KAD 300 overheating

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greggreystones

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Hi
Not experienced with engines at all, only had the boat a couple of months, but went out today and one of the engines overheated (alarm went off), so turned it off immediately. Once back at port opened up engine bay to find all the fluid from coolant reservoir emptied on floor (green coolant) but cap on reservoir was tight but wet (sound of hissing air escaping. Don't know if it is linked to water pump being replaced only 2 hours (running time) earlier. Any advice welcome
 
greggreystones said:
Hi
Not experienced with engines at all, only had the boat a couple of months, but went out today and one of the engines overheated (alarm went off), so turned it off immediately. Once back at port opened up engine bay to find all the fluid from coolant reservoir emptied on floor (green coolant) but cap on reservoir was tight but wet (sound of hissing air escaping. Don't know if it is linked to water pump being replaced only 2 hours (running time) earlier. Any advice welcome
Click to expand...
Which water pump, the sea water pump or coolant circulation pump?
 
greggreystones said:
Again not an expert but it was the pump which runs from the middle of engine with belts running off it
Click to expand...

The circulation pump, strange but maybe the sea water pump wasn't pumping sea water through the system causing the overheat. You need to start with the basics by checking sea water is circulating the system to cool the heat exchanger.

Why did you need a new circ pump?
 
The water pump was diagnosed that it needed replacing when the alternator belt broke and the mechanic found that there was 'slack' on the water pump wheel (which belt goes round) so recommended it be replaced
 
Ok, if it's the circ pump there has been a faulty batch whereby the shafts sheared not allowing the impeller to turn causing an overheat , I'd get him back to run the engine up to temp and check for flow. Also check sea water is being pumped through the system and the thermostats are opening.
 
I had a KAD 300 engined boat for 9 y .One engine started to run hotter than t,other .
Infra red thermometer is use full -compare with the good un ,and confirm guages are true .They have a wiring loom issues caused by heat deteriation -also effects the guage readings -
Any how you do have an overheat -it's blown the coolant .removing the thermostats helped a bit

Mine turned out to be corroded exhaust elbow spray ring .I was horrified when I took it off and looked inside .
about £160 off E Bay for after market one .As the holes in the ring close up by rust -seawater can,t escape as fast = overheat -comes on ever so slowly and is speed related .
I remember some American Web site doing Stainless Steel ones ,but at a price .
When the elbow s off more horror sights look down at the top of the riser -that too is made of junk metal and the edges will be nibbled by corrosion -there's is a rubber aftermarket repair kit for that too -agian "Stateside "
TBH I was a bit disappointed by the whole build quality of VP in this case and sold the boat ,mindfull next time of a better built quality -material wise in the replacement .
The ownership experiance put me off VP -for ever chasing corrosion issues of the external bolt on bits .

Ps had water pump issues -,not from snapped shaft from leaky seals -worn bearing -you see the paint bubbling up - can,t remember think just taken off and reconditioned was early on like boat 3-4 y old !
Leakey shaft seal did not cause overheat issues just sprays sea water about -Alternator is v close not good !
That allready gets is own dowsing when you open and check the strainers

I,dd better stop :)
 
Last edited:
Portofino said:
I had a KAD 300 engined boat for 9 y .One engine started to run hotter than t,other .
Infra red thermometer is use full -compare with the good un ,and confirm guages are true .They have a wiring loom issues caused by heat deteriation -also effects the guage readings -
Any how you do have an overheat -it's blown the coolant .removing the thermostats helped a bit

Mine turned out to be corroded exhaust elbow spray ring .I was horrified when I took it off and looked inside .
about £160 off E Bay for after market one .As the holes in the ring close up by rust -seawater can,t escape as fast = overheat -comes on ever so slowly and is speed related .
I remember some American Web site doing Stainless Steel ones ,but at a price .
When the elbow s off more horror sights look down at the top of the riser -that too is made of junk metal and the edges will be nibbled by corrosion -there's is a rubber aftermarket repair kit for that too -agian "Stateside "
TBH I was a bit disappointed by the whole build quality of VP in this case and sold the boat ,mindfull next time of a better built quality -material wise in the replacement .
The ownership experiance put me off VP -for ever chasing corrosion issues of the external bolt on bits .

Ps had water pump issues -,not from snapped shaft from leaky seals -worn bearing -you see the paint bubbling up - can,t remember think just taken off and reconditioned was early on like boat 3-4 y old !
Leakey shaft seal did not cause overheat issues just sprays sea water about -Alternator is v close not good !
That allready gets is own dowsing when you open and check the strainers

I,dd better stop :)
Click to expand...

I think you had better stop. If I was not put off a Volvo penta I am now

Dennis
 
Thanks everyone for your feedback, the engineer that did the recent work is going to have a look this week, he thinks it maybe the seal on the thermostat housing. Again a big thank you
 
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