[Archived]

NAPA filters should be fine. I always used Delvac 15-40 in the DD. Most any oil that meets the API spec should be fine, but Delvac is available almost anywhere, and it meets all the specs. There would be nothing wrong with Fleetgard filters either..whatever you want to do.

[DON]

Mark and I are 5000 mile advocates. For me the reason is simple. Prevost calls for a chassis lube at 6200 miles and I cannot track that on my odometer as easy as 5000 mile intervals so I figure as long as I am down under the coach I might as well change oil and filters.

While I use both Delvac and Rotella I have no way of knowing which is best. I use Baldwin filters mostly, but have used Detroit and Donelson also. Again, I have no way of knowing which is best.

But I do know one thing that absolutely amazed me. When I changed oil pan gasket this summer I expected to find some evidence of the silver gray sludge or film in the bottom of the oil pan. There was none. Not even a little, and while I want to suggest the 5000 mile oil and filter changes are the reason there might be another.

A while back my EGR seemed to not engage until my RPM hit 3200, and then turn off at 3400. At the same time there was a blockage in the system so no exhaust gases could leak past the EGR valve into the intake manifold. The change was subtle but as soon as that EGR defect occurred my oil started staying cleaner longer after an oil change. After a year or so my oil as viewed on the dipstick retained the nearly perfect gold color seen after a change for almost 2500 miles. It is my opinion the passage of exhaust gases back into the engine contributed to the black oil color soon after an oil change and the now obviously cleaner oil on the dipstick might also explain in part why there was zero sludge or film on the bottom of my oil pan.

But as regards choice of oil or filters it is my opinion that meet the spec for the engine will work. The engine shows 160,000 miles on the odometer, but there is no visible sign of dirt or sludge or wear anywhere.

[Pat & Jan]

Here’s my list of the various filters that will fit my DDC 60s:

Fleetguard# LF9620, LF3671, LF3620, Intl# 1885920C1, or Fram PH7405A, Donaldson Blue # DBL3998 or Donaldson standard level # P552100 or Donaldson mid level # P551016, Wix# 51971, Detroit# 23530573, Detroit Premium# DELF3998.

I use Fleetguard Venturi Combo # LF9620. This filter has a built-in bypass filtration system. Here’s a link: Fleetguard filtration link

Before Fleetguard started making this type filter, I would build and install a bypass filtration system on my previous coaches. Then Fleetguard started making these Venturi Combos for a few engines.

---

2025 Marathon H3 / 4th Prevost
21 Ram 1500 EcoDiesel 4x4

[Mark]

Always used NAPA – WIX on my 3 Marathons. If you handle the #1971 filter you find that it’s not a cheaply built part but a well made heavy duty part.

The $64,000 question on the Detroit Diesel branded filters is who builds it and too whose specifications.

Filter manufacturing companies bid on a contract to build the DD logo filter.

AL

[Dan]

Don, your comment on the bypass filter got me curious. I found this on the Donaldson site indicating that your DIY solution (primary + secondary) seems better.

TWO-STAGE FILTRATION A two-stage filter design attempts to combine the features of both a full flow and a by-pass filter. The two-in-one design significantly increases restriction, causing shorter filter life and decreased cold flow performance. Poor cold flow performance starves the engine of oil during start up, leaving the engine temporarily unprotected. This will lead to increased engine wear that may result in premature repairs or even engine replacement.

[Archived]

I have to ask: Why would Fleetguard, a division of Cummins, make filters that harm engines? And remember, Donaldson is a competitor to Fleetguard.

I been doing used oil analysis(UOA) for 10+ yrs on many kinds of our equipment. I’ve been running Fleetguard# LF9620 filters on our Prevost DD 60 series for the last 5+ yrs and 22k miles. I’ve done three UOA on it and all 3 show a clean bill of health.

IMO what Donaldson is saying may apply to something? but its obvious to me, not the DD 60s.

Just because its on the internet doesn’t make it true.

[Chip]

We often debate issues relative to our coaches and have the expertise to debate things like slides, OTR, roof airs vs Cruiseairs, rivets versus bonding, 4 stroke vs 2 stroke, etc.

What makes us experts is we literally have to live with certain choices of features.

We also have had discussions about topics we are less qualified to debate. Fuel treatment, oil type, and now filters. I have zero knowledge about filter technology but I do know Prevost and Detroit Diesel and Volvo do possess substantial knowledge. Whatever they call for in their maintenance manuals works for me.

I know Prevost owners want to maintain their coaches to a high standard and are willing to go beyond what is called for. My guess is all manufacturers of filters, oils, etc are going to create products that will not damage our coaches. We as owners likely do more damage due to extended periods of non-use than owners of fleets that are used frequently and for extended periods. I’ll bet the first few minutes of cranking and running an engine that has not been used for a long period grinds or wears away more metal than running the engine frequently does which makes a deep discussion about filters and oils somewhat invalid.

Don’t interpret my opinion about non-use as a suggestion to start the engine once a month. Every start after lubricants have drained down subjects an engine to wear and especially starts that do not end with the engine completely up to full operating temperature.

[Archived]

There are extreme scenarios I can think off that could lead to something like the Donaldson info suggests. Extreme scenarios would apply to any filter, full flow or bypass. Overwhelmed with crud/debris and bad things could happen.

A full flow filter is a compromise between flow volume and filtering efficiency. Too small a micro rating and the flow is inadequate. Too large a micro rating and filtering efficiency is inadequate.

A filters efficiency increases as its porous media clogs up.

I learned early on in my pilot career, 40 yrs ago, about cutting open oil filters to see what’s going on. So that’s what I do. There has never been much of anything in any of our MH filters.

I believe Jon is spot on. Sitting idle is NOT good for our beasts.

My high compression race engines sit idle sometimes for months at a time. When its finally time to go race, I’ll crank it over with the ignition off until I see oil pressure, then let er rip tater chip. Anybody know of a way to do this on the bus?

How many piston aircraft plots were taught to hand prop their bird? This way the engine got “oil primed” a little, plus you could feel if there was a dead cylinder, and if it was a round engine, the oil was removed from the lower cylinders to prevent hydraulic lock. Ahhhh the good ole days.

Oh I forgot, NAPA filters are fine.