SUDDEN OVERHEATING PROBLEM

B

bob7415

Member
Joined
Feb 19, 2002
RO Number
7570
Messages
7
Volvo 5.0L I/O which will show no sign of overheating until you exceed 2000 rpm. At that point it will jump to 180++ or higher. Freshwater flushing valve replaced, connections tightened, and thermostat replaced. No change with the problem. Also removed and checked the waterpump impeller (brand new in May 2006) and found no problem with it.

Risers and manifolds checked and replaced (8 years old) still no improvement. Thermostat removed and still no improvement - seems to be some sort of problem with insufficient water volume getting to the engine.

Looking for suggestions and/or comments to solve the problem. Boat is 8 years old, used in saltwater, kept on a lift and freshwater flushed after each use. Engine hours show 350 hours over 8 years.

Mechanic is now suggesting pulling the boat, dropping the lower unit and checking for some obstructions in the water line.
 
PROBLEM SOLVED - AND NOT ANY TOO SOON !!!!

When the O/D was pulled off and following a lenghty search, it was found that the 18" water hose in the O/D had a fractured plastic fitting that allowed air to enter the cooling system and hence the overheating problem!!!!!!!!!

My mechanic had never seen one fractured before and surmised that it was badly corroded and only when the O/D came up on plane did air enter the system resuling in overheating. No problem when it was at idle as the fitting was below the waterline hence no air into the system

The hose and fitting were replaced and all is well. I certainly hope everyone will put this scenerio in the back of their mind and not go through the situation I did to get it solved.

BRING ON SOME NICE WARM WEATHER SO I CAN ENJOY THE FRUITS OF MY $$$$$$$$.

BOB
 
Thanks for the update. This will surely help someone here at some time in the future.
 
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