Normal Running Teperature

Bmaggiac

I just purchased a 2008 Rinker 330 EC. I love it but I have a question. I have twin Mercruiser 350 MAG seacore engines. I read that the normal running temperature should be 170 degrees. Both my engines run at slightly above, 175 to 180. Should I be concerned or is this ok?

aero3113

Welcome to the forum! I have the exact same boat!!
My engines run the same temps as yours.

aero3113

aero3113

You can’t trust the Faria gauges 100 %. Only way to get accurate readings is to go digital.

Cableguy Greg

Mine show that temperature on the gauges as well. When running with my VesselView Mobile app, the temp on the app is around 162. I trust the app more than the gauge. 

Liberty44140

Yep my 342 with 350s ran the same. They matched on both sides so it never gave me concern. The new owner of that boat put in vessel view and found that the gauges were 10 degrees high. 

Handymans342

Don’t you guys think that’s kinda cool? A car runs about 210??

TonyG13

I also have 350 MAG Seacore (2014) and they run at 162.

Cableguy Greg

Handymans342 said:

Don’t you guys think that’s kinda cool? A car runs about 210??

Not at all. The thermostat is a 160* stat. 

Liberty44140

Yea I had thought RWC merc ran around 140-145 and FWC merc ran around 160-165? 

Just for you @Handymans342 my diesels run at 185F on the dot! 

Handymans342

I know when the thermostat sticks open on a car it runs cool but the computer thinks it’s cold and runs a richer program. Maybe the computer is programmed on boats to see 160 

aero3113

Handymans342 said:

I know when the thermostat sticks open on a car it runs cool but the computer thinks it’s cold and runs a richer program. Maybe the computer is programmed on boats to see 160 

Funny, my port thermostat stuck open this weekend. Once I got up on plane it must’ve cleared something and was back up to my normal running temp.

YYZRC

Handymans342 said:

Don’t you guys think that’s kinda cool? A car runs about 210??

Most cars don’t run at 3500+ RPM sustained. 

Handymans342

YYZRC said:

Handymans342 said:

Don’t you guys think that’s kinda cool? A car runs about 210??

Most cars don’t run at 3500+ RPM sustained. 

That’s irrelevant

Grahamu

Most marine engine thermostats are either 145F or 165F gas or diesel.

Handymans342

Mine were 180

Grahamu

I said most

PickleRick

140 in salt to prevent  salt build up and 160 in fresh water.


This is for raw water cooled motors.  Although many report using  160 in salt water for decades without issue.  


My diesel runs 175 at idle speeds but 210 at wot  which is well within range for my VM Diesel. This is closed loop.


@Handymans342 is correct that the same votec motors used in many of our boats  (closed loop) are identical except for the cam and some marine rated electronics as the 5.7 votec found in the same year 1500 gmc pickup.   They also run about 220.

Maybe someone with closed loop cooling can chime in and tell us what temp their 5.7 motors are running. 

I was always under the impression that the newer votec motors ran more efficiently at 200 to 210 vs the 190 of the 4bbl  4 bolt main days of small blocks. 

Liberty44140

Handymans342 said:

Mine were 180

I can’t believe you missed the diesel reference above….

YYZRC

My 330 had 5.7 with closed cooling and 160 t-stats. 350 has 6.2 with raw cooling and 160 t-stats. 

PickleRick

YYZRC said:

My 330 had 5.7 with closed cooling and 160 t-stats. 350 has 6.2 with raw cooling and 160 t-stats. 

Thank you!  Good info! 

Spyderweb

My 330 with 350 mag raw water cooled run 154-156 on the vessel view mobile.  The gages read something like over 175.  Love the VVM.

aero3113

Spyderweb said:

My 330 with 350 mag raw water cooled run 154-156 on the vessel view mobile.  The gages read something like over 175.  Love the VVM.

WoW! That’s a huge difference!! I wonder what I’m actually running. I guess I can hook up my Rinda and find out.

Bmaggiac

I feel better now. Thanks for all the great feedback!!!