Engine temp

[Sagdito]

While motoring around today noticed my starboard engine temp would drop to 170c if I dropped revs below 1600rpm while port engine would stay at 180c this is the first time I have noticed this. I would have thought the thermostat should keep temp at 180c so does this mean that its faulty. Cummins 6BT 5.9s
Any ideas.
Phil.

 

[rwidman]

Thermostats can and do fail. In your case, you could swap the two from engine to engine to determine if that's the problem.

 

[Baker]

I would not worry about it one single bit. As long as the engine is remaining cool enough during normal operation, there is nothing to worry about. Also, if you are really worried, the first thing to do would be to to get a laser temp gun and see if the gauge is reading correctly.
Finally, thermostats on a Cummins are a pain in the ass. You gotta take off half of the front of the engine to get to it.

 

[Art]

I always feel temp gauges are just approximations; hopefully close ones. Can't always be trusted. Good quality laser temp gun is my fall back preference. Only takes a few seconds to hit all sections of an engine for getting well rounded temp check on all engine portions.

 

[Ski in NC]

Lots of engines, really most, temp drops when going from loaded to light load. 10F swing is nothing to worry about. 170 is fine. 180 is fine. If it dropped to 130F I'd be putting in a fresh Tstat.

 

[Sagdito]

Thanks guys will keep my eye on it, as Baker said I believe they are a PIA to change.
Phil.

 

[markpierce]

Just replace both thermostats at the next engine-maintenance cycle, and hopefully be done with it. If it's a pain to do yourself, hire a professional and support a local worker.

 

[Lou_tribal]

On my engine the temp gauge is marked like 50 - 85 - 110 (in C).
I would not even notice plus or minus 10 degres.
Just the raw water temp variation from summer to fall could result in a plus or minus 10.

L.

 

[sunchaser]

While motoring around today noticed my starboard engine temp would drop to 170c if I dropped revs below 1600rpm while port engine would stay at 180c this is the first time I have noticed this. I would have thought the thermostat should keep temp at 180c so does this mean that its faulty. Cummins 6BT 5.9s
Any ideas.
Phil.

As noted by others, a 10 F drop is not a current big deal. But, a 10 C drop may be. Do you mean F or C?

 

[RT Firefly]

Greetings,
Mr. s. I believe Australia uses the metric system.

 

[roguewave]

Finally, thermostats on a Cummins are a pain in the ass. You gotta take off half of the front of the engine to get to it.

Yes they are, I did mine...not difficult but a PITA

 

[Sagdito]

Gauges in Fahrenheit so will just keep a eye on it for now.

 

[Baker]

Greetings,
Mr. s. I believe Australia uses the metric system.

He put "c" in the initial post. But if his engines are running at 180c, he's in trouble!!!