engines running a bit hot

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kashurst

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had the volvo boys (oscar marine) on board yesterday to check a few things on my KAMD 300s
generally all is very well but they are both running a bit hot. Apparently around these parts the temperature gauge should sit @ 85 degs C, mine are both just over 90 degs C. Sea around here is @ 30 - 32 degs at the moment.
Oscar suggests an acid rinse (not sure what solution he is refering too) as in their experience it will shift the scaling easily at this level of gunked up.

I am vacilating between stripping the cooling systems completely or setting up a pump and circulating a descaling/cleaning solution. Full strip will take longer but I know its really clean everywhere, but I will still need to soak the heat exchanger inserts in something to get the scaling off. Rydlime is the obvious choice but I can't find it around here (Alicante area) any other suggestions.
 
I had mine done in Cala dor. Cost e800. Not cheap but it was running hot and could be done next day. Temps dropped about 8 degree.

Volvo d12 now run at between 78 -82 depending on throttle. Was up to 90

If doing yourself I would also do gen ( he did a quick one by pouring into filter and leaving for half a hour. Also the ac. It gets clogged also so it nice to get clear.

I would do that. Stripping sounds like a lot of work and if acid works the. Leave well alone. He commented seals alone were a lot of money.
 
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Rydlyme is the stuff. Internally, drain the coolant, replace with Water and 30% Rydlyme, run for an hour at idle, drain and replace with fresh coolant. It may fizz up a bit, and keep an eye on them temperature-wise. You'll be surprised what comes out...For the Freshwater side, run a reverse flush from the exhaust water feed forward to the raw water pump, either into the bilge or buckets, recycling for a couple of hours at 30% concentration. Don't run the engine, but you need to make sure the water exiting the front is lower than the mix being pumped in (12v inline pump!) Worked wonders for my TAMD40b's. It doesn't hurt the engine, nor your fingers, nor GRP so safe to slosh around in a ventilated area. You can probably reuse the Rydlyme on the other engine if you add a bit of fresh...
 
Definitely try Rydlyme first. If you can't get any locally and am prepared to wait till early October I will be driving down to Altea so could bring some out with me. Send me a PM if required.
 
I had a kad 300 powered boat once .
Similar issue but only one side 92 from memory ?- on the guage .
Vp engineer used a laser thermometer on the top of the thermostat housing @ sea trail in the bay
Both engines 85
He was an employee ,@ the local yard a big outfit ,plenty of work on etc .
Told me common problem as time gets by the insulation on the umbilical ( back of the black box ) work hardens and the resistance in the wire changes leads to false readings on the kad 300 ,Temp dials Allways up -this the "way in " for a self employed or not so busy outfit with a thin dairy .
To prove this you can just about unplug them and swap them ,he did and other guage went to 92 while the "hot " one stayed @ 86 .
Yours is both appreciate that .
Have you accurately measured the temps ( wife Helming @3200 rpm ) with a laser thermometer on the thermostat housings ?
Not saying its not time for an acid clean or cooler strip down .
Just in my shoes knowing the above I would want a confirmation of the actual temps -not what the guages say ,before tearing open the engine .

Appologies if your engineer has allready done this. But it's not obvious in the post .
Hopefully anybody else with " Hot " 300 kad may benefit .
 
Portofino said:
Have you accurately measured the temps ( wife Helming @3200 rpm ) with a laser thermometer on the thermostat housings ?
Click to expand...
+1.
Nowadays that IR guns can be bought for peanuts, it's crazy not to have one onboard.
Even swmbo loves it, to check sea water temp and decide whether to put her wetsuit on or not... :D
Best thing since sliced bread.
 
have ir temp gun and they are running a bit hot. got suitable rydlyme equivalent now from local volvo people. thanks for the offer to bring some out, but fingers crossed should be sorted now
 
just an update; flushed cooling system out, temps dropped @ 5 degrees. Gauges show just under 90. I took the boat for a good run out today and measured the thermostat housings with IR thermometer - both engines seem to be at 82.5 degrees. I measured the top of the cylinder heads too and got the same temp. I think that means my engine temp is perfectly fine but my gauges read a little high. Is the temp sender analogue or digital on a kad/kamd 300? If its analogue the error could just be poor contacts. Also where is the temp sender on a kad engine? cheers.
 
Looking astern it sits in the thermostate box RHS jammed down the side .
See my post #5 .
I dought new sensors will make any diff ,needs a whole new wiring harness or the temp wire part .
Just live with it .I did .
 
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