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CM570 Two new Thermostats stuck open - Printable Version

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CM570 Two new Thermostats stuck open - Finland25 - 02-01-2021

Hi. I have a 2002 cm570 and inframed it recently. They put a new coolant thermostat in it. I went to my first trip and after 700 miles my working temp drops from 175 to 120. I came back to shop and they replaced it with a new one. Now I I'm in the same situation again. 700 miles was 175 degree and now its sitting around 120 with 45 degree outside temp. My question is would it be a bad quality parts or dealer or shop do something wrong? Quick serve showing me a 4336659 for replacement 180 degree. Is anybody have an experience with Thermostats on this engine? Thanks for replying in advance.


RE: CM570 Two new Thermostats stuck open - 03maxpower - 02-01-2021

There is a footnote that they are missing and giving you the wrong thermostat. The one they are giving you is just a bit longer and when the housing is tightened down it’s forcing it to stay open.


RE: CM570 Two new Thermostats stuck open - smorgan87 - 02-01-2021

Are they replacing the press in seal when they replace the tstat? As mentioned above, are they putting the wrong one in there?


RE: CM570 Two new Thermostats stuck open - Finland25 - 02-01-2021

They replaced a seal with thermostat as well. Dealer gave them a thermostat by vin so a shop just installed what they gave them. Shop is so busy now with rebuilds and don't want to spend time on research. I trying to figure out by myself with quick serve but there so much superseded bulletins with lot of different part numbers so it so hard to understand which one is current and fit correctly


RE: CM570 Two new Thermostats stuck open - Finland25 - 02-01-2021

(02-01-2021 )03maxpower Wrote:  There is a footnote that they are missing and giving you the wrong thermostat. The one they are giving you is just a bit longer and when the housing is tightened down it’s forcing it to stay open.
Do you think it will stuck open right away or can work normal for 2 days and 700 miles then stuck? I think if it will be touching housing I'll be noticing it right away or it will be working weird but 2 days no problems at all then suddenly stuck.


RE: CM570 Two new Thermostats stuck open - 90petercar - 02-01-2021

Are you sure they didn't plug back in a sensor


RE: CM570 Two new Thermostats stuck open - Finland25 - 02-02-2021

(02-01-2021 )90petercar Wrote:  Are you sure they didn't plug back in a sensor

I checked both hoses from radiator. They was warm but not hot and didn't pressurized. So I'm assuming my gauge showing me a right temperature. I also open up a coolant tank to check if a coolant is hot or not right after the trip and coolant even don't expanded in a tank. Just warm about 100 degrees. So I think it's not a sensor and not a water pump because both hoses was warm and coolant flow exist.


RE: CM570 Two new Thermostats stuck open - Signature620 - 02-02-2021

Max power is probably on the money there. The spare parts people are usually used to selling the taller thermostat for EGR and newer engines.

Make sure they use 4336659 and not 4318947.


RE: CM570 Two new Thermostats stuck open - 03maxpower - 02-02-2021

Happened to me. Exact same thing. Call a Cummins shop and they will get you the right thermostat and you won’t have to worry about it.