Onan 7500QD Coolant

[dennis.mcdonaugh]

The manual says drain, flush and replace coolant every two years - that seems a little excessive to me. When I bought the MH in 2016, I changed the coolant with Prestone and the label said it was good for 3 year so I went with that. I changed it again in 2019 and used Peak this time which had a label that said it was good for 5 years. So 5 years later, I just replaced it again with Prestone, but now the label says its long life and good for 10 years. What's everyone else doing about the change interval on their generator coolant?

[96 EVO]

6 years.

[Bill R]

I sample every two years.  Not only does this give you the current condition of the coolant, but a trend over time to determine when it is getting close to do a coolant change.  JG Lubricants or Blackstone Labs are commonly used.   

[David Pratt]

Cummins recommends the Shell Roetella ELC in its engine and generators. Foretravel installs it in all thier Coaches and is in my ISX and Generator.

I have attached the information below.

 

Shell Rotella ELC Nitrite Free Pre-Diluted  50/50 Premium, Nitrite Free, Extended Life Antifreeze/Coolant for Commercial and Mixed Fleet Use

Shell Rotella® ELC Nitrite Free (NF) Pre-Diluted 50/50 antifreeze/coolant is based on proven Shell Rotella® ELC OAT technology for extended life operation up to 600,000 miles/12,000 hours in medium and heavy duty diesel, gasoline, and natural gas vehicles and up to 150,000 miles in passenger cars and light duty trucks. Nitrite free formulation provides improved protection of aluminum components in modem engines including brazed aluminium heat exchangers and meets many of the newest OEM specifications. Shell Rotella ELC NF Pre-Diluted 50/50 is pre-diluted and ready to use. It requires no further dilution.

•             All Climate Use

Shell Rotella® ELC NF Pre-Diluted 50/50 provides protection against freezing at low temperatures and boil-over protection at high temperatures during summer months and/or severe operating conditions at proper dilutions. As sold, Shell Rotella® ELC NF Pre-Diluted 50/50 provides freeze protection down to -34°F / -36°C and boilover protection up to +265°F I +129°C (with the use of a 103.4 kPa pressure cap). No further dilution is recommended.

•             Extended Life Capability

Shell Rotella® ELC NF Pre-Diluted 50/50 typically provides up to 600,000 miles (1 million km) or 12,000 hours in commercial applications under normal operating conditions without the use of Extender or SCAs, or up to 150,00miles (240,000 km) service intervals in passenger car service provided the coolant is frequently checked and kept in good condition.

Shell Rotella® ELC NF Pre-Diluted 50/50 helps provide much longer water pump seal life than conventional coolants due to the absence of abrasive dissolved solids. The product also provides cavitation protection to help prevent erosion corrosion wear.

•             No SCA Use Required

No supplemental coolant additive (SCA) use is needed during the life of the coolant.

•             Excellent Cavitation (Pitting) Protection

Formulation delivers a high level of protection against cylinder liner pitting due to cavitation.

•             Excellent Corrosion Protection

•             No SCA Use Required

No supplemental coolant additive (SCA) use is needed during the life of the coolant.

•             Excellent Cavitation (Pitting) Protection

Formulation delivers a high level of protection against cylinder liner pitting due to cavitation.

•             Excellent Corrosion Protection

Heavy duty, mixed application antifreeze I coolant

Shell Rotella® ELC NF is designed for commercial and passenger car engines operating on diesel, gasoline, natural gas, propane, LPG or methane based waste gas.

[dennis.mcdonaugh]

That’s not the recommended coolant for my 24 year old Onan generator. Nothing wrong with it, but most of our generators are not wet sleeve design and don’t require SCAs in regular coolant or an OAT coolant. 
 

[96 EVO]

4 minutes ago, dennis.mcdonaugh said:

That’s not the recommended coolant for my 24 year old Onan generator. Nothing wrong with it, but most of our generators are not wet sleeve design and don’t require SCAs in regular coolant or an OAT coolant. 
 

No, but your Cummins engine probably is wet sleeved, and most only want to carry one type of spare coolant.

[dennis.mcdonaugh]

1 hour ago, 96 EVO said:

No, but your Cummins engine probably is wet sleeved, and most only want to carry one type of spare coolant.

I've been running Peak OAT coolant in the coach since about 2008 and continue to run regular coolant, Prestone this time, in the generator. Carrying the left over quart of Prestone antifreeze doesn't seem as big a deal as the procedure you have to go through to change to OAT coolant in the generator.

[David Pratt]

Dennis, At our last gathering in Tampa 2023, the Cummins Rep explained the changes and recommendations for coolant in the Cummins engines.

Take a moment and go to;

https://shop.sclubricants.com/pub/media/pds/shell/Shell-Rotella-ELC-Nitrite-Free-Pre-Diluted-50_50-datasheet.pdf

and read the Technical Data Sheet on the Rotella ELC coolant and it should answer any questions you might have. It states that it is compatible with most coolants and  all types of engines.

[wamcneil]

On 3/25/2024 at 6:10 PM, dennis.mcdonaugh said:

I've been running Peak OAT coolant in the coach since about 2008 and continue to run regular coolant, Prestone this time, in the generator. Carrying the left over quart of Prestone antifreeze doesn't seem as big a deal as the procedure you have to go through to change to OAT coolant in the generator.

The “procedure” is basically drain and refill. My OCD requires a flush with distilled water also, but Cummins say’s that is not necessary. 
You asked what everyone else is doing… and I think a lot of us use an extended life HD coolant that is much better than what is spec’d for the generator, and then pretty much never change it again. 
If you want to continue to use conventional coolant, probably best to follow the maintenance schedule for conventional coolant. 
W