Cummins QSC 8.3 540 – Thermostat Replacement

[John]

Just doing research and didn’t easily come across any pics/threads on this process so figure I’d share some pics.  Probably none since it’s so easy but I took some pics.

Drain Coolant (Mine drained a tad over 8 gallons), (4) 10mm bolts, (arrow part) when taking off was under a tad bit of pressure as when second bolt came out the elbow sprung a tad.  When replacing, it was a bit of a hassle to get the second bolt back in as took some pressure to align it all and finger start the second bolt.

Circle is where the thermostat is.

Thermostat came with the green o-rings on each side of it.

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Rob Schepis

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[John]

Good job and appreciate the pics – Thanks Tony.  

What was the issue?  No issue but did this as part of sorting out another issue.  Engine temp creeping up at higher RPM (spun impeller hub thread).  Ultimately was a spun hub on impeller that caused temp issue but that motivated me to do HX and thermostat just to be sure there wasn’t something else going on.

Did the replacement fix all?  I don’t think the thermostat was an issue actually though but felt really good replacing it for peace of mind.

Bleeding the coolant system–did that go Ok?  Didn’t bleed per se.  Just filled as much as possible via cap (8.2 came out), low 7.x went back in and also filled up the overflow bottle.  Ran it to op temp for a bit (cruising, not in slip), overflow went empty and added maybe 1/2 gallon + back to HX and rest into overflow and all seems good.  Got the 8.2 back in +-.

J

[Tony Athens]

Good job and appreciate the pics.. 

 

What was the issue?  

 

Did the replacement fix all? 

 

Bleeding the coolant system–did that go Ok?

[Author]

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