Fuel filter advice

luvrbus · September 25, 2016, 02:05:10 PM

Detroit has always based the oil change on the sulfur content in the fuel with today's fuel he is good @ 15,000 miles when they used #1 fuel the truckers changed every 20,000 miles.I always changed mine @ 10,000 to 12,000 miles or 1 time a year.
Once upon a time DD came up with a brain storm and offered a 100,000 mile oil changes if you equipped the engine with their special by pass filter needless to say that didn't last long, the warranty work was killing them.
These new diesel engines are amazing changing the oil at 40,000 miles and it still looks new

chuckdrum · September 25, 2016, 04:45:12 PM

Thanks, all, for your input. Y'all kinda got off on the 'oil change in cars' tangent rather than the fuel filter change frequency on a DD, but thanks anyway! I change the bus oil every 15K because that's what the PO recommended and he seemed pretty diligent about maintenance. Considering I add a gallon about every 1200 miles or so, I figure it gets a lot of fresh oil over the course of 15K.

Thanks for the fuel filter changing tips. If I lose prime, I'll probably be back to ask you about that!

Chuck

Oonrahnjay · September 25, 2016, 04:59:31 PM

Quote from: chuckdrum on September 25, 2016, 04:45:12 PM.... Considering I add a gallon about every 1200 miles or so, I figure it gets a lot of fresh oil over the course of 15K. ...

"Total loss lubrication" -- if it worked for a 1911 Harley Davidson, it's gotta work for us, right.

DoubleEagle · September 25, 2016, 06:05:12 PM

Wow, the oil change intervals are all over the place. The last long-term tractor-trailer I drove had a Cummins ISX, and the company I drove for changed it every 25,000 miles with 15-40 conventional oil. I put 740,000 miles on it, and then they gave me a new one, but there was nothing wrong with the old one. My company's Powerstroke 7.3L dually pickup gets changed every 5,000 miles, with only 200,000 on it now I expect much more use out of it.

TomC · September 26, 2016, 02:31:37 PM

My 1984 Mercedes 300 Turbodiesel has a suggested oil change of 5,000mi. I've been changing it every 3,000mi. Because of that, the normal ring job around 250,000mi was eliminated, since, my mechanic believes, I have been changing the oil every 3,000mi. My car now has 502,000mi and still running on original engine.
New trucks running over the road with Detroit DD engines have a 50,000mi oil change-along with the filters. Good Luck, TomC

Scott & Heather · September 26, 2016, 08:08:57 PM

My 1998 Toyota Camry: changed oil every 15,000 miles with Mobil 1 extended performance and matching oil filter. Sold it at just under 300,000 miles. Still driving around in Berrien springs Michigan.
Current vehicle: 1998 Land Cruiser 100 series with 4.7 liter v8. Changed oil every 15,000 miles Mobil 1 extended performance and matching oil filter. 240,000 miles and going strong. Don't waste your money on 3000 mile oil changes.

Sent from my iPhone using Tapatalk

Dreadnought · September 26, 2016, 09:00:44 PM

Its very difficult to compare a modern petrol engine to a diesel- in terms of change interval.

As an engine designer I understand this implicitly.

For a petrol engine- the change interval is a function of oil capacity to engine capacity ratio and how quickly the engine warms up (cold start rich fueling finds its way into the tank) and also the ambient conditions when the engine is run.
The temperatures a petrol engine runs at are much higher than a diesel- particularly compared to a heavy Duty diesel.

For a diesel- the more modern diesel engines have post injections- and this diesel often finds its way into the oil sump. Diesel is a lowsy lubricant compared to oil.

For the Detroit engine- it is a diesel 2 stroke. At low rpm- the way the super charger is matched on the Detroit (scavenging) along with the combustion system design- the engine typically black/grey smokes on lugging. This is BAD for oil lubricity properties. Fortunately an old Detroit doesn't have to contend with post injections of modern after treatment systems. CHap who posted above about lower suphur in fuels is also quite correct. In addition diesel engines such as ours like low ash.

I would go with the 10-12 K interval. Its mileage dependent not time. The oil system is sealed. If that oil wasn't sitting in your rig during storage- and in a can instead- as yourself- would the oil degrade?

chuckdrum · September 27, 2016, 11:49:44 AM

FYI, fuel filter change was quick and flawless, using both the fuel shut-off reminder and the 'start it up between the two filter changes' concept. No loss of prime. Still purrs like an oversized kitten.

Now, to try to get that pesky oil pressure gauge to work...

Iceni John · September 27, 2016, 12:59:29 PM

Quote from: Dreadnought on September 26, 2016, 09:00:44 PM
Its very difficult to compare a modern petrol engine to a diesel- in terms of change interval.

I would go with the 10-12 K interval. Its mileage dependent not time. The oil system is sealed. If that oil wasn't sitting in your rig during storage- and in a can instead- as yourself- would the oil degrade?

I was told that oil becomes acidic inside an engine, even when the engine's not running. Is this true? Also, do the additives slowly precipitate out if the oil sits undisturbed? These are just two things I've read, but who knows if there's any truth to them?

John

Lin · September 27, 2016, 04:31:28 PM

I saw a Youtube with an interview with a couple of Vavoline petroleum engineers. One had commented that if you are doing an oil change oil that has been sitting around in the bottle a long time, you should shake it well first since the additives could separate out. Using that logic, it would seem that if the bus is sitting for a very long time with the oil in the sump, it could also separate out. Of course, it would seem that starting and running the engine would mix it all up again.

Dreadnought · September 27, 2016, 05:36:12 PM

Quote from: Iceni John on September 27, 2016, 12:59:29 PM
I was told that oil becomes acidic inside an engine, even when the engine's not running. Is this true? Also, do the additives slowly precipitate out if the oil sits undisturbed? These are just two things I've read, but who knows if there's any truth to them?

John

Hi, I don't see why it should. If it is left in the engine which is a sealed system- I don't see why the PH value should change. The only thing I can think of is-if condensation accumulates. If it were true then a sealed oil container of, say, Shell, should have a Best before date or recommended use by date.

For the oil additives to precipitate out the oil needs to be heated. While sitting- for the additives to 'fall out of suspension'- I've never seen this.