Volvo MD22 engine temperature overheating

[jeffatoms2]

We have a 1998 38 Ocean with the original Volvo MD22L engine.  It has 2600 hours on it.  Historical lyrics it has operated at 85-90C.  This year it has been running at 95C.  It seems too hot.  This year I have replaced the thermostat, cleaned the heat exchanger tubes, swapped the raw water impeller, and ran a wire bottle brush up the inside of the 130 saildrive.  I check the raw water strainer regularly.  Note, I no longer believe the issue is with the raw water side as the amount of water in the exhaust seems adequate.  Also, the engine runs at 70C when the water in the hot water heater/calorifier is cool/cold and as that heats up, so does the engine temp.

We typically operate at 2400RPMs.  After anchoring last night, it stayed hot for 15 minutes at idle.

Does this feel like I am about to experience a fresh water pump failure?  What temps are normal for other non-turbo MD22L's?  Could it be a clog in the coolant system or time to take off the entire heat exchanger?

[Yngmar]

90°C is normal, 95 is nothing to worry about. If you don't get the overheat warning, everything is fine. Don't know why you'd expect a running engine to drop below its operating temperature once it has heated up - the thermostat is there to prevent this sort of overcooling. A failed thermostat means the engine doesn't reach temperature.

If you don't get a temperature warning, stop worrying about it

[JEN-et-ROSS]

You asked if...

  Could it be a clog in the coolant system or time to take off the entire heat exchanger?

Can I ask when was the Heat Exchanger last cleaned out..?
If it wasn't recently, it would be a good idea to strip it down and clean it and check/replace the impeller at the same time..

As indicated by Yngmar, the thermostat is there to maintain a set engine temperature, so even at idle it'll remain @ approx 90-95 Deg as the T/stat partially closes, and it'll progressively open as the throttle is advanced...

This will also apply to compensate for a few blockages in the Tube Stack, or a missing impeller blade, The T/stat will simply open further to increase the flow of coolant to maintain the correct temp but it can only do so up to a point.....
I think if your concerned, have a peek inside the H/exchanger and raw water pump.....

[jeffatoms2]

Last cleaned the engine heat exchanger tubes a month or so ago.  90-95 seems hotter than I recall.   Good news is another Bavaria 38 Ocean (1999) just pull into the anchorage from Annapolis MD, USA so we are going to compare notes.

[JEN-et-ROSS]

Last cleaned the engine heat exchanger tubes a month or so ago.  90-95 seems hotter than I recall.   Good news is another Bavaria 38 Ocean (1999) just pull into the anchorage from Annapolis MD, USA so we are going to compare notes.

In that case I totally concur with Yngmar..... Just enjoy the yacht, 90/95deg is roughly what it should be. Bear in mind these Temp. gauges aren't very accurate anyway............

[nightowle]

You could purchase an inexpensive laser thermometer gun that will give you a direct readout from different areas of the engine.  I only have the idiot light and alarm without a gauge, so this helps sometimes.  I've been experiencing the alarm when running at higher RPM for a length of time and need to investigate further.

https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html