What about 5w-40 diesel engine oils?

[twb]

Does anyone have any experience with or opinions about using high end 5w-40 diesel oils in marine engines? I'm mostly concerned with recreational boats. I had been thinking about starting a thread specifically about Delvac 1, but now that my favorite oil manufacturer (Schaeffer Mfg) has come out with a 5w-40, I figured I'd open it up. Let's include synthetic Rotella, and any others I don't know about.

I know some in the boating forum won't use anything but straight 30 or 40 weight oil. Your flames, err, I mean opinions, are welcome too!

 

[cryptokid]

well i for one would like to dispell a common myths about marine engines. people awalys talk about water in the oil when talking about marine engines. why is this?

if youre bost engine is functioning properly it shouldnt have ANY water comtamination issues at all. most if not all boat engines are covered behind some sort of cowling to protect them from rain.

most marine engines also have thermostats and get a constant supply of cool fresh water. usually their thermostats are of a lower tempature, such as 160 or 160f, i dont know why this is but a 180F engine is still hot enough to evaporate ANY water in the oil. think about this, water evaporates at room tempature. its certainly gling to evaporate when its inside a 180F sump with positive crankcase ventilation constantly exchanging the air inside the sump and block.

what i am basically trying to sasy is that the typical "marine" enviroment is NOT any worse than being in the endine bay of a truck or car.

now as to typical marine cruising rpm's, thats another story. rcruising at 4000 or 5000 rpm's certainly isnt a good way to make an engine last. but thats why you should use a good quality shear resistant oil.

but dont for a second think that a boat engine is under a harsher enviroment than a car or truck engine.

 

[Drstressor]

If a boat is stored in the water, the engine is exposed to multiple cycles of heating and cooling in an atmosphere that often exceeds 100% humidity. Thus, condensation on metal parts, particularly in the valve train area, is a real consideration. The net result is not so much water accumulation in the oil, but increased corrosion of the metal parts during storage. This results in accelerated corrosive-abrasive wear upon startup. An oil with a strong TBN such as a HDEO gives better protection, since this type of corrosion is related to acids formed on the metal surfaces as the result of oxidation of combustion products.

Diesel oils are typically quite shear resistant and also resist foaming and oxidation at high engine operating temperatures (which have more to do with load and rpm than the temperature of the coolant). So in general, HDEOs are a good choice for marine applications. Note that 4-stroke Mercruiser oil carries a diesel certification. Thus, they are likely using a diesel additive package that provides that certification.

 

[cryptokid]

most automobile engines also see 100% humidity for a couple hours every single night. think about every night when the dew comes outside and forms all over the engine bay.
same thing as a boat sitting in the water.

see what i am saying. there isnt much variation in operating conditions.

 

[rugerman1]

OFF TOPIC(sort of):
To what degree do you think a Wolverine Pan Heater might help?
From the Wolverine website FAQ:

quote:

---

REDUCES water and acid accumulation in the oil supply

---

IN AN AUOTMOBILE APPLICATION:If a pan heater keeps an oil warm,and the oil is never subjected to condensation inside the pan,does this sound like a good scenario?
Do you think that the TBN will be more stable?Does less internal condensation lead to less iron in UOA's?

 

[Drstressor]

A marine engine siting below deck is subjected to nearly 100% humidity almost all the time. But the major difference is that boat engines typically sit for long periods of time without running, whereas automotive engines rarely sit for more than a few days at a time without being run. So the thin coating of oil on the metal parts doesn't have much time to drain off and oxidize before the next duty cycle.

In theory, a heater that maintains a fairly stable temperature should reduce condensation and minimize exposure of the oil to water. But the type of condensation that occurs within an engine is not the same what you see on the hood of a car in the morning. That's a product of radiational cooling and precipitation of water vapor. Acid formation in oil surface films would be more of a function of relative humidity rather than actual condensation of visible water droplets. While water is not miscible with oil, a small amount of water can diffuse into oil at a rate depending on the vapor pressure (i.e. the relative humidity).

 

[twb]

Geez crypto, you hijacked my thread off topic on the very first follow up!

I'm not sure I've seen/heard anyone talk about water in their engine oil. It's a constant topic when talking about lower units on outboards and sterndrives though.

I agree fully that some people get carried away with thinking the demands of a marine engine are so different than auto engines. There is a difference, just not as extreme as some seem to believe.

I expected this thread to get fixated on whether the 5W part is too thin, or the viscosity index is too great. Y'know, the wailing and gnashing of teeth that it will shear down to the equivalent of urine in their big, bad marine engine.

Myself, I've always used Schaeffer's 15w-40 in my boat. But I had been considering trying Delvac 1 (or the supposed Delvac 1 relabled as truck & SUV). Now that Schaeffer has come out with a 5w-40 diesel, I just can't wait to get my boat out of storage and change the oil! I also can't wait to get it in my VW 1.8T despite the phenomenal UOA that Schaeffer 5w-30 has given me in that engine.

 

[1 FMF]

the straight 30 or 40 oil is definitely not a good idea when running a boat in colder weather. Castrol prints on their bottle of 30HD only to use in temperatures above 40F. I think their 40HD says 60F. So it doesn't take a lubrication expert, nor print on a bottle, to understand the effect monograde oils can have in colder temperatures. For those who are fairweather boaters, it's not that significant but for those who run in colder weather (I fish well into November in LI Sound) it is very significant.

I hope to buy some supreme #9000 5w-40 this spring. I will be running it in my 351w engine in my 24' if I ever get around to rebuilding the transom, and the 3.0L in my 19' along with the LS1 in the car and the 4.0L in the Jeep. UOA will follow, of course.

I run my 19' with the merc 3.0L 4-cylinder at 4000-4400 all the time skiing. So if schaeffer's 5w-40 shows a good uoa on that, they'll get a

from me.

 

[Vstrom]

I run the Mobil 1 Truck and SUV 5w-40 in my fourstroke Suzuki 70 OB that calls for 10w-40

So far so good

 

[Ryan00TJ]

I've always run Schaeffer 15W-40 Blend in my 21' Hammond Challenger. It has a built 360 Chevy Small block 425HP. I will be switching it to the Schaeffer 5W-40 when it comes out of storage.

 

[jimmbo]

I'm new here, but here's my 2 cents... Water/moisture in the crankcase is caused by the products of combustion, one of which is water. Some gets into the crankcase due to blow-by past the rings. When the oil temp gets hot enough the water will boil off. If the oil temp doesn't get hot enough the water doesn't boil off but combines with other compounds in the oil to make acidic compounds. Oil temps are much higher than coolant temps but low 160 degree water stats aggravate the issue by lenthening warmup time. The reason for the 160 or lower stats on marine engines is because raw cooling water is a chemical stew. At temps above 140 F minerals that are disolved in the water come out of suspendsion(undisolve) and tend to buildup in cooling passages. After many hours the waterjackets will look like someone ran some fresh cement thru the cooling system. Closed cooling system use a 180 or 190 degree stat cause they can run a water/glycol mix in the engine.

As for auto vs. marine operating conditions. Marine engines are worked much harder than auto engines. In a car, the engine is highest stressed during acceleration, once cruising speed is reached and the transmission is in Hi or OD the power required to maintain that speed had dropped dramaticly. Boats require consideratle more power to maintain speed because of higher friction and drag. Most marine engines and converted auto engines are designed to be low reving torque makers(less than 5000 rpm) rather the high rev HP makers.

Thinner oils help cool bearings better than thicker oils. Even though they will read lower pressure that thicker oil, more oil is getting to the bearings. As long the oil temp is lower than 300 degrees, the bearing clearances are proper and the pump can deliver enough oil, 5-30 is more than enough to protect an engine when used in a boat or tow vehicle.

Oils specificly for diesel engine do have higher shear restistance to handle the higher loads brought on by the diesels higher conpression ratios and method of combustion. This usnally isn't needed in gas marine engine. Detergent needs are different for deisels too.

[ April 29, 2005, 04:10 PM: Message edited by: jimmbo ]

 

[JonS]

Jimmbo, i think you are right on with everything except the 5w-30 thing. Do you really use 5w-30 Dino oil in a v-8 or v-6 marine engine? Isn't it just a 5 weight oil that behaves as a 30 weight when at 212f by adding viscosity improvers? i would think you would chew it up? Do you have experience with the 5w-30?

 

[DJ]

Oil temps can actually be low in the 4 stroke outboards due to water splash on the sump, an IO though I think oil temps should be good enough to burn off water well.

The sustained high revs really do make the engine conditions different than automobiles. My boat motor sees sustained 4500+ my car only spends a few seconds at a time above those speeds and I race it.

 

[jimmbo]

I was refering to synthetic 5W-30.

 

[BUBBA0420]

TWB: Don't you think that is too thin ????
I wouldn't put a 5w anything in a marine engine.
1. Your boat doesn't run at 212 degrees
2. Your marine engine is under 100% load at all times.
3. The moist environment they live in.
4. The long periods of non use in a moist environment
5. The high cruising RPM when they are used.
6. The high condensation rates due to cooling with a fresh supply of cold water (Unless you have closed cooling).
A Boat is not a car and is not a lawn mower.
That is why you have an owners manual so that you nay read it. No marine engine manufaturer recommends a 5W Oil.

 

[Geoff]

Volvo Penta specs a straight 30 weight synthetic (I have only seen this in the Volvo brand) for their engines, which use the same GM base engines as Mercruiser. The boat dealers here in Austin sell Amsoil 15w-40 marine/diesel.

 

[Craig]

Multi viscosity oils when they were first introduced did very poorly in marine engines due to their so so VII quality and the constant velocity type of operation in marine use. They would simply chew thru the VII's rather rapidly. So still today multi viscosity oils still carry that onus from years ago.

Since the quailty of VII's has improved so much I would not be hesitant to use a very high quality multi viscosity diesel engine oil that is also rated for gas. Get one with the "C" rating that is first on the letter ratings followed by the "S" ratings. This means the oil was primarily blended for diesel. These oils and their additives are very robust and resist shearback and should work great in a marine environment.
Personally in all my inboard boats I have used:
Amsoil Marine Diesel 15W-40
Amsoil Heavy Duty Diesel 5W-30
Amsoil Heavy Duty 30 wt diesel oil.
These were used in 2 boats with gasoline engines and the present engine which is a CAT turbo diesel.
My personal feeling is the best of the above is the HDD
Amsoil 5W-30 based on oil use. I cruise somtimes for
14 hours straight when traveling.

I am sure the Mobil Delvac synthetic diesel oils would be good too.
Craig