Coolant temp overheating with RPM over 3.5

MiamiAG

Any engine mechanics out there?

So I have a 290ec from 2013 with the Volvo Penta D4 diesel engine. Full throttle for me is about 3.8, 3.9 RPM and about 29 mph.

Lately, if I take her over 3.5 RPM for any extended length of time, the coolant temp seems to climb over the limit and my alarm goes off. I have to decrease RPM below 3.5 and it cools down.

Any thoughts?

Thanks,

Art

PickleRick

Hows the water flow to the engine?  I think using your o.b.d. you can check your coolant flow in gph or lph.  Id want to make sure there are no water pick up issues, my circulation impeller is good and all hoses are good i.e. collapsible/getting soft from age.

Also check for sticky thermostat.  Diesels are usally hard to get up to temp and ive never had a thermostat in a diesel stick but if it indeed is stuck in the open position the coolant may not be staying in the block/heat exchanger long enough to cool properly in a higher rpm/load.  Thus leading to upper rpm over heat.  

Also as you're in Miami, home of the world's worst drivers, you're in salt water.  How is the raw water side of your heat exchanger?

Warm year round salt water is worse than the seasonal salt water in the cool waters of the Chesapeake.  Corrosion could be an issue.



As with anything else id start with the basics. 

PickleRick

Also, not many diesel fans on here.  I did forget to add while doing visual examination make sure your pump drive belt is tight and in good shape. Same with the belt that runs your engine water pump. Im assuming its a serpentine so if it was losse or worn badly you may have other issues present.

raybo3

Take the end caps off of the heat exchanger and clean it out. Very little with cause this to happen. Good luck and keep us posted.