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KAMD 300 A Overheating

Bigvtwin1

Contributing Member
The other day heading out in the fog i briefly hit bottom doing only 5 kts, backed out without getting stuck. Later on after about 3000 RPMs the engine started overheating so i had to back down to 1000 RPMs all the way home for about 8 miles. Any faster the temp started to climb. At one point the temp alarm went off, lost some of my coolant. Checked for a split hose or something, found none. Added a gallon of water and kept speed down to 1000 RPMs and was ok for the ride home. At the dock just idling, for 5 mins temp was 200deg. once i put the fresh water hose on to flush, the temp went down? Could i have mud in the raw water cooling system? Any one with experience with something like this please reply or anyone who knows what this could be. I primarily do all maintenance on my engine and I can't figure this one out.
 
OK, Now that my engine has cooled down I was able to take another look, When squeezing the hoses I see water dripping from the main fresh water pump. Anyone know what this repair job entails? Obviously I need to order a pump kit but how in depth is the tear down?
 
Where is the dribble coming from? Is it from the 'drip hole' behind the impeller casing part of the pump or somewhere else? I don't know that particular pump but if it is like most raw water pumps it is a pretty simple tear down and a new seal to be fitted. Should probably look at doing the wear plates,impeller etc whilst you are at it. Seal is probably available from your local seal&bearing shop for $10,as will be the bearings. Other parts are from Volvo or the pump manufacturer (Jabsco, Sherwood or whoever). You will need circlip pliers and maybe a small bearing puller to make life easier. Pretty simple job if it is just a bad seal. The leak possibly means that your pump is sucking air and hence not enough water flow.
 
No its not the raw water pump, its the main water pump where the water is dripping, also i had to add water to the system. I have done the raw water pump with the wear plates too a few years back. I'm looking at changing the seal and bearing on the main water pump. Do I have to remove the idlers and the pulleys along with the pump?
 
Update to previous, i pulled the main water pump and found the top seal from the thermostat housing to the pump housing had been leaking along with bearings being worn, could not tell if the shaft seal was passing but probably was. Could not tell if weep hole was passing or if water was dripping from the upper rubber seal. Ordered both bearings and seals along with both thermostats
 
If they are like the other Volvo ones I have done the fitting of the mechanical seal is a very tricky process so be very careful not to break the mechanical seal as you fit it. I think that there may also be a spec for the clearances of the vane plate as you reassemble it that you may need to look up.
 
OK, i have the pump rebuilt and having real problems getting the seal between the thermostat housing and the pump. I have enclosed a breakdown of the water pump and will be sending a breakdown of the thermostat housing so you know which seal Im talking about. When you are trying to line up the pump its impossible to get the seal to fit properly between the housings. Once you think you have it you can see an area when the seal is folded in and not sitting right. Please help I'm going crazy with this. The seal is #6 in the thermostat housing breakdown and in the other breakdown of the pump you can see where it goes. Its like a wedge fit you can't lines the bolt holes up with the seal in place and when you try and install one bolt in on the left top on the pump you can't get the seal in properly.
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Sounds a lot like the same thing on our KAD32's. The only answer I ever found unfortunately was to keep trying until you got lucky. A real PIA but sorry I haven't got a solution. Maybe someone cleverer has worked out one and will post.
 
Thanks for your reply Aliboy, i was going to try and put a little grease around the seating surfaces and maybe that would aid in the correct position. The problem is that you cannot see the back part of the seal to see if it is entirely fitted. Also you cannot drop the pump down even half an inch to allow the seal to release from the part where its hanging up. Do you think its out of the question to remove the thermostat housing first, install the pump, then install the stat housing on top? I only see two bolts holding it from the front of the engine. Is it fastened to the engine on either side? And is there a gasket between the thermostat housing and the engine? Need direction?
Appreciate any advise from you or anyone else that has had experience with this.
 
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