Community Forums

Old Scout · 08-27-2022, 07:05 AM

Need help! I have owned my 2015 rig with a 600ISX for about a year. Assume" the current [red] coolant is the Rotella ELC, as indicated on the expansion tank label. Tested the coolant when I first got the rig--JG labs test showed no issues except nitrite level was a bit low [severity-2].
So now I am confused. Thought "red" indicated it was OAT coolant, but my local Cummins shop only sells "nitrite-free" OAT. Has the OAT formulation changed? If so, is the new nitrite-free OAT compatible with my older Rotella ELC? If not, what do I need to use to add coolant?

Old Scout · 08-27-2022, 11:53 AM

Think I have found the answer--although there are competing opinions on the internet. It appears OAT and nitrite OAT [or NOAT] are compatible. Some opinions suggest OAT, if added, will dilute the nitrite in NOAT. HOAT [hybrid OAT] is not compatible. So, my starting assumption that "red" is "red" isn't always true as there is no governing industry std for coolant color. Accordingly, you need to check product labels if you what to match coolant types.

c_oneil · 08-27-2022, 02:01 PM

Color is a tough way to tell much for sure. I am using Peak brand Fleetcharge coolant. It is a nitrite SCA precharged that is pink. Looking at it in different containers or light you might call it red. Here is an interesting chart from Cummins that shows Rottella ELC as sorta orange.

https://www.cumminsfiltration.com/so...es/LT36262.pdf

If someone previously mixed types based only on color it could be almost anything now.

Old Scout · 08-27-2022, 04:19 PM

Hey Carter, appreciate the feedback. The Cummins chart you provided is interesting--it implies that Rotella ELC [red] is an HOAT, and therefore only compatible with the Fleetguard EG Complete. That is if I am reading the chart correctly. But that goes against my grain to imagine that mixing red and blue coolants is a good thing. Guess I need to confirm whether Rotella ELC is an HOAT or NOAT. And even though the label on the expansion tank indicates Rotella ELC, and the JG Lab report indicates the sample I extracted has nitrite, I really don't know if the coolant is the OEM Rotella either--but suspect it is. Think I am back to the drawing board on this project....

IAlreadyGot1 · 08-28-2022, 10:52 AM

It appears that the coolant is available in both ELC and ELC NF (Nitrate Free) formulas.

Tank label indicates ELC.
Testing shows nitrates at less than ideal level.
Owners may says...???
Manufacturer says...???
Service records indicate...???

Good possibility that ELC with nitrates is what the machine needs.

Old Scout · 08-28-2022, 11:53 AM

Got1--think you are probably right. The rig is a 2015 model, which I have only owned for a year. No input available from previous owner and no maint. records after the sale thru a dealer. I was initially led to believe red was red with coolant--obviously not. Then I got frustrated when I couldn't seem to find Rotella ELC locally. Finally, I got concerned when internet research revealed concerns about mixing OAT/NOAT with ELC nitrite of HOAT coolants. Only issue now is knowing for sure what coolant is in my rig--is there a test/way to differentiate between ELC nitrate and HOAT, since both could be red?

IAlreadyGot1 · 08-28-2022, 03:42 PM

I don’t fancy myself as an expert on coolant. Given that you are not the original owner of a 7-8 year old coach and have no service records from the previous owner(s), the only way to truly know what coolant is in the system might be to drain, flush and replace it with a known product. Obviously, you’re trying to avoid that expense.

If it were mine, I’d contact Cummins, give them the information that you have and see what they can tell you about possible compatibility issues with the various OAT coolants. Cummins or JG Labs may be able to advise on methods to determine the current mixture of your coolant. I only noted that the test showed nitrites (not nitrates, as I misstated before) and the tank was labeled ELC, not ELC NF, as being indications that ELC, with nitrites, was probably used in the system from the manufacturer. There’s no telling what may have been added over the past 7-8 years.

Old Scout · 08-28-2022, 04:15 PM

Got1, that's a very good read. My past experience is with SCA-based coolants, which by now, I would have changed and moved on. Fact is I under-estimated the complexity of newer coolants and waited too late to solve this issue. Now I am coming up against a planned trip departure date. However, your advice is sound--time to flush and change out my "mystery" coolant.

Bruce Anthon · 08-28-2022, 08:24 PM

I spent two hours talking with a Cummins coolant engineer two years ago when I updated my 2003 ISL coolant. He explained the reasons for the various coolant types, the difficulty in updating fleet coolant specifications because of various engine models/manufacturers, seal compatibility, cavitation minimization etc. He recommended using Restore 2 flush and then using Fleetguard OAT (es complete). The restore did clean scale and deposits when flushing. I am very pleased with the choice of these products.

Alpine03 · 08-30-2022, 05:40 PM

I have a 2003 34FDDS with a 350ISC Engine do you know the coolant capacity.
It has the old green Fleetcool coolant thinking of changing it to Fleetguard ES Complete (OAT). I get an overflow from the surge tank so I installed an overflow tank to keep track of the overflow. I changed the cap to a 16lb but thinking of changing it to an 18 lb. I pressure tested the system to 15 lbs and it did not leak pressure after 1 hour.

IAlreadyGot1 · 08-30-2022, 06:20 PM

Quote:

Originally Posted by Alpine03

I have a 2003 34FDDS with a 350ISC Engine do you know the coolant capacity.
It has the old green Fleetcool coolant thinking of changing it to Fleetguard ES Complete (OAT). I get an overflow from the surge tank so I installed an overflow tank to keep track of the overflow. I changed the cap to a 16lb but thinking of changing it to an 18 lb. I pressure tested the system to 15 lbs and it did not leak pressure after 1 hour.

Capacity is about 10 gallons. Check level through the sight glass when engine is warm/hot. Filling to the sight glass when cold will lead to overfilling.

Changing to OAT will require a complete flush. Confirm with Cummins that OAT is suitable for your engine.

Bruce Anthon · 08-31-2022, 07:36 AM

Alpine03 you mentioned raising the cap holding pressure on your expansion tank. The posts earlier in this thread about maintaining the proper level of coolant is really key.
I had a slow dribble out of my overflow tube. It was just the coolant seeking its correct level. I added some additional site glasses to the expansion tank when I was replacing hoses, water pump tensioner, rhino coating the steel coolant tubes and coolant. Now as long as the coolant is above the second glass, I am good to go. Occasionally the fluid will reach the bottom of the top glass, but only when running really hard and in a 90 degree+ day. Nothing ever shows in the plastic catch tank.

This is the post on that modification.

https://www.irv2.com/forums/showthre...errerid=226483

Good luck on your update projects.

Alpine36 · 08-31-2022, 09:48 AM

Quote:

Originally Posted by Alpine03

I have a 2003 34FDDS with a 350ISC Engine do you know the coolant capacity.
It has the old green Fleetcool coolant thinking of changing it to Fleetguard ES Complete (OAT). I get an overflow from the surge tank so I installed an overflow tank to keep track of the overflow. I changed the cap to a 16lb but thinking of changing it to an 18 lb. I pressure tested the system to 15 lbs and it did not leak pressure after 1 hour.

Your capacity is closer to 12 gallons total, including the heater core and supply hoses. I flushed out all the green coolant and switched over to Fleetguard Complete EG. Buy six gallons of the concentrate (not the 50/50 blend) and six gallons of distilled water and you'll be good to go. Change the coolant filter to a non dca charged filter. 16 lb cap is correct. Do not overfill the expansion tank or it will puke it out. I installed a catch bottle in case it does, but it hasn't been an issue since learning the cold fill level. You want to just see coolant in the sight glass when warm, not cold.
Also, do yourself a favor and replace the expansion tank sight glass with one like this. Not sure this is the correct size, so do your homework before you order one. This is a absolute must do with the blue coolant, or you'll be chasing your tail.
https://www.raneystruckparts.com/fre...ent=Big%20Rigs