I changed the oil on my engine a couple of months ago and didn't have enough for a complete fill. Sometimes I will use 30 weight and other times 10W30 depending on what a given store has available. Several days ago I went to buy another quart to complete the fill and realized I couldn't remember if I used 30 weight or 10W30.
I always thought it was bad to mix different weights of motor oil so I emailed Universal to explain my problem. Their response was "No real issue here. Add 10W/30 or a W30. They will mix."
What are your thoughts?
My thought for what its worth. Mixing brands or weights of oils wont make make a difference, in the short term. Find out what works best for you and you have the most confidence in. Change that only if necessary. Then change back when convenient. If all the little things are taken care of just right our engines should last decades. Just my 2bits.
I always thought it was the brand that mattered not the weight of the oil. Unique additives by manufacturer was the reason. Probably BS. Like everything else, I'd guess most refineries make it for several different brands.
I always subscribed to the theory of never mixing weights...unless absolutely necessary. Some of the wrong thing in there certainly has to be better than none of the right thing :D
Mixing oils is fine, although Ken raises an interesting point about additives. The one thing you must not mix is standard diesel oil versus synthetic diesel oil. Regular oil and synthetics don't mix. I'm not sure how bad the consequence is of mixing, but it's definitely a no-no.
Up here the standard seems to be 15W40 diesal oil for our engines. Some brands actually say "Diesal 10W40" on the container. The key is that it has the CF4, CH4 etc. designation I believe.
I put 10W30 in once and was told it wouldn't harm the engine but I might see some oil leaking. After a week I couldn't stand the uncertainty and so went down to change the oil again.
Any thoughts?
Hawk
Quote from: Hawk on February 19, 2009, 01:44:09 PM....and was told it wouldn't harm the engine but I might see...
Hawk, that kinda "quote" is what drives me up the wall. Who told you? What "credentials" did he or she have? What backup to this unsubstantiated rumor did it come from? If you get information from this board or others, you can at least quote us by name. :D I, personally, wouldn't listen that kind of potential nonsense and get concerned about it without doing some more checking (OK, I get it, you came here, good on you!).
10W30 is just fine stuff. I use 30W. Synthetic Mobil 1.
After Stu's post, it seems appropriate to bring up the synthetic vs. conventional oil question...
If you change it every 100 hours, is synthetic worth it?
Stu,
It was the local marine engine shop at the marina who told me and a highly regarded diesal engine mechanic (unrelated to the shop) who recommended the 10W40 as did the PO and others. Maybe its another quirky Canadian thing.........
I'll check into it further and report back. I'm sure that it likely doesn't matter at all. These diesals probably run fine with vegetable oil in them :)
Hawk
Ken : I've uesd Mobil 1 for well over 40 years in my autos and over 20 yrs in my C34. The advantage of a synthetic over a conventional oil is that a synthetic doesn't "wear out" it gets dirty. Conventional oil does both. Getting close to 100hrs and the end of the season and using a synthetic? Put on a new oil filter and go till haulout!
I've talked to the Mobil 1 engineers and asked about mixing two 10W30 with two 15W50 and the engineer said " You're trying to make 10W40, and I replied - yes". He said that was a great way to do it and there would be no problem!
I quote from a Mobil 1 bottle "fully compatable with engine seals and conventional oils".
I'd say .... Dah , but that wouldn't be polite. A few thoughts.
Quote from: Hawk on February 19, 2009, 06:39:11 PM
Stu,
It was the local marine engine shop at the marina who told me and a highly regarded diesal engine mechanic (unrelated to the shop) who recommended...
Nice to know where it came from. He's probably more trustworthy than I am, eh? :D :D :D
Sorry, not 10W, I meant 15W40. As for trustworthy, I'd wager you have him beat, Stu.
I'm still checking on the oil specs...........
Thanks for straightening me out Ron! :thumb:
the standard oil used in all major trucking companies for there macks, cummins, dd, cat and i/h motors is 15w40. it is multi weight,or viscosity, so it thins down to 10w in cold and thickens up to 40w in summer. i only use straight 30w here in n.e. as it is such a short season and we don't need multi vis oil here. mixing oils is ok but never syn. with regular and there is a difference with manufactures additives. buy one type of oil and stick with it. spring is coming. i just attended the boston boat show and saw the 375 catalina. what a boat...jeff
Jeff, thanks for your post, don't know if you've seen this one about the 375: http://c34.org/bbs/index.php/topic,4232.0.html
Jeff,
Alot of folks seem to recommend Rotella. Do you know if it is any better than any of the other std oils?
"Favorite" and "best" oils, Ken, is almost like asking about the "best" anchor. It's just one of those things where each skipper has his favorite that works for him. Many love their Rotella.
I totally agree with you Stu. Jeff's in the business, his opinion might carry a bit more weight.
ken, the most popular brand is shell rotella 15w40, the industry standard. if it is recommended for a 525hp cat engine, trust me, we can use it in our little 3 bangers. i use delo, chevron, sae30w as mentioned above, because i don't need a multi vis. oil. for those of you who enjoy a longer season and want a multi grade oil, go for rotella, if its available, if not i recommend a high quality, brand name oil or, as ron mentioned,mobil 1 syn. oil. but remember, if you use synthetic oil, stay with it...jeff
one thing i forgot to mention, which may be obvious or not, when buying oil, especially at an auto parts store, read the container just to make sure you see the words,for use in diesel engines. you'd be surprised how many brands are not diesel approved, meaning of course, for gas engines only. for what it's worth...jeff
Cruising World magazine just happens to have an article in the March '09 issue re: choosing an oil. See link:
http://www.cruisingworld.com/how-to/maintenance/choose-the-right-crankcase-oil-1000069397.html
Jeff/Stu,
As I said earlier, out west where the boat is in the water year round, the standard oil used is 15W40 specified for use in diesal engines. Also you want to check the API Seal rating on the container to be sure, as I said, that the oil is rated as one or more of CF4, CG4, CH4, CI4. The lettering has changed over the years. The cruising world article above explains it.
Hawk
I think it's much more important to use a diesel specific oil, or "C" rated oil, not one made for gas engines with an "S" rating. Sticking with a brand (additive package) is also somewhat more important than to worry about mixing weights.
This is conventional Rotella T 15W-40 at 2800+ hours of engine use..
(http://www.pbase.com/mainecruising/image/109136073.jpg)
Valve cover un-cleaned and as removed:
(http://www.pbase.com/mainecruising/image/109114477.jpg)
You don't need to over think this. Wal*Mart is the low cost distributor of Rotella T in 15W-40. While your engine will take either a diesel grade 30 weight or a 15W-40 you won't have as much luck these days readily and consistently finding a straight 30 weight diesel grade oil. When you do it will be more expensive than Rotella T 15W-40 from Wal*Mart..
Wow! I doubt I would get the same clean look if I pulled the valve cover on my 1300+ hours engine. The PO used conventional 30W oil - I continued with the same the past season. I think these pictures just found a convert. :clap
Guys, Susan & D : The biggest problem that the early Universals have is that you can not get all of the dirty oil out ! Seems that the oil drain is in the front of the oil pan and to make things worse the engine is tilted back.
The newer Universals have the oil drain in the rear of the engine. If you ever have your M25/35A engine out of the boat - move the oil drain to the rear and put a plug in the front drain.
The largest difference between a "C" and a "S" rated oil is how that oil & additives suspend the dirty particulents. That's why it's important to use "C" rated oil in a diesel. Both grades oil lubricate, but it's the "C" additives that better suspend the dirty stuff (learned that from a Mobil engineer).
A few thoughts.
Don't use only "S" oil.
Use "C" rated oil.
Read Cruising World's latest Steve D'Antonio, nothing new there, but he does mention it.
Engine Oil Basic 101.
Read the bloody label.
Please. It's YOUR engine.
As long as we are talking oils. What are the thoughts on additives. I have used Lucus products and been very impressed in other applications. The sales story that I believe is that most wear happens at start-up. With no oil pressure the only lubrication is what ever oil is left on the surface. It's believable, but it's hard to tell, our engines will last a long, long time with just average maintains. I haven't started using an additive in my new to me boat, but am planning to this season. I could change my mind if others have had problems.
Only about 2 more months to make that decision when I restart the engine.
Ron and all,
As stated by Ron, my vintage C34 has a drain plug forward with the engine tilted up leaving residual oil in the back of the pan. In order to convert to Rotella T, do you recommend dropping the pan to remove this residual volume and letting all the oil drip out of the engine as well? I realize you should not mix both types of oil.
Also, I've heard the superior cleaning ability of synthetic oil (evidenced by the photos) may cause other issues in an older engine, e.g., leaks in seals and cyclinder blow by (reducing compression) when all the gummy plugs in the engine are very well cleaned - as in it cleans too well. Can anyone comment?
Quote from: albreen on February 24, 2009, 07:36:13 AM
Ron and all,
As stated by Ron, my vintage C34 has a drain plug forward with the engine tilted up leaving residual oil in the back of the pan. In order to convert to Rotella T, do you recommend dropping the pan to remove this residual volume and letting all the oil drip out of the engine as well? I realize you should not mix both types of oil.
Please lets not over think this. If you want to get rid of that residual oil or seriously dilute what's left, you can simply do two oil changes. This beats dropping the pan down for sure. Mixing an S & C with 95% of it being C is far better than using 100% S rated oil.
Quote from: albreen on February 24, 2009, 07:36:13 AMAlso, I've heard the superior cleaning ability of synthetic oil (evidenced by the photos) may cause other issues in an older engine, e.g., leaks in seals and cyclinder blow by (reducing compression) when all the gummy plugs in the engine are very well cleaned - as in it cleans too well. Can anyone comment?
If you want evidence with photos look at the photos in post #22 above. Again this engine has 2800+ hours of run time with CONVENTIONAL Rotella T and looks like brand new. How long will it take you to get to 2800 hours, 10, 15, 20 years or more?? This engine has NEVER had even one drop of synthetic oil in it nor any additives.
I bought into the synthetic thing big time years ago. Most of my cars were converted with 80K miles or so on them. Within weeks of conversion I would always have major oil leaks. When I say "leaks" it was usually more than one so I know it was not just a coincidence. Synthetic oil makers say this does not happen anymore but I personally don't buy it with an older engine. Unless you are converting shortly after break in why risk it when conventional oils will work perfectly in a small aux diesel? Rotella T 15W-40 is a great oil and needs no additives to take a marine engine to well over 2800 hours and keep it very clean..
On thing I do before winter is to do the double oil change. One new filter but a double oil change with a 15 minute run in between. My engine burns zero oil and consumes none between changes..
Sailboat engine deaths can usually be blamed on short run times that never completely burn off start up condensation. If you want to prolong the life of your engine focus on your engine running times...
P.S. My brother commuted from Maine to Boston for years in a Honda Accord the car finally wore out, rust killed it, with 325k miles but not the engine. The engine was still going strong and had only ever had conventional oil put in it. Oils are so good these days that engines just do not wear out anymore..
My error - I thought Rotella T was a synthetic oil and the photos showed the cleaning results due to its use. I reread the thread and it does say 'conventional'. Regrets..........
Mainesail,
I take it the double oil change really cleans it out. Can you expand on the merits of the double change.
Hawk : My experience is that after a single oil change you start up the engine, check the oil and you'd never know that you just changed oil ! I remove the engine (for other reasons) drained the oil, started the engine (after it was back in the boat) and the new oil "look" lasted only about 25 hours before it was pitch black again.
Bottom line is "It's the nature of the beast" that diesel oil gets really black if you leave it for 100 hrs. That's why diesel oil has a "C" rating so the suspended particulates do not damage the parts that it is lubricating.
Thanks Ron. Do I take it that you also perform a double change once a year?
I don't want to speak for Ron but in my experience the oil turns black after the first engine use no matter what. My oil pan was rusted out and even after I changed it out, the oil was black after the 2nd use. So, botom line is, as long as you change it on a regular basis, black oil is OK.
Mike
guys here's the deal, in lay terms and not getting overly technical, in a diesel engine, when you change the oil and then start and run the engine, the oil will turn black in just a short period of time. this is because carbon, black, is produced when the diesel fuel is combusted in the cylinder heads. some of it gets washed down onto the cylinder walls and eventually, the carbon sticks to the cast iron block. it is the oil that lubricates the cylinders and cleans the carbon deposits from the block. if the oil does not turn black, the oil is not doing its job. also, as mentioned above, you will never get all the oil out of the pan, so the new oil will mix with whatever was left behind...jeff
I would NOT recommend changing to synthetic oil in an older engine. Infact most experts (not your local mechanic) recommend that you use regular oil thru the 25 - 100 hr break in. Then you switch to synthetic oil - NOT later on.
As someone mentioned in a previous post, you'll incur oil leaks if you switch to synthetic in an older engine or transmission. Be-where !!