Ted Carbonaro Posted April 18, 2023 Share Posted April 18, 2023 Getting ready to flush and change coolant in my Onan Diesel 8000 HDKAK Manual says to use same coolant as my ISL400, 4.2 qts. Flush & change at 1000 hours or every 2 years. I’m just over 10000 hours, so ready to flush and refill. Looking for any tips, suggestions, DO’s or DON’Ts. Link to comment Share on other sites More sharing options...
Bill R Posted April 19, 2023 Share Posted April 19, 2023 @Ted Carbonaro Just did this on my 8K HDKAK. Pretty straight forward. You might want to also change the T-stat while you are at it. I also washed out the radiator fins. I did learn that you need to put the top cover back on if you start the generator. The cover needs to be on to force the air through the radiator. Here is a video from RV Geeks. 1 Link to comment Share on other sites More sharing options...
Ted Carbonaro Posted April 19, 2023 Author Share Posted April 19, 2023 Bill thanks for the video! It was very helpful! Like you said, straight forward but really good to watch someone else do it first. And thanks for the tip on the thermostat, I’ll definitely change it as well. Thanks! Ted Link to comment Share on other sites More sharing options...
vito.a Posted April 19, 2023 Share Posted April 19, 2023 Ted, do you really have ten thousand hours on your generator, or s that a typo? I just used Prestone antifreeze in the generator. The engines (Isuzu or Kubota depending on model) have dry sleeves that are not exposed to coolant. Be careful with the radiator drain plug, mine just screwed into plastic. Link to comment Share on other sites More sharing options...
Ted Carbonaro Posted April 19, 2023 Author Share Posted April 19, 2023 A typo it is. 1060 hours on it now. Just leaving Cummins with thermostat, gasket and coolant cap in hand. $62.12 + tax. Link to comment Share on other sites More sharing options...
J Goddard Posted April 19, 2023 Share Posted April 19, 2023 I'm also gearing up to flush & fill the cooling system on my 8K HDKAK. Seems like a good time to get this done. Also time to replace the coolant pressure cap and thermostat. Ted, which coolant cap did Cummins provide you? I just noticed that mine is marked 13 psi however the Onan Mobile Genset Operator's Manual states that the system is 14 psi. On further research, the Cummins part manual does call out part no. 0130-7902 which I believe is a 16 psi cap. Link to comment Share on other sites More sharing options...
Ted Carbonaro Posted April 20, 2023 Author Share Posted April 20, 2023 I haven’t opened the package yet, but I looked through the bag and I’m pretty sure it’s a 16 lb. I’m planning to do it tomorrow and I’ll let you know what Cummins gave me. Link to comment Share on other sites More sharing options...
birdshill123 Posted April 20, 2023 Share Posted April 20, 2023 I would check your genset manual. Yellow packaged Prestone is cheap junk. It does not hsve any of the diesel engine mfrs. approval numbers. I realize that a Onan is not the same as a hd diesel engine. But whoever built the engine in your Onan has a spec. 1 Link to comment Share on other sites More sharing options...
Gary 05 AMB DST Posted April 20, 2023 Share Posted April 20, 2023 What about using Cummins Compleat anti-freeze? Gary 05 AMB DST Link to comment Share on other sites More sharing options...
Tom Cherry Posted April 20, 2023 Share Posted April 20, 2023 I have changed my Genny coolant twice. I used the old fashioned HD coolant that was rated for the engine…the blah green. That was what ONAN tech support told me. look in your Camelot Owners Manual, it probably has a Texaco product (Monaco got a kickback). Look that up. There will be a spec for it. Then look at the Mobil precharged SCA heavy duty diesel engine coolant. That would be my choice. I totally trust and like the Mobil Delvac products for my Camelot. If the coolant is clean and pretty (green), then I would drop the coolant….let it drain totally. Then button it up and refill. Cummins did that the first time on the engine and Genny to keep my extended warranty in effect. They (shop manager at a large Cummins Coachcare) said that was what they did on the first and second changes. If you get the premixed (50 antifreeze/ 50 DISTILLED water), you make it easy. Flushing the totally draining and then refilling with Distilled water is a PITA and I don’t, from my industrial (Maintenance Management) and long term gear head that never let anyone change his oil until he was 63 YO old…. Otherwise but the concentrate and premix 50/50 with Distilled water and just refill and pass on the flushing… I know many folks have switched to the newer blends that are longer life and “permanent”, but using the specs that were required when our engines were built is OK if you change at some common sense intervals. Link to comment Share on other sites More sharing options...
96 EVO Posted April 20, 2023 Share Posted April 20, 2023 I just use the same HD diesel engine coolant I use in the Cummins. It's pre charged with SCA, which the gen engine doesn't need, but it doesn't harm anything! Link to comment Share on other sites More sharing options...
Gary 05 AMB DST Posted April 20, 2023 Share Posted April 20, 2023 Ben, is SCA the coolant additive that requires a filter? I am blank on SCA though I know I have heard about it. Gary 05 AMB DST Link to comment Share on other sites More sharing options...
96 EVO Posted April 20, 2023 Share Posted April 20, 2023 No filter required. Some of the older Cummins engines came with a coolant filter that had slow release SCA imbedded in the media. They did away with that filter completely, so on a wet sleeved engine, you add liquid SCA to your cooling system as needed. The Isuzu, or Kubota engines in these generators aren't wet sleeved, therefore, no SCA needed. Link to comment Share on other sites More sharing options...
Bill R Posted April 20, 2023 Share Posted April 20, 2023 X2 on using same coolant in engine and generator. Mainly to have only one jug of same coolant for top off if needed for either. I use the Compleat ES EG. Link to comment Share on other sites More sharing options...
Ted Carbonaro Posted April 20, 2023 Author Share Posted April 20, 2023 I’m running the Peak Final Charge Pro Series 50/50. Meets Cummins, Isuzu & Komatsu specs. #0130-7903 is the 16 lbs cap. Link to comment Share on other sites More sharing options...
Tom Cherry Posted April 20, 2023 Share Posted April 20, 2023 4 hours ago, Gary 05 AMB DST said: Ben, is SCA the coolant additive that requires a filter? I am blank on SCA though I know I have heard about it. Gary 05 AMB DST NO…as folks said, originally there was in maybe the late 90’s a SCA (Supplemental Coolant Additive?) filter that was like a time release pill…. Then, they switch to a SCA coolant. You SHOULD read up on it. Typically folks carry a small bottle of SCA or I do. When you test, annually, your coolant or have a qualified shop do that, you get an SCA reading and I usually add a few ounces annually. If the SCA gets low, then you will pit the wet sleeve (pictures I have seen looks like a carbide tipped Woody Woodpecker perforated the sleeve. NOT GOOD. I would tell you to MAKE sure the coolant test strips are NOT expired and not stored in a grungy hot area. Link to comment Share on other sites More sharing options...
Gary 05 AMB DST Posted April 22, 2023 Share Posted April 22, 2023 Got this from the Roadmaster plant manager in Elkhart, IN in 2008. After I bought my 05 Ambassador, I would make annual trips for the Ramblin'pushers rally in Goshen. I would go to the RV assembly plant tour twice a day to watch the assembly of the motorhomes to get knowledge of the construction of the MH. Same with the Roadmaster frame assembly plant but only one a day. In my 05 owner's manual, chart-filters & belts, it shows a coolant filter. I asked the plant manager where the filter was located. He looked in my manual and a 04 manual and they both showed the filter. He told me that the government rated the SCA filter as a hazardous material and it was removed from the engines in 2005. Since my 05 Amb was the first year for the 8 air bag suspension, as on the Endeaver, Holiday Rambler just took the 04 owner's manual and renamed it for the 05 Ambassador. Poor proof reading. Now the Fleetguard Compleat anti-freeze has an SCA additive in it and it is good for 150,000mi. At that point you should check the SCA level in the antifreeze and add the required amount. The antifreeze is good for 1,000,000 miles. Just my thoughts on replacing antifreeze. Gary 05 AMB DST 1 Link to comment Share on other sites More sharing options...
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