Oil change intervals for geeks

[booster]

Another thread, with the all so familiar opinions about how often you should change you oil, reminded me to go back and look at some information that I hadn't looked at for a while. Most of this is from the Bob is the Oil Guy site, which probably has some of the best tech information around, but is also loaded with a lot of personal opinion stuff, too, so you have to filter.

I am data driven by nature, as are some others here, but also have influences of lots of personal exposure to some of this stuff in a lot of my hobbies and work life, so they sometimes get mixed in.

As was mentioned in the other thread, without actual data the discussion is going to never be resolved for anyone. IMO, nobody is going to be tearing down engines every 10K miles and measuring everything, or running controlled parallel testing for 100s of 1000s of mile to get valid data. That leaves only the indirect data to look at, which is primarily used oil analysis (UOA) for healthy engines, or oil consumption for less than prime engines.

Here is a very good article that explains the UOA and what to expect and learn from it:

https://bobistheoilguy.com/forums/ub...no#Post2780790

I will add that I think that our RV use might be a bigger influence than a lot of the data the article used, in particular cold starts, storage in various conditions, and extended idling for those with engine generators and autostarts. For those reasons, I think it is needed to spring for the extra cost TBN and acid checks to make sure the additive package is still intact and there isn't acidity that can erode things, particularly bearings when sitting for extended times. Dilution, both from water and fuel, may also be much more prevalent among us, than the rest of the driving public.

There is also a thread on Bob is the Oil Guy that does nothing but list UOA results that folks have done. You can go through them and see what the various change intervals, oil and filter types, etc look like on pretty much any engine made, I think. Interesting read for me to be sure. I just went over a bunch of them and found that the early information about the now low levels of zinc in the SM and later oils isn't behaving as was predicted, at least in the rollerized engines. Zinc was always said to be a consumed additive that would deposit on the sliding surfaces and protect them, so it would be continuously depleting as miles built up, until it got to levels of no more protection. The old cure was to put a bunch in to start, so it was always high enough at the end. What the UOAs are showing is that the zinc is not depleting with miles, and staying essentially where it started at the oil change.

For gassers:

https://bobistheoilguy.com/forums/ub...sis_-_Gasoline

For diesels:

https://bobistheoilguy.com/forums/ub...lysis_-_Diesel

Perhaps we should have a similar thread here where folks can post their UOA results? I think it could, at least, start to fill in the blanks between opinions and the real world

[Roxy4x4]

Nice. Thanks for that.

So after review, are you brave enough to tell us what you are doing with your gas and diesel engines for change intervals? No judgements just sincerely interested.

[mkguitar]

follow the manual...buy correct spec stuff, stick with the same brand when you can

magic fluid additives won;t fix a mechanical problem

pay attention to severe or heavy duty intervals-

oil IS part of the cooling system, removing heat from the hottest parts of the motor ( combustion chamber, bearings) and carrying the heat away to be dispersed to the liquid cooling system and the air

2¢

Mike

[avanti]

Originally Posted by mkguitar

follow the manual...buy correct spec stuff, stick with the same brand when you can

magic fluid additives won;t fix a mechanical problem

pay attention to severe or heavy duty intervals.

Hear, hear!

[BBQ]

.

Miles driven is only one of the measurements for oil change interval.

If you idle your engine (eg. with the underhood generator), you should change the oil more often.

[BBQ]

https://www.youtube.com/watch?v=KEhxfvm7ROM

[mkguitar]

I use only syn usually mobil 1 on modern motors ( I have old stuff and that uses the dino-oil)- a Pal who worked as an wholesale auction inspector showed me a neat trick they use.

Look at the underside of the oil filler cap- an abused, heated or motor on dino oil will show deposits of varnish on the cap.
a motor is good shape will not -esp with syn

Mike

[booster]

Originally Posted by Roxy4x4

Nice. Thanks for that.

So after review, are you brave enough to tell us what you are doing with your gas and diesel engines for change intervals? No judgements just sincerely interested.

Absolutely, no problem with that at all

All of this is also based on the fact that we live in the Tundra, about 30 miles north of Minneapolis, so we see cold. All the vehicles do get parked inside, with only the CRV in semi cold attached garage, the other garage is always 40+ degrees. We are both retired so the miles have dropped huge from the 18K I used to do and the 15K+ DW used to do.

DW's 2009 Honda CRV at about 35K miles is now getting 4-5K per year. We normally share the CRV in the winter, but I have my own vehicle in the summer or winter when we need to both go at the same time. CRV was always on Castrol GTX dino oil when commuting and changed at 3500ish miles. Now with the low miles it is on the plain Mobil 1 synthetic and changed every late fall and early spring. 5W30 all year.

My 1996 Buick Roadmaster wagon, 5.7l engine, 128K miles, only picks up about 2-3K miles a year. It gets the plain Mobil 1 once a year just as it gets parked for the winter. I have only had it 3.5 years, so I don't know what oil it had before, but it was clean when I got it and didn't get dirty quickly, so it appeared to have had very good care, and uses no oil at all.

The 2007 Roadtek 190P Chevy is totally random based on conditions and how we will be using it. If I know I will be needing to move it in and out of the shop a bunch of times in the winter, I usually will just put in some Castrol dino oil in the fall, and change it out in the spring, as I know it is going to get moisture in it moving in and out a bunch. If it is just going to sit over the winter, I change it to one of two options. If we are going to be doing just somewhat local trips without mountains or horribly hot weather or high speeds, I use the plain Mobil 1 5W30 and usually it will have 3-5K miles on it by the end of summer when it gets changed for parking. If we are going on a long trip, with mountains, higher weight, faster speeds, hot temps, I will put in Redline 5W30 group V synthetic. It has the best temp tolerance of most anything I have found and a very robust, high mile, additive package. We have run it up to 7500 miles of what I would call quite severe use. If we were going longer than about that many miles, I would get the oil changed while on the road, and use Mobil 1 extended, or the extended Amsoil extended mile version. I don't want to carry 6 quarts of of oil, and Redline is very hard to find most places.

As you can see, we change mostly do to time and contamination, not miles or use, on our drivers. The synthetic is just do to the extended time, and we drive so little, the cost is very small of an increase. If we were commuting them, both the drivers would be on Castrol dino oil. My 1992 Escort went 210K miles on Castrol dino, and went to the junk yard still able to go 10K miles without adding oil.

The van is based mostly on conditions, with a bit of conservative hedge on miles. It has never had the monitor trigger. Chevies run hot for a lot of people, so heat tolerance is a high priority. Time will tell how it all works out, but at 37K miles it is not using any oil.

We don't have any diesel stuff, and never have, so no history on that. My opinion would be that it is not the miles that are going to be the big issue, although 20K, is a lot of miles, but having as much oil capacity as MB uses certainly helps. What I would be watching in modern diesel would be the contamination issues from water and fuel. It definitely says something when they put a high oil level alarm in so it will go off if you get too much dilution in the oil. Blackstone puts high limit at 2% oil dilution, others have said you start to see significant viscosity change at 1%, and that is not much volume. It would be interesting to see how much dilution there is when the high oil alarm goes off. Idling for long periods, especially if it is in the cold like we saw a lot of people doing at Wendlunds winter camping trip, or even worse, repeated winter recharging idles while boondocking would, for me, generate the need to take an oil sample, and watch the oil level, until I knew if it was an issue or not.

I do find it refreshing to see that a fairly large amount of people are taking into account use patterns in their decisions, as it just makes sense to me.

[Boxster1971]

I just looked at the Bob is the Oil Guy site. I couldn't find a search function, did I miss something. Those forums would be hard to use without a search function.

[booster]

Originally Posted by Boxster1971

I just looked at the Bob is the Oil Guy site. I couldn't find a search function, did I miss something. Those forums would be hard to use without a search function.

It appears that the search function only shows up if you are a member and logged in. IIRC, very easy to sign up there.

[BBQ]

Originally Posted by Boxster1971

I just looked at the Bob is the Oil Guy site. I couldn't find a search function, did I miss something. Those forums would be hard to use without a search function.

if you are using the chrome browser, you can do your search this way


site:www.bobistheoilguy.com keywords

keywords being any word you want to search

[mkguitar]

Originally Posted by BBQ

site:www.bobistheoilguy.com keywords

or paste into any google search window

mike

[Boxster1971]

Thanks BBQ and mkguitar for the tip. I forgot you can use the Google site search to find anything on a specified web site.

[booster]

It looks like I got the wrong link in the very first post, although you could still get to the article from the first post in the link.

Here is the actual article link

http://www.bobistheoilguy.com/used-o...hat-is-normal/

[dknightd]

I change oil once a year. so far so good. If I did more than 10K a year I might change it sooner. Follow the instructions. Assume you are a severe user.

[BBQ]

https://www.youtube.com/watch?v=EZcN4vIv0dU

[booster]

I think that story is a bit behind the time, but not bad information. 200K with a modern car is not a big deal anymore. Most will make nearly that with poor maintenance, and most don't really start showing their age until about 170-180K. That story probably could have been titled 250K or even 300K and been pretty accurate, especially for warmer climates.

The recommendation to change oil at book recommended and trans and coolant more often than book IMO was good, and could also include brake fluid and power steering fluid.

There was a 2007 Chevy Express box truck on the Minneapolis Craigslist the other day that had over 400K on it. It didn't say if it was gas or diesel, but it looked like a gasser.