340 Da Engine Temps

[The W.A.V.E.]

Can anyone tell me what your normal operating temps are on 7.4l engines. Ive recently replaced the thermostats that were clearly stuck open and my temps havent changed from the 120-125 range. I think its much better than running hot, but someone told me that fuel burn is not as efficient at lower temps and neither is gas mileage or performance. These engines are in a 1999 340 DA. Thanks for any info.

 

[wickeral]

I would get an Infra Red Temp. Gun and shoot the Thermostat Housing. This will be close to the true Temp.. I suspect your Temp. Senders may be the problem. Change them out. Al W.

 

[Chris R]

Not much help here, but the 8.1's are about 165. Seems they shouldn't be too far off of that regardless of engine size.

 

[dpvandy01]

Previous boat 7.4l around 165 to 170, new boat 7.4 160

 

[NorCal Boater]

My '89 340da has 7.4s. When I bought it 2 years ago the engines ran at 125. I knew that was too low so I opened the cooling system, flushed the closed cooling portion and installed new 165 degree thermostats. The old ones were 125s. She now runs a very steady 165 except for the starboard engine that will creep up as high as 180 and then go right back down to 165.

Not sure why yet but everything runs great.