What temps do your 3208s cruise at?

[Bongi]

Our twin 3208N GB42C is by far the best of our 9 boats we’ve owned over the last 20 years. What I am curious to know is:

1. At what temp do your temp regulators (thermostats) open at?
2. At what temp do they run at when up to temp?

My PORT engine will open at 200F and settle down at 190F. That seems quite high…

My STBD engine opens it seems at 165F and runs at 160F… which I am beginning to suspect is a sensor that is under reading… as confirmed by IR gun.

What’s normal here?

 

[Alguires]

Pretty consistent 170-175 both engines over the last eight years, eight hundred hours. 1986 42CL with Cat3208na.

 

[tiltrider1]

I run 180 very consistently on both engines.

 

[heysteve]

Our 3208 natural stays about 165 but we only cruise at 1500-1800 rpm. The only time I ever saw 180 was during the sea trial when we cruised a bit at 2300 (and threw a wake like a destroyer!).

 

[DennisB1]

3208 TA 375. 1200 to 1600 about 175F both engines

 

[RobertLeatch]

My 1980 3208NA both run consistently at 180F.

I believe that at some point Cat increased the opening temp of their thermostats to open at a higher temp (+10 degrees) as part of improved emision controls.

 

[RickyD]

I have the 3208 TA I believe that are the 425hp variety. My happy cruising place is 1650 to 1750 running 9.5 to 10 knots. Both engines run at 177 as confirmed by heat gun. Port engine gauge is correct, my stb gauge jumps around. Actually showed 250 yesterday for a time then dropped to 195. I need to find the bad connection that is causing this problem.

 

[Bongi]

Excellent folks - this is precisely the kind of information I was looking for.

This helps a ton, and guides me on what a healthy engine should be doing.

now it's just a matter of getting them both to that happy place.

 

[Southern Boater]

My 1980 3208NA both run consistently at 180F.

I believe that at some point Cat increased the opening temp of their thermostats to open at a higher temp (+10 degrees) as part of improved emision controls.

Something to be mindful of when buying new thermostats/water regulators from Cat, I was given the higher temp version after quoting my engine serial numbers, and had to take the very heavy and awkward to handle (coolant) heat exchanger back off to put the original lower temp versions back in!

I also have the 3208 NA versions.

Also if one of the engines is supplying coolant for the hot water cylinder HE, that circuit will take longer to get up to temp, and check where the engine sensor and helm gauge wire terminals join (on the engine) for good connectivity.
I’ve recently re-terminated all mine with many loose, poorly connected, giving inaccurate helm gauge readings.

 

[motion30]

My Motors we're around 180 at 13 or 1400 RPM. Installed new thermostats closer to 190 and 195 now

 

[bowball]

What's the advantage of the higher rated thermostats? Did they think the engines weren't getting warm enough at 175/180?

 

[rslifkin]

Generally, hotter running engines will burn more efficiently as long as the extra heat doesn't cause any other issues.

 

[Sykes]

3208N in So FL and Bahamas - 187 never changes.

 

[Jetwag03]

38 foot Californian with 2 3208 300hp turbo's, indicated temps are at 1500rpm 180 and it will go to above 190 running wide open, I like to cruise 8-10 kts then run them hard after a few hours to burn off any carbon.

 

[motion30]

What's the advantage of the higher rated thermostats? Did they think the engines weren't getting warm enough at 175/180?

Honestly I did not know they were hotter rated thermostats. But actually I am good with that cuz I run the motors easy and I think the hotter temperature is less likely to carbon up the motors

 

[Portage_Bay]

3208 NA, 1600 RPM, 180 at the thermostats. Run them up to 1800 - 2000 RPM for 10 min / day. No obvious change on the gauges at the helm.

 

[Nomad Willy]

“I run my engine at 1800rpm w coolant at 180 degrees f.”


Dosn’t mean much.
There could be five reports one right after another w considerably different numbers. Thermostats vary, tachs vary but mostly LOAD varies. Even if the reporter has the same engines at the same rpm. Gear ratio, propeller diameter, and pitch vary a lot not to mention the heat gun or dash instrument. Way way to many variables for the numbers to mean much. Unless things have changed many over-prop and some (like me) underprop about 100rpm.

But it’s fun to compare and wonder.