Viewing 15 posts - 1 through 15 (of 20 total)
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    • #3475
      MyPrevost
      Keymaster

      The coolant change project is progressing well, though it’s a major time investment. I’m transitioning from Power Cool, which requires SCAs, to an EC-1 spec extended life coolant. Although I’d prefer to use the Detroit Diesel extended life product, it’s only available in a 50/50 mix here in Knoxville, which doesn’t work for me. Instead, I’ll use CAT coolant, which is an OAT (Organic Acid Technology) and meets the industry standard. The pricing is reasonable: concentrate is $21.48 per gallon and pre-mix is $11.55.

      I assume the cooling system capacity of 24 gallons is accurate. Besides the engine, my system includes large volumes of coolant in the OTR heat exchangers, the Webasto, and the HW tank. I understand that draining the system completely would require significant disassembly, which I’m not prepared to do.

      Currently, I’m draining as much old coolant as possible through the petcock at the base of the radiator or the lowest coolant pipe. Each time, I drain about 15 gallons, leaving around 9 gallons in the system, including the piping, OTR system, HW tank heat exchanger, and transmission intercooler.

      To flush out the old Power Cool, I’ve drained and refilled with fresh water four times. At the last drain, the water was nearly clear with just a pink tinge. Since the EC-1 coolant can tolerate up to 10% SCA coolant, I’m planning to fill the system now, but first, I’ll flush the radiator and replace a couple of hoses on the Webasto system. After each drain, I run the Webasto, engine at high idle, and OTR heat system at the highest temperature setting to circulate the fresh water throughout the system.

      Replacing the hoses will remove more of the old coolant, so with the next fresh water fill, I’ll have nearly eliminated the old coolant. Each drain and refill have diluted the SCAs in the system, and theoretically, I should have about 2.4 gallons of old coolant mixed in by the time I flush the radiator.

      When I flush the radiator, I’ll isolate the bus engine from the rest of the system to avoid contaminating it with the flush chemicals. I plan to flush the radiator at least three or four times to ensure no chemicals remain. Assuming the system retains 9 gallons, I’ll add 9 gallons of concentrate for a 50/50 mix and then top off with 6 gallons of premix.

      I’m fortunate to have convenient waste disposal options in Knox County, TN, where I can drop off old coolant, oil, and other waste at no charge. I also have a suitable workspace where I can safely handle the coolant without risking spills or harm to animals.

      Overall, the project will cost around $270, and with any luck, I’ll only need to recharge the coolant every three years for the next six years. I’ll apply the same process to the generator soon, so I’ll only need to keep a gallon or two of concentrate on hand for both cooling systems.

      #3477
      MyPrevost
      Keymaster

      Wow, I thought I’d accomplished something major when I changed my fuel filters, oil, and oil filters this past weekend, and topped off the power coolant.

      #3478
      MyPrevost
      Keymaster

      Jon,

      Have you thought about using a regulated air supply to blow the Webasto and chassis heater lines free of coolant? Additionally, once you’re finished, it might be a good idea to drain a sample and have it tested by CAT to ensure the OAT is up to spec. I’ve heard that test strips are also available now.

      #3479
      MyPrevost
      Keymaster

      Between the remodel and all this, you’re really wearing me out… Are you aiming to reclaim that A1 status or what?

      #3480
      MyPrevost
      Keymaster

      Jon,

      Have you thought about using a regulated air supply to blow the Webasto and chassis heater lines free of coolant? Additionally, once you’re finished, it might be a good idea to drain a sample and have it tested by CAT to ensure the OAT is up to spec. I’ve heard that test strips are also available now.

      I considered several options, but one challenge with clearing both the Webasto and OTR coolant lines is that both have solenoid valves. If I disconnect the lines at the valves, I might end up with more issues related to burping and refilling the system. By the time I finish flushing the radiator, the affected portion of the system, and then re-open and flush the entire system again, I seriously doubt I’ll have much Power Cool left to worry about.

      The drained water now barely has a pink tinge, so I expect minimal contamination.

      I need to replace two short sections of hose in the supply and return lines for the forward Webasto units, which means they’ll be drained. I previously drained the system thoroughly and spent several hundred miles burping it, so I’m not looking forward to going through that process again just for the forward Webastos. I’m starting to feel a bit lazy.

      #3481
      MyPrevost
      Keymaster

      Jon,

      I recently used a vacuum fill tool while changing the coolant on my generator. It worked really well—no spills, air pockets, or overheating. When I pulled the vacuum, I discovered a small leak at my radiator drain petcock; if the vacuum doesn’t hold, there’s likely a leak somewhere. Once I had a good vacuum, I placed the fill tube in a bucket of premix and opened the fill valve. It was impressive to watch the fluid quickly get sucked into the coolant system.

      #3482
      MyPrevost
      Keymaster

      I have one of those tools and have used it quite a bit. I believe my plan will work well since I use the Webasto for a lot of the purging, as I’ve done before. Once the Webasto circulating pump starts running, I keep adding coolant to the header as needed. Then I run the engine until the thermostat opens. If it doesn’t get hot enough at high idle, I just back up my driveway a couple of times—it’s steep enough to put a significant load on the engine.

      Pulling a vacuum on the bus system takes forever.

      #3483
      MyPrevost
      Keymaster

      Jon,

      To warm up the engine and get the thermostat to open, you can safely apply the brakes, shift into Drive, and bring the revs up to 800-1000 rpm. Have you ever seen Prevost Car perform a stall test on a new transmission?

      #3484
      MyPrevost
      Keymaster

      You haven’t seen my driveway. Believe me. Two trips back up it and I’m done.

      #3485
      MyPrevost
      Keymaster

      I once watched Prevost Car perform a stall test on a newly installed Allison transmission. The technician applied the brakes, put it in drive, and ran the engine up against its governor, holding it there for what felt like an eternity. The transmission was grunting, the brakes were holding it back, and the engine was screaming—it was quite a sight.

      #3486
      MyPrevost
      Keymaster

      I changed my coolant before summer, drained the radiator, and used a light amount of compressed air to get an extra gallon or so out. I then filled it with fresh water and drove 5 miles at low speed. After draining and blowing out the system, I replaced the coolant with pre-mix. The water in Vegas is too caustic for good coolant (with a pH of 8.1 at my house).

      Back when I was an Iowa farm boy, we did all the equipment this way, but instead of fresh water, we used a mixture of water and a couple handfuls of Spic & Span. It worked well for getting the crud out of the equipment.

      I last changed my coolant about four years ago and have put around 115,000 miles on the bus since then. The coolant still looks good and has always tested fine with the strips.

      #3487
      MyPrevost
      Keymaster

      The coolant change is complete. I took extra precautions because I didn’t want to revisit the cooling system anytime soon. I replaced two coolant hoses that hadn’t been changed before, checked the entire system for potential leaks, and finalized the installation of the new extended life coolant.

      I drained and flushed the old coolant four times before using a cooling system cleaner. I used Cat 4C-4611, a fast-acting cleaner, adding 1 gallon to 15 gallons of capacity. I shut off all valves leading to the bus OTR and Webasto systems, isolated the engine and radiator, and ran the bus for 90 minutes at high idle, maintaining a steady 195 degrees.

      The water and cleaner drained out black. I flushed the system four more times, running the engine briefly each time, until the water was nearly clear. I then opened all valves to the coach systems, refilled with water, and ran the coach, OTR, and Webasto systems. After draining as much as possible, I added 12 gallons of EC-1 spec Caterpillar Extended Life Coolant and topped off with water. I ran the Webasto until it shut off to help burp the system and will recheck it tomorrow.

      In summary, the bus cooling system has been cleaned, all hoses are less than two years old (except for the engine hoses, which seem durable), and the old coolant and cleaner were thoroughly flushed out. The system drains about 15 to 17 gallons out of 24 if left to drain for a day. I don’t plan to open the system further, as the numerous drain and refill cycles should have minimized contamination.

      It was surprising how much draining and refilling was needed before the water ran clear, though it never achieved perfect clarity and always had a slight pink tinge. The dyes in coolants are evidently very strong. I was also shocked by how black the water was with the cleaner; despite regular coolant changes and filter maintenance, the cleaner loosened a lot of black crud. Caterpillar service techs use Calgon dishwashing soap if the system has engine oil contamination, but there’s no evidence of that in my system.

      #3488
      MyPrevost
      Keymaster

      Jon, just walking up your drive is a challenge in it’s self, not for the clogged artery crowd!

      #3489
      MyPrevost
      Keymaster

      I avoid walking up it. On the rare occasions, like when fetching the Sunday paper, I question my sanity when I’m about 50 feet from the top. It’s certainly a good way to warm up an engine, though.

      #3490
      MyPrevost
      Keymaster

      I avoid walking up it. On the rare occasions, like when fetching the Sunday paper, I question my sanity when I’m about 50 feet from the top. It’s certainly a good way to warm up an engine, though.

      Maneuvering the steep drive!

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