Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > POWER TRAIN GARAGE FORUMS > Cummins Engines
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 08-12-2022, 07:49 PM   #1
Senior Member
Doug427's Avatar

Join Date: Dec 2019
Location: Houston, TX
Posts: 1,034
Cummins ISL400 oil capacity question

I figured I would go right to the source, in this case Cummins, to ask about oil capacity of my engine. I called numerous times, after spending a cumulative 90+ minutes on hold I gave up. I tried their chat and got an agent, who through chat really didn't seem that sure of himself. I gave him my engine serial number, which is a 2005 ISL 400, ser. number 46448341. He says the engine holds 28 quarts total, and he's insistent that the oil filter holds 4 quarts just in the filter. That's 28 quarts total with 4 included in the filter. That seems high to me, the filter seems way too small to hold a full gallon. Anyone have another resource to check on total capacity including filter? I used to have my repair shop change the oil with synthetic. His shop rate is now up to $190 per hour, and the charge for a complete oil lube and generator service is approaching $1K. That's crazy, I can easily do it myself.

I'm thinking about going to conventional oil. We only drive 3000 to 5000 miles a year, and I always end up dropping perfectly good synthetic oil out long before its mileage limits due to the year passing. Rotella T4 in a 15w40 weight here in the Houston heat should do just fine. We don't use the rig in cooler weather.

I'm hoping when I get under there I find that the oil pan has an upper and lower plug so that I have a way to efficiently handle that large a quantity of oil. Any thoughts you guys might have on any of this would be very welcome. I do my cars all the time, it's time I start doing the oil changes and fuel filter changes on my RV engine and gen as well.

2005 Newmar Mountain Aire 4304 - 4 slides
2011 Jeep Liberty 4X4 towed
Doug427 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free! RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-12-2022, 08:27 PM   #2
Senior Member
Join Date: Jan 2020
Posts: 465
A vacume pump for the oil can be used on most things, and its a very controlled drain, then you can pull the plug to get the rest out. Sucking it out would give you a good idea of what is the amount.
The one i have can suck and evac liquids. Just put hose in oil dip stick tube and pump up, and walk away, and repump as needed, wile doing the filter.
They arent very expensive and would make the gen easy also.
A fumo type or other controlled drain plug can be put in after the drain plug is removed to make the next one/s easy and controlled. I would think one could be put on the gen also. One with a tip to put a hose on can easy direct to containers, shutting off between filling a container. Used laundry jugs work for me.
I put one on my truck, as it takes 3 gallons of oil, and makes changes very controlled to fill containers to go to a collection place or a shop that burns it for heat.
A shop manual for your rig should have all the info you may need, for capacities and grease points, as well as intervals.
The best place is the next place.
travelorer99 is offline   Reply With Quote
Old 08-12-2022, 08:57 PM   #3
Senior Member
Holiday Rambler Owners Club
Join Date: Apr 2020
Location: Farmington Hills, Michigan
Posts: 580
My 2003 built ISL 400 is the same, holds 7 gallons total (~1 gal in the filter).
But you can check by e-mailing with your engine serial #. I got a prompt reply couple years ago.

I don't waste money on synthetic. Or shops on anything that I can do myself. I use Rotella T4 15w40 and change the oil every year.
Last summer I replaced the oil plug with Fumoto oil drain valve. Should make it easy to drain directly to the old 1 gal jugs. After my current trip I'll be changing the oil and see how it works.
2004 Holiday Rambler Imperial 40PKD, Cummins ISL 400
2019 Buick Envision AWD
Lowflyer1 is online now   Reply With Quote
Old 08-14-2022, 04:17 AM   #4
Senior Member
Holiday Rambler Owners Club
Join Date: Apr 2020
Location: Farmington Hills, Michigan
Posts: 580
Follow-up on the Fumoto oil drain valve. It made the oil change the easiest & cleanest I've ever had in any vehicle, direct to old 1 gal jugs.... except the sheer volume of oil and the big filter.
I had purchased a piece of tubing ahead of time to fit snugly on the Fumoto outlet and cut that to proper length to reach into the empty containers.
That also makes it easy to take the oil sample.
2004 Holiday Rambler Imperial 40PKD, Cummins ISL 400
2019 Buick Envision AWD
Lowflyer1 is online now   Reply With Quote
Old 08-20-2022, 10:47 AM   #5
Senior Member
96 Wideglide's Avatar
Holiday Rambler Owners Club
Join Date: Aug 2010
Posts: 9,016
Mine gets 24L which equals 25.36 US quarts.

That puts my level on the dipstick just a bit below the full line.
Ben & Sharon
2008 43' Holiday Rambler Scepter PDQ
96 Wideglide is offline   Reply With Quote
Old 08-20-2022, 04:27 PM   #6
Senior Member

Join Date: Feb 2020
Location: NY State
Posts: 1,880
27.5 qts with filter in our 2005 ISL (which is installed in our 2006 coach because Tiffin buys ahead).
1976 Southwind 28', '96 Winnie 34WK,
2006 Tiffin Allegro Bus 40QDP
n2zon is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cummins ISL400 won't start.... Gary Wittig Cummins Engines 3 07-31-2021 12:56 PM
Oil drain plug ISL400/8.9L Playtime III Cummins Engines 19 11-03-2018 11:07 PM
2004 Dynasty Oil pan change out? ISL400 Burgy Cummins Engines 6 05-09-2016 08:21 AM
Cummins ISL370 to ISL400 Smitty77 Cummins Engines 5 04-01-2015 10:13 PM
08 KSDP MM ISL400 Cummins Questions glemo81540 Newmar Owner's Forum 3 04-02-2013 05:23 AM

» Featured Campgrounds

Reviews provided by

All times are GMT -6. The time now is 06:25 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.