Hi, I have a 2013 Peterbilt 579 with a Cummins ISX 15 550hp. Last week while stuck in traffic low coolant warning light came on along with the engine with a wrench. Stopped on the side and coolant was coming out of the over flow hose. Engine is at normal tempreture and the Load weight was about 7000 lbs. took it to a local mechanic did a pressure test found nothing. Thru out the week when I stop at a shipper for 5 mins the low coolant warning comes on and the water in the reservoir tank goes below the Max full line to under the sensor. If I turn it off the coolant level rises back up to the fill line. If I release the cap a little and pressure gets out the coolant comes back to normal. I unscrewed the relief valve on the pipe under the radiator in hopes to relief air? Still same problem I placed the relief hose in a bottle To check for bubbles, NO bubbles. What could be wrong? Thank you all for your time.
Just had this issue on a 2015 with an MX 13. Ended up tearing the head off and finding the head was cracked between valves on the #4 cylinder. Same issue are yours. No bubbles but when running would push coolant out of the overflow. Change your pressure cap first though. They have a pretty high fail rate and if they wont hold 7-8 psi it will allow coolant to pass
Check the EGR cooler make sure it's not eating the coolant and exhaust gases can get pushed into the reservoir causing excessive pressure. CM2250 ISX also have liner protrusion problem and specifically cylinder 4 and 5 and that can cause the head gasket the blow and put exhaust gases in the cooling system. You can test your reservoir with this and it will indicate if there is exhaust gases inside the coolant or not: https://www.amazon.com/Block-Tester...t=&hvlocphy=9031140&hvtargid=pla-570352767565
Took the words right out of my mouth! My bet dropped liner. Check EGR cooler first though. Sometimes it will show itself bad by pooling up coolant on top of the transmission because it will leak at the tube wrapping around back of engine. You can get a clear look from passenger side of engine with a flashlight.
I had same problem twice on my 06 volvo with a Cummins ISX. Both times was a cracked head due to liner protrusion.
Dollars to doughnuts your engine dropped a liner. Cummins have an issue with the higher HP engine doing this. My 2013 389 with an ISX 600 started having a low coolant alarm and puking coolant. Pressure tested at a TA service center held 13 psi to 15mins at which time I replaced the PSI cap. It was still puking coolant at high boost PSI levels (over 15psi) after about 1k more miles I took it in and it ended up having a dropped liner making the head gasket leak and pressurizing the coolant system. This is a very very common problem around the 500K mark on higher HP ISX's. The first test is to check for exhaust gas in the coolant it's cheap and quick. 2nd test is to physically look at the EGR cooler inlet and outlet's Contact a few shops and ask about the ISX liner problems you will be surprised.
