1/2 260 Penta's running hot

[Katmand]

My Cat (Seasport Pacific) has Twin Diesel 6cyl 260hp Volvo Penta KAD 44 EDC with about 700 hours on them. All of a sudden one of them started running about 25 degrees hotter than the other. At cruise (about 3200 rpm) it's about 210 where the port engine is about 175-180.
Back it down, same thing, both cool but Stbd is always about 25 deg hotter. Have gauges on the fly bridge and inside and they both match so not bad gauges.

Did the easy stuff - strainer is clean, good water flow, impeller is basically new with no rubber degradation. An engine oil sample came up with just SLIGHTLY elevated levels of Al but everything else was good. Looking for help with the best next steps... Thanks... been reading all your fine posts for months and finally have my own problem

[Neptune's Gear]

Compare coolant water flows from the exhaust - sounds like a raw water blockage to me, so through hull, strainer, or heat exchanger. I had a fish in my intake once!

[Diesel Bill]

I agree with Neptune's Gear. Most likely cause of overheating is less water flow. You need to determine why. Blocked inlet to strainer, bad impeller, blocked heat exchanger, bad thermostat. Low coolant level (leaks), collapsed hose, blocked exhaust muffler. The list is long so get to work and let us know what you find. Good luck.

[sailah]

I vote for heat exchanger being clogged or necked down from salt deposits. Had the same issue on my engine although not a Volvo. Right where the hose from raw water pump comes into heat exchanger was blocked about 80%. Removed, cleaned, reinstalled, perfect.

My temps dropped from 205 to 180 instantly.

[Katmand]

Thank You for the great suggestions!!... I'm going to take the boat out tomorrow into clearer water and trace as much as I can from the through hull to the heat exchanger and let everyone know.

[Cadence]

Originally Posted by Katmand

My Cat (Seasport Pacific) has Twin Diesel 6cyl 260hp Volvo Penta KAD 44 EDC with about 700 hours on them. All of a sudden one of them started running about 25 degrees hotter than the other. At cruise (about 3200 rpm) it's about 210 where the port engine is about 175-180.
Back it down, same thing, both cool but Stbd is always about 25 deg hotter. Have gauges on the fly bridge and inside and they both match so not bad gauges.

Did the easy stuff - strainer is clean, good water flow, impeller is basically new with no rubber degradation. An engine oil sample came up with just SLIGHTLY elevated levels of Al but everything else was good. Looking for help with the best next steps... Thanks... been reading all your fine posts for months and finally have my own problem

Have you checked the temp. sending unit and gauge. You maybe beating yourself up over basically a non existent problem.

[pesarsten]

Why not get an IR thermal sensor and compare temps on the two blocks at different areas.
I would want to confirm the problem before I started wrenching.

[Katmand]

unfortunately the seas were a bit too rough this weekend to get under the boat. I'm pretty sure it's a legitimate temperature issue because the 2 engine were tracking just fine a couple of months ago. Also, I have 2 sets of gauges (flybridge and main cabin) and they are both saying the STBD is running hot. I was able to pull the hoses to the heat exchanger and they look OK and good flow at idle. I'm suspicious of the thru hull intake, water can get a bit mucky back in my inlet. If the seas don't lay down soon I might have to just haul it out...

[Cadence]

Do the two gauges on the engine share the sending unit? It may sound stupid but tap the sending unit/s with something like a screwdriver blade. As you can probably tell I had one drive up the wall. Plenty of grey hairs for a couple of dollars sensor. Naturally located in the most inexcusable location.

[Katmand]

Hey, it certainly can't hurt to give that a try, l let folks know what happens. The seas look to be laying down Fri - Sat so I'll be able to get a good cleaning of the thru hull as well.

[Katmand]

Soaked the raw water system in barnacle buster and flushed, noted great water flow. Replaced thermostats. Penta digital temp gauge confirms the one side is still running about 15-25 degrees over. Ug.