Cummins 8.9 ISL 400/1200. What do you guys consider to hot for coolant temps.

onanysunday

onanysunday

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So we drove this coach back after buying it almost 900 miles. After reading online it sounded to me like 225 was the max temp that a lot of people don't like to go over. Right in the middle of summer and temperatures above 100 on some of the hills I was getting it up to 220. Of course gearing down and keeping the RPMs up. Just talked to a friend of the family that owns a diesel repair shop. He thinks 220 is still a little hot for that motor. Side radiator and it did have some dirt in it that I have rinsed out but it wasn't real bad. If I remember right the dash light for coolant temp comes on around I think 210 or 215. Don't remember exactly. This is a country coach and did come with the upgraded and engine monitoring system with a bunch of sensors. So I'm assuming the engine temp is correct. Certainly seems to be a little more accurate than the factory gauge on the dash.
 

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This thing did have a straight pipe on it and was a little too noisy for me. So I put a straight through muffler on it a little bigger than the aero 4040 XL. That was going to be my choice but sounded like it might still be too noisy. We will see how this does and I'm not sure if it will change the coolant temperature when running.
 

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IMO that rig should hold 180 all day long. Pulling a grade with a trailer may see 190-195 but come down quick once leveled out. Does this have a tuner on it? Do you have an exhaust temp gauge?
 
Grease Monkey said:
IMO that rig should hold 180 all day long. Pulling a grade with a trailer may see 190-195 but come down quick once leveled out. Does this have a tuner on it? Do you have an exhaust temp gauge?
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No tuner all stock. No exhaust temp gauge either
 
The hitch is rated at 10,000 but in the country Coach manual they only say it Max of 7,000. I know this coach has pulled a lot more weight than that. For me I will either be flat towing a crew cab Chevy truck. Loaded with crap it might be $5,500 lb. And my sand rail on the open trailer max weight maybe $5,500 to 6,000 lb
 
Id be curious what thermostat is in this engine. Do you have the engine serial number handy
 
Grease Monkey said:
IMO that rig should hold 180 all day long. Pulling a grade with a trailer may see 190-195 but come down quick once leveled out. Does this have a tuner on it? Do you have an exhaust temp gauge?
Click to expand...
Well your comment asking about the engine numbers made me think why don't I just call cummins. Answered their phone within 2 minutes. Guy was really helpful. He looked up my engine and said that thermostat opens at 203°. He said he would not go over 225 with that motor. He did talk about how fast the motor cools down once you get done with your climb and this thing cools off very quickly just like it should. So I think it's all good. I will rinse that radiator out one more time since I can see a little bit more debris at the bottom of the fins. I was also thinking about a pyrometer to check egts before I even posted this. He said not really necessary.
 
Did you buy this from a union member in St. Anthony? If so it could be overloaded with Keystones in every storage compartment and cabinet... 🤣 🤣
 
AlpineFunco said:
Did you buy this from a union member in St. Anthony? If so it could be overloaded with Keystones in every storage compartment and cabinet... 🤣 🤣
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Yep :p Still looking for those Keystones. I was robbed.
 
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