Running hot

[Mikep]

I have a vovlo Penta D4 300. Came over to Catalina yesterday and it ran hot. I can keep the 185 temp to 3000 rpm but once I move it up to 3100 I get to 196 to 199. Assume this is impeller replacement time? Is it pretty straight forward

Anyone done a barnacle buster treatment thru the raw water side? Any suggestions? I have been a gas engine boater for 20 years so the complex diesels are new to me

 

[Cutwater28GG]

could be time to clean the heat exchanger

would start with impeller. (I do this every year as impeller failure is a quick cheap fix but an expensive failure)

 

[bill46]

Be sure impeller is good. We had to rod out the air intercooler.

 

[Sweet Peas]

Dirty (boat) bottom will also cause symptom.

 

[knotflying]

You will get many suggestions, but you need to do things symptomatically and go with the easiest first.
- Check that bottom is clean.
-Check that sea strainer is clear.
- Check for good flow of raw water with strainer cap removed. If flow is slow check that intake is not clogged.
- Check oil cooler for weeds.
- Check raw water pump belt
-Check Impeller
- Check Heat exchanger