7.4 VOLVO overheating

[frank j]

raw water fed, new raw water pump new thermstate, new manifolds and risers, new belts, runs fine at low speeds but at 3500 rpm starts to overheat than drops back to normal.
start up again to 3500 rpm and runs fine for a few miles than temp creeps up to 190 degrees same thing over and over ??? going nuts

 

[Scott Danforth]

How is the hose, and raw water inlet casting at the Out Drive?

 

[frank j]

hoses are new and inlet pipe where hose connects to the out drive seams ok no blockage or deterioration
it almost seems like there is a blockage that floats around and than catches and blocks the water flow.
thanks for your help

 

[Scott Danforth]

Back flush the system and hoses

 

[Lou C]

Get an IR temp gun and take readings of your risers and manifolds after running on plane. They should not be over 150 at most. If they are you may have clogging not allowing hot water to leave fast enough.
While the manis and risers are new what about the Thermo housing? Are the hoses getting equal water feeding the manis on both sides?

 

[bruceb58]

What is your model number?

 

[frank j]

WILL TRY back flushing and checking to see if equal amounts of water are coming out of each side
thank you