesel) but will do oil analysis after 5 and 10. Haven't completely decided on how I'm going to proceed with the boat, will probably do analysis and see how it is after 50 hours.

Shawn, appreciate the input. You don't think the decrease in resistance due to the properties of synthetic would be less strain on the V-drive unit? If so, why does GM spec it in their rear diffs on heavy duty trucks?

As far as cars and boats being different...true, however a boat typically runs at a lower temp so thermal breakdown isn't much of an issue but soot levels are.

Psyclone, I'm assuming you meant 20hours. My boat has almost 200 hours and has had the 4 engine oil changes and 2 transmission/V-drive oil changes.

Steve

Break in period is 15 hours, service interval is 200 hours. You are supposed to keep conventional oil in it for the first 200 hours. I usually change during the middle of the season and at the end, I put 170 hrs on last year. The oil is still clean after 100 hours. Trans oil every 100 hours. Spark plugs and timing belt every 1000 hours or ten years.

so what is ther verdict?
most people use syn in their engine?
most people use syn in their tranny?
most people use syn in their v-drive?

Check into using diesel rated 15w-40 oil as they are under stringent guidelines due to the demands placed upon it buy diesel engines and diesel fuel. I've heard from people in the petroleum industry that synthetics are a wom.

I've run both and to be honest can't find any distinguishing differences to justify spending more. I've had 285,000 on a buick v-6, and 200,000 on a chevy v-6 both on nothing but conventional oils they are both still running although I no longer own them.

Steve,

Isn't the synthetic gear oil that is spec'd in the rear differentials a 75W-140 weight (or something like that)??
IMO, their are two considerations: the advantages of synthetic oil are cold temperature pumpability, higher burn-off temperature and higher tolerance to viscosity breakdown. Since there are no by-products of combustion in the V-drive and temps are relatively low, the benefits of synthetic oil will not be fully realized. Secondly, and most importantly, is the use of a multi-weight oil in the V-drive. A 5W-30 synthetic oil and a 30W-30 oil are very different. A 5W-30 oil flows easier when cold and then thins out to the same viscosity as a 30W oil as it get hot. The multi-viscosity oil may be a little thin for the V-drive. You probably won't hurt anything and since it only holds about a quart, the financial increase isn't significant. Give it a try and if it gets noisy, switch back to regular oil. All the newer PCM/Walter V-drives are using ATF instead of motor oil and Walter recommends motor oil instead of ATF if the V-drive is noisy.

Ty, I use (in a 1999 GT-40 motor):
engine: 40W-40 in the summer, 30W-30 in the winter. All non-syntheitc. Changed every 50 hours or two months.
tranny: Mobil 1 syn ATF changed every season or 100 hours.
v-drive: 30W-30 changed at the end of every season.
Plugs and impeller changed, cap, rotor and timing inspected in the spring, belts and hoses replaced as needed.