(01-03-2018 )DDlighttruck Wrote:  '03 ISX CM870. Low coolant level CEL.

I flushed the coolant four times around May 2017. First three times with simple green as a cleaner, then the last time with Cummins coolant flush cleaner. There was oil in the coolant from the original engine that was replaced. The original coolant level sensor worked if you cleaned it and put it back in. I've been running green coolant since then.

The original sensor was replaced around the same time I did an EGR tune-up, maybe June or July. I had one coolant hose blow in the summer, and one heater hose blow in the fall. So I've kinda lived with the CEL, in my opinion it seems to take a while to burp, and adding coolant was just part of life.

I wasn't adding coolant for a month or two. Life was good, except the CEL. Used a multimeter on the sensor, according to Insite my sensor was outside the ohm range listed for a good sensor, cleaned it and put it back in. Ordered a new sensor, about a week went by until I could get the new sensor, CEL was back on. Changed the sensor 2-3 weeks ago, good up until last weekend when the CEL came back. Popped the hood it's showing coolant is still full.

Do I flush it completely again and start running red coolant, now that I think the leaks are fixed? I read that the red coolant is better, regardless.

Do I change the sensor again, or look at possibly wiring issues? Maybe pop the original one back in?

I just don't get this, it should be a simple fix......

(01-04-2018 )Hammerhead Wrote:  

(01-03-2018 )DDlighttruck Wrote:  '03 ISX CM870. Low coolant level CEL.

I flushed the coolant four times around May 2017. First three times with simple green as a cleaner, then the last time with Cummins coolant flush cleaner. There was oil in the coolant from the original engine that was replaced. The original coolant level sensor worked if you cleaned it and put it back in. I've been running green coolant since then.

The original sensor was replaced around the same time I did an EGR tune-up, maybe June or July. I had one coolant hose blow in the summer, and one heater hose blow in the fall. So I've kinda lived with the CEL, in my opinion it seems to take a while to burp, and adding coolant was just part of life.

I wasn't adding coolant for a month or two. Life was good, except the CEL. Used a multimeter on the sensor, according to Insite my sensor was outside the ohm range listed for a good sensor, cleaned it and put it back in. Ordered a new sensor, about a week went by until I could get the new sensor, CEL was back on. Changed the sensor 2-3 weeks ago, good up until last weekend when the CEL came back. Popped the hood it's showing coolant is still full.

Do I flush it completely again and start running red coolant, now that I think the leaks are fixed? I read that the red coolant is better, regardless.

Do I change the sensor again, or look at possibly wiring issues? Maybe pop the original one back in?

I just don't get this, it should be a simple fix......

Was the sensor you purchased as a replacement an OEM or after market one DD?

Green coolant is fine to run, just make sure you have test strips and check it at a maximum quarterly (suggest monthly) as the chemical balance its quite as stable as red.
I have been told that green is a little thicker than red, so it is less prone to weeping and cold leaks which in the Canadian climate without a shop may be nice. As well as shutting the truck off and running Webasto/Epar in the winter, wanna find a cold leak, this will make you.
This is the first truck I've ran red in, because that's what it came with, but I've never had any specific issues with green as long as I kept up on the test strips and added chem's as req'd.