Community Forums

Rusty Kramer · 07-09-2022, 10:06 PM

I just purchased a coach with an ISL 400 Cummins. It was very well cared for but the original owner has passed so I am lacking some information.

Is there a way to tell what Type of coolant is in the system? I am trying to determine if it is an OAT type or If I need to check SCA levels.

There are some service records I just have not found any info on this yet.

I might check with Blackstone labs to see if they can test a sample.
thanks for any info.

TB673 · 07-09-2022, 10:12 PM

Quote:

Originally Posted by Rusty Kramer

I just purchased a coach with an ISL 400 Cummins. It was very well cared for but the original owner has passed so I am lacking some information.

Is there a way to tell what Type of coolant is in the system? I am trying to determine if it is an OAT type or If I need to check SCA levels.

There are some service records I just have not found any info on this yet.

I might check with Blackstone labs to see if they can test a sample.
thanks for any info.

Is there a reason that you haven't contacted a Cummins Dealer?

Tim

Dutch Star Don · 07-09-2022, 10:28 PM

I think the best way is to just pull a sample. They should be able to tell you what type of coolant and the condition both it and the motor are in.

153stars · 07-10-2022, 02:57 AM

If its green pretty good chance you need to test with strips, I know not green is 100% non OAT better than 50/50 . Test with strips for nitrate and moly levels they are cheap by 3 pack. Check coolant filter if a blank/ non sca has been put in. Look for label stating OAT has been added near coolant tank.

Bruce Anthon · 07-10-2022, 08:35 AM

When your coach was built, OAT was not commonly used in new vehicles. My 2003 ISL had conventional antifreeze. I know you said it was well maintained, but I would suggest you change all the fluids and filters to give you a new base line starting out. Engine, coolant and transmission (there is a new spec. for synthetic trans fluid that you should included in your upgrade -T668). As mentioned earlier, the water filter should be a filter only, no additives version, if it has had OAT or you ae switching to it.

wolfe10 · 07-10-2022, 08:48 AM

When I buy a coach at that age with (16 years old)no/sketchy records, I ASSUME that all fluids need to be changed and do it.

That way I have absolute knowledge that a low-cost fluid change will not cause expensive damage or leave me on the side of the road.

And, even the long-life coolants are basically 6 year coolants. I would flush and fill with one of the new generation OAT based Fleetguard products since you have the Cummins engine and Fleetguard is Cummins's in-house brand.

If you are referring to a short-term "top off", just use distilled water.

znt1186 · 07-10-2022, 08:56 AM

Agree with Wolfe10. New to me coach, the first top is to a qualified shop to change all fluids, belts, etc. and do a complete check of everything. More or less starting with a clean slate. I keep maintenance records from then until.....

Surf Fisher · 07-10-2022, 09:03 AM

Blackstone does not offer coolant analysis, but JG Lubricant does.

If it's green, chances are that it is the old style EG coolant. If it's some other color then it may be OAT or not.

Rusty Kramer · 07-10-2022, 09:34 AM

Thanks to all. Yes I am in the process of ordering all filters and I will change everything. I may bring it to a shop for the coolant. That is the only fluid I have not ever done.
I think I will send a sample to JG.

Thanks to everyone.....

RK

Country Road · 07-10-2022, 10:31 AM

Quote:

Originally Posted by Dutch Star Don

I think the best way is to just pull a sample. They should be able to tell you what type of coolant and the condition both it and the motor are in.

You are correct if you want to find out exactly what’s in the cooling system.

The problem I have with that is with an older vehicle where you aren’t the original owner, there’s no telling what someone used in the system.

The safest way would be to do an engine cooling system flush and reinstall anti freeze according to the engine manufacturer’s specs. Just my thoughts.

Mudfrog · 07-10-2022, 03:38 PM

Quote:

Originally Posted by Country Road

You are correct if you want to find out exactly what’s in the cooling system.

The problem I have with that is with an older vehicle where you aren’t the original owner, there’s no telling what someone used in the system.

The safest way would be to do an engine cooling system flush and reinstall anti freeze according to the engine manufacturer’s specs. Just my thoughts.

Thank you! Was wondering why that had not been mentioned yet.

Am I being naive in thinking it shouldn't be that difficult to find the info in a service manual for that particular year and engine? Posting the chassis year on here might help to narrow this down.

Winemaker2 · 07-10-2022, 06:55 PM

I would not rely on Cummins recommendations alone.
Check with Chassis mfg as they are the ones that put the cooling system together. When I was trying to confirm what coolant to use in my Freightliner w Cummins ISB engine FL had a very different recommendation than Cummins due to the sensors they installed in the system.

Rusty Kramer · 07-10-2022, 09:42 PM

Thanks, I am going to try to check with the strips. I plan to flush the system.

The Monaco Roadmaster chassis was built by the Monaco Coach company in Oregon back in the day.

Mudfrog · 07-10-2022, 10:08 PM

I don't know much about diesel maintenance but I am trying to learn a bit and maybe help while I'm at it. This old thread may or may not be helpful.

Coolant-change-isl-400