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chet_h · 06-21-2022, 06:03 PM

I'm looking to flush the cooling system on my 2001 HR Septer pbd 40 with the 8.3 ISC. Any suggestions on where to look for the cooling system capacity? I'm apparently looking in all the wrong places!

Thanks in advance!

theroc · 06-21-2022, 06:58 PM

You know, the 2001 Scepter owner's manual is one of the more comprehensive that I've seen as it pertains to the chassis. It gives good general information on the cooling system maintenance but I don't see any capacities listed for the cooling system itself. They seem to list capacities for some of the other fluids, however.

Go to pages 10.265 to 10.267 for the cooling system maintenance.

If you don't have it, here is the PDF:

2001 Holiday Rambler Scepter owners manual

It does give the coolant filter part number, however, on page 10.286

If you go to this thread, the OP has an Endeavor that I'm going to assume has the same engine on the same chassis as you do and he says 11 gallons.

2001 Cummins ISC 330 coolant change

(if you don't get confirmation from somebody more in the know, we may want to ask a moderator to move this thread to the Monaco Owner's Forum)

Dutch Star Don · 06-21-2022, 07:15 PM

Since it looks like you'll need right around 11 gallons, here is a good way to do it. Buy two gallons of coolant concentrate. Add both and then fill the rest with 50/50 mix. This way, the two gallons of concentrate will account for water left in the system.

When I changed the coolant out on my 2005 Cummins ISL, I used Organic Acid Technology (OAT) coolant. It actually ran cooler and doesn't require testing. I used Final Charge.

chet_h · 06-21-2022, 07:20 PM

Thanks for the links. I have download (and read) the owners manual specifically the pages you have kindly noted. I've tried to do my homework but to no avail. You would think this information would be easily found in the owners doc's. I may just have to plan on 12 gallons and see what the end result is. Sometimes my ocd gets in the way! LOL

chet_h · 06-21-2022, 07:49 PM

Thanks Don. I like the creative approach with the concentrate and the 50/50. I will go with that. I have to admit I was on the fence with the (oat) coolant. But the more I read it just doesn't make much sense to use anything else since I'll be doing full blown system flush.

NCC-1701A · 06-29-2022, 02:32 PM

Regarding testing.......

I switched to OAT in the Spring of 2020. I used Fleetguard. Flushed with a Fleetguard cleaner, then twice more with distilled water, then put the coolant in.

That fall, with around 5000 miles on the new coolant, I sent in a sample as I do every year. Came back 75 ppm aluminum (way into the red zone) and prior tests were ZERO ppm. The lab retested the sample to be sure. The testing lab said they frequently see this when first changing older systems to OAT as it is actually a very good cleaning agent and will work to scrub out any built up deposits from the cooling system (apparently better than Fleetguard Restore cleaner). So I drained again, flushed once, and put in new OAT which I ran around 5000 miles in 2021. Last fall's sample was a trace of aluminum.

Based on my experience and what the testing lab told me, my recommendation is to spend a few bucks on a coolant sample test when converting an "older" system from a conventional diesel coolant to OAT. Run for several thousand miles and sample just to be sure the new coolant isn't contaminated.