So Motor oil is not hygroscopic? That was my assumption. In the case of a vehicle that sits for long periods of time and being driven on short trips without reaching operating temp to burn off the contaminates should be the only time oil needs to be changed by date rather than mileage?

 

Education time: https://www.azic.com/moisture-in-oil...e-headedbeast/ More info about water contamination than you wanted to know. Bottom line is any amount of condensation left in the oil is deter-mental to the oil and the engine. Burning it off by running to operating temp and beyond seems like a wise practice. If you cant do that, frequent oil changes are recommended.

 

funny, I was looking for that article to post it....

 

An air cooled motor can run oil temps above 250* pretty easily, that would boil out any water out well before any damage would happen. Plus the generator engine's bearings aren't going to be cut nearly as tight as a truck engine, so pressure issues during the cold starts aren't going to be a problem in terms of engine damage, you'd actually be more worried about the opposite: maintaining pressure at high oil temps with a sustained high load factor.

Temps are also part of the reason why commercial lawn mowers/small engine equipment run 30W oils instead of 20Ws like modern car engines, at the much higher temps they see the heavier oil is better. It's also why companies like (IIRC) Scag specify straight weight dino oils and not multi-visc synthetics, since there is (again, IIRC from BITOG) a difference in base oil weight of multi-visc synthetics vs. dino.

Big difference in a 6.2 and a Kohler twin (I know you know this, but for sake of argument). For the 6.2 the multi-visc oil and additive package are a huge part of prolonging cam and bearing life, turning 5k RPM with a greatly variable load factor. The Kohler can use the same oil as the truck engine, but would probably also run fine on straight 40 weight non-detergent dino, at least for a hundred hours or so. The 6.2 would probably eat it's bearings or blow it's seals on a cold start with straight 40 weight. I'm thinking your generator and Kohler are fine because their design tolerances are significantly looser so oil problems that would cause pretty immediate damage to a modern auto engine won't phase them.

 

Damn good read, thanks for the education!

 

99% of the info on OCI's in any thread on the interweb is urban legend and old wive's tales.


The only people who have a leg to stand on are those who are sending an occasional sample to Blackstone for actual, scientific data. On my recently acquired 2011 6.2 I plan to go at least 6000 miles unless Blackstone data suggests otherwise. If they say try longer, I certainly will.


We go 10k in our 2005 Yukon and it's perfect per Blackstone.


Most people change their oil WAY too often and believe me, the oil companies love you for it. It's something that makes people feel good but if you really want to be pro-active about preventive maintenance keep a close eye on brakes, u-joints, ball joints, belts. Many, many hard parts get overlooked while people wastefully change their oil every 3000 miles.


And if anyone is wondering if Blackstone ever issues a "bad" report: YES they do! I've had two samples (one of which was not my fault as I did not own the vehicle at the time) tell me, "whoa, you went way too long."

 

Diesel: 5-7k miles or once a year due to oxidation which can cause pitting, contamination, moisture and additive breakdown.

 

I guess I'm missing something, why would folks not change the oil at a minimum when the truck tells you to or if you have an earlier truck when the owners manual tells you. And then for $20.00 send a sample to Blackstone for analysis. Shortening the change interval I get, I do it myself, you're trying to make sure the oil is doing what it's supposed to. You may be wasting a bit of money but you're not hurting your truck. Without a bypass filter system I'm not sure I get extending the interval. Remember, you're also extending the change interval of the filter - with the dirt that gets in via the air intake system and the crap the egr system is dumping in the oil, the filter has got to be under a bit of stress at the regular change interval, extending its life has got to be resulting in the automatic bypass kicking in resulting in unfiltered oil being put back into circulation.

 

Yes, basic understanding of driving style classification using the Oem's criteria and following the appropriate maint schedule.

So if the"book" says my driving style is extreme duty and I should change at 2500, it's quite possible that if I do oil sampling my oil will still be good and I might be able to get more use out of it...

 

This is the crux of the "changing too soon is fine" side of the argument; if the dollars and cents aren't your main concern then there is pretty much no downside to shortening the interval, or using a more strict maintenance schedule. So it gives me a warm fuzzy and makes no difference to do two 5k OCIs a year instead of one 10k one (it's also very, very arguable on the 6.0 that a 10k OCI is damaging the injectors, supported by many UOAs); I pay a lot more for warm fuzzy feelings from stuff like insurance than I do in oil changes, and I like the warm fuzzies so lemme alone about 'em

I'm not going to make a technical argument about I because I look at it as risk mitigation; I pay a little more to change oil in my three vehicles on a conservative schedule so I don't have to even spare a thought on if the oil is too old or deal with repeated lab samples and analysis. Flat-out don't care, no one's going to change my mind with an argument about it either. Flip side is I won't give a hard time to a guy with an Amsoil filter setup getting three UOAs per change done trying to eek out every last mile. His UOAs show a lot of great info, and I'm happy for him that he thoroughly enjoys doing it apparently.

And since it's been brought up that other systems are important, apparently I need to confess to my annual brake fluid change habits as well. The guys at Discount Tire are also nice and let me do brake inspections while they're balancing the tires every 10k miles. Anyone want to argue about tire rotation intervals next?

 

More oil changes = more dry start ups

 

I agree with everyone on both sides here.
Change oil as often as you want. or infrequently.

I bet we all agree that it's "too long" when the oil is dark colored.

I would change mine more often if I had more time to spare. True of all my vehicle maintenance.

Tire rotations would be great to do more often too. Every 1,000 miles would probably be optimal.

 

That's an interesting thought. Sometimes I fill my filter with oil before I screw it back on.

I wonder how bad of an issue this really is.

 

I don't think it is but I recently went from 3,000 to 5,000 mile oil changes and used that to help justify it.

 

Mine is black about 5 minutes after it starts running again Damn dirty diesels.