6bta overheat?

[Don Gardner]

I am new to diesel marine engines but I know they are different than the truck engines I am accustomed to. I have a Maxum 4100 SCR with twin Cummins 6bta 5.9 M3 330’s. I have recently had the after coolers and heat exchangers serviced at a local radiator shop that specializes in marine coolers. Also have a new sea water pump on the starboard engine and new impeller on the port engine. Both engines will reach 2950+ rpms and I normally cruise at 2600. At cruise both engines are at 196 degrees at the thermostat housing using an IR gun. That seems to me to be too close to the max temp of 203. The temps are about the same as before the A/C’s and H/E’s were cleaned. What else should I be looking at?

Topic

[Don Gardner]

Beautiful spot. As are all of the San Juan Islands and the Canadian Gulf Islands.

[Rob Schepis]

Don, sounds good and thanks for posting the update, always good when these discussions aren’t simply left open-ended.. I never heard of Sucia Island so I just Googled it. WOW, looks fantastic! ….. a neat history too.

[Don Gardner]

Just an update. We took a ride from Blaine to Sucia Island today and everything ran beautifully. 175 on the port side (plumbed through hot water tank) and 177 on the starboard side.

[Don Gardner]

Thanks Tony. Sounds like I’m right where I need to be.

[Tony Athens]

All of the new marine engines from Cummins come with 160F Stats, and when things are right, cruise below 180F with 170-175-ish normal..

Tony

1 user thanked author for this post.

islandhopperiii

[Don Gardner]

Steve

Yes. The instruments are within 1-2 degrees of the IR gun.

[Stephen Oliver]

Have you cleaned the instrument panel connections? I chased an overheat for a while, alarm going off etc, but quick clean and lost 5 deg C. Or are the instruments showing same as ir gun?

Steve

[Bill Desmarais]

New pump…..OK

[Don Gardner]

Bill

Starboard raw water pump is new. Port is in good condition with new impeller. I would be more concerned about a “running hot” issue if it was only one engine. 6bta’s are supposed to run between 181 and 203. My concern has been that 196 does not leave any margin to catch a problem if something goes wrong.

[Bill Desmarais]

Don,

Couple of comments.
I now own my 5th 6BTA 370.
The most recent one is in my little lobster boat.
I run a 160F Tstat, Temps run 155-160 at any rpm or load.

No issues running the 6BTAs at these temps.

I’d be concerned about the new 160 Tstat you installed masking an “running hot” issue with the engine.

You mentioned A/C and H/E were recently cleaned. How many hours on the raw water pump? How old is the raw water pump ?

IMO your engine should be running close to 160F.

IMO you may want to look into the cooling issue. No issue running 6BTAs cool.

Keep us posted.

Bill D

[Don Gardner]

160 thermostats

So I took Tonys advice and put in SMX 160 Degree thermostats. My 6bta’s (mechanical) are now running at 176 degrees at 2600 rpm. Is that an acceptable temp or too cold for these engines.

[Don Gardner]

Thanks for the reply Paul. Yes I do have fuel coolers. I checked them with a digital scope and they are clean. I have considered the 160 t/stats but knowing that diesels like to run at high temps I am apprehensive about that without exploring the consequences.

[Paul Greenhalgh]

Do you have fuel coolers installed (immediately after RW pump)? If yes then these should be checked and /or removed altogether….see lots elsewhere on this site for details. The experts here may well advise changing overnight to 160 t/stats…but wait for them on this.

[Author]

Replies