possible engine issue - thoughts? (5.7 mpi v-drives)

[Sea++]

I have a 2005 320da, 3rd season for me with the boat. A few days ago, running 3900 rpms (22kts with very heavy boat, full tanks, kids, dog, food, etc etc) port engine was powered down by the computer. I have the smartcraft gauges. port engine temp was ~170 after powering down, starboard was 158 (as it always is). Port usually is also right around 158, but they can both vary slightly maybe up to 162. Water temp probably 75 in LI sound now.

After stopping, putting into neutral, then back in gear, everything seemed ok, but I noticed considerable steam coming from the exhaust of the port engine. It is clearly running hotter than the starboard now. I can maintain about 161 temp at 1800 rpms, but any higher rpm with a bit of load and temp climbs right back up to 170 quickly before I dropped power again, not wanting to do any damage.

I was able to get home later that day by running the starboard around 4200 and port at 3300 with really almost no load on that engine and it kept the temp at 168. My thinking was if it climbs over 170 maybe the smartcraft system shuts it down.

Engine still sounds perfect, gets plenty of power, etc. But lots of steam out of exhaust, and heats up too much.

So, is this a water pump or impeller, or head gasket, or risers? I'd like to narrow it down a bit before letting the marina loose on it with a blank check. Thanks!

- Mel
Sea++
Westbrook, CT

 

[Bt Doctur]

service history? same impeller for those 3 years, start there

 

[Sea++]

No impellers replaced since I've had the boat, so they are probably due on both engines, they could be 5+ yrs old. Marina does all service work including winterization, spring commissioning, oil changes, etc. Only thing done was air idle control valves on both engines. Risers are new(ish) on one engine, original on the other. I believe the original risers are on the port engine also, probably not a good sign. We had an extensive survey done at purchase time, including laser temperature readings all over the place while boat at WOT, crazy that the guy (two guys actually) were doing that with the engine bay open out on the water, everything was in perfect like-new condition when I received it. I don't touch the boat, just enjoy it, its really been perfect since I've had it!

So I'll do impellers on both engines for sure.

 

[Mike Blake]

No question Impellers.

 

[Sea++]

Boat fixed - it was just the impellers, as pointed out by everyone here. Thanks all! So I will need to do these every 3 yrs max.