Thermostat Full Open Question

[Nestor]

Newby to Cummins diesel and this forum. Recently replaced tstat on 5.9 Cummins using OEM 3802968. In addition completed flush on both directions, replace raw water pump and removed aftercooler for maintenance following Tony’s tips. Motors run at 195F tested up to 2800RPM. I read on the web this thermostat begin open at 181 and full at 203F. Is that a correct statement?
If correct should 195F safe on these motors.? I still need to confirm temperature between gauge and temp thermal gun

Thanks

Topic

[Rob Schepis]

Nestor wrote:

I’m doing all required maintenance first before switch on tsat.

Good plan.

[Nestor]

Thanks for your recommendation Tony. I’m base in the Caribbean with warm waters. Read your article on the 160 Tsat for the B series. I’m doing all required maintenance first before switch on tsat. Agreed on the recommendation since 195 doesn’t provide enough margin.
-Nestor

[Tony Athens]

Much depends on the water temp you operate in,, In S Calif, 65F is common, Florida, 80F seems to be the norm..

Yes 195 F is safe, but on a “B” Cummins in a boat that runs on plane, IMO, not enough safety margin for me…………….Ask your why all the new QSB’s, QSC’s, QSL9, and 450 Diamonds use 160F stats??

IMO, 180 stats have their place ( and in general, is more efficient) , but 160F should be the norm..

Tony

[Author]

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