Simple question about oil changes.
Post Fiend
Joined: Jan 2006
Posts: 20,589
Likes: 2
From: Charlotte, NC
I don't know......Sounded like the thrust of his last post was to say that semis are towing heavy loads every day and they change THEIR oil at 20000 miles....some of them at 52000 miles......which I deduce to mean that heavy towing does not prompt a shorter oil-change interval (he responded to my assertion that frequent towing will prompt this shorter interval).....Soooooo....for all you "towing" experts out there (driving 250s and 350s....NOT semis).......Does frequent towing demand a shorter oil change interval?........Or not?..........I'd say it does.......And on the 1st page, me and the "Monster" showed similar oil-change intervals (7500 miles)........I'm not necessarily a big believer in the "3000" club either......Unless it's severe duty (police, fire, EMS...etc.)....OR frequent towing.
Peace
Peace
Post Fiend
Joined: Jan 2006
Posts: 20,589
Likes: 2
From: Charlotte, NC
Originally Posted by monsterbaby
compd, the last 2 posters hit on part of my point, I forgot to add one part to my post, and clux hit it to a certian extent. around 10 yrs ago conventional wisdom on a semi was to change the oil at approx 12k miles, but with the UOAs being done on these trucks a lot (the owners of trucking companies figured out that $20 for a UOA that lets you decided if you can extend a oil change that costs around $190 each time is pretty cheap insurance) it's been figured out that 12,000 miles was WAY too soon and was a waste of money. So now even the OEMs have almost doubled thier recommended oil change intervals even with convenctional oils, but the light truck and passenger car markets have not followed suit even though they have the same issues.
Yes Semi's are a little different, first they carry in my case 37qts of oil and 3 oil filters, but mainly everytime that truck is started it rarely goes less than 500miles before it is shut down again. But that fact is partly why they used to recommend 4 times the oil change interval as lighter duty trucks, but with analysis they have gone to almost 7 times the recommended of light duty trucks, and the owners of these vehicles have figured out that is even too soon and have in some cases even doubled that. 3000 miles is fine but it's not gaining you a single mile on the back end of your vehicle from what has been seen in testing the oil, you are litterly throughing away money staying with that change interval.
OH and I wasn't trying to slam on anyone especially you compd, just clearing up what I meant since your post brought up where I left some things out.
Yes Semi's are a little different, first they carry in my case 37qts of oil and 3 oil filters, but mainly everytime that truck is started it rarely goes less than 500miles before it is shut down again. But that fact is partly why they used to recommend 4 times the oil change interval as lighter duty trucks, but with analysis they have gone to almost 7 times the recommended of light duty trucks, and the owners of these vehicles have figured out that is even too soon and have in some cases even doubled that. 3000 miles is fine but it's not gaining you a single mile on the back end of your vehicle from what has been seen in testing the oil, you are litterly throughing away money staying with that change interval.
OH and I wasn't trying to slam on anyone especially you compd, just clearing up what I meant since your post brought up where I left some things out.
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
typing at the same time, I did respond again just before you did. The thrust was about the towing but was meant that those engines are used hard all the time, and they are finding that changing it even at OEM recommended oil change intervals is too soon.
but one thing to remember, I don't believe working a diesel hard increases the need to change the oil sooner, rather I believe the opposite, if you check the UOAs of something like say a school bus that actually isn't pulling that heavy for a diesel I think you will find that 20k+ miles is actually pushing it. And example when I was still farming I had 2 tractors both running 361cid international diesels engines, both had around 7000hrs on them, one was turned up a little more than the other but really not relevent but what is relevent was one was used for chores mostly, hauling hay out to the cows, running a bushhog mower, and other light duty stuff like that, the other tractor did the heavy work like running my 4-1/2 ton grinder, plowing, towing grain etc when I would change the oil in those tractors the one that did the light duty work always seemed dirtier ( I never did UOAs on them, but the oil felt gritty and looked and smelled dirtier if you know what I mean). Another way to look at this is watch the temp of your oil when your running empty sometime, you will see it doesn't get much over 190degs usually, but start pulling a load, and watch it (you can sort of see the same thing on the water temp) it will climb over 200 degs, well the water won't start boiling out of the oil before 200deg and that water is a big part of why they make the 3 month recommendation as you will always get condensation in your oil to a certian extent if you don't boil it out it will build up over time, but a diesel motor will boil it out if it's worked hard. Gas motors are a little different.
Ah I think we are seening eye to eye now after you added the second post.
but one thing to remember, I don't believe working a diesel hard increases the need to change the oil sooner, rather I believe the opposite, if you check the UOAs of something like say a school bus that actually isn't pulling that heavy for a diesel I think you will find that 20k+ miles is actually pushing it. And example when I was still farming I had 2 tractors both running 361cid international diesels engines, both had around 7000hrs on them, one was turned up a little more than the other but really not relevent but what is relevent was one was used for chores mostly, hauling hay out to the cows, running a bushhog mower, and other light duty stuff like that, the other tractor did the heavy work like running my 4-1/2 ton grinder, plowing, towing grain etc when I would change the oil in those tractors the one that did the light duty work always seemed dirtier ( I never did UOAs on them, but the oil felt gritty and looked and smelled dirtier if you know what I mean). Another way to look at this is watch the temp of your oil when your running empty sometime, you will see it doesn't get much over 190degs usually, but start pulling a load, and watch it (you can sort of see the same thing on the water temp) it will climb over 200 degs, well the water won't start boiling out of the oil before 200deg and that water is a big part of why they make the 3 month recommendation as you will always get condensation in your oil to a certian extent if you don't boil it out it will build up over time, but a diesel motor will boil it out if it's worked hard. Gas motors are a little different.
Ah I think we are seening eye to eye now after you added the second post.
Post Fiend
Joined: Jan 2006
Posts: 20,589
Likes: 2
From: Charlotte, NC
Originally Posted by monsterbaby
Ah I think we are seening eye to eye now after you added the second post.
Posting Guru
Joined: May 2006
Posts: 2,274
Likes: 1
From: Milroy, PA
Another thing we are not taking into consideration, the improvements and advancements in BOTH oil and motors. Pretty much since cars were made till around 40 years ago it took lead in fuel for the valve seats to last, with new motor designs, and improved oil, we dont need lead anymore. I understand thats a gas motor but its an example, motors are cleaner today and oil is better.
There was a time when oil changed were infact needed at EVERY 3k if not sooner
There was a time when oil changed were infact needed at EVERY 3k if not sooner
Thread
Thread Starter
Forum
Replies
Last Post
CheaperJeeper
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
48
May 22, 2009 08:05 PM
OSin86
General Automotive Discussion
52
Jan 15, 2006 11:04 PM
