Volvo TMD22A. Over heating.

[Tommo66]

Hope someone can get me out of a situation with my mother.
Anything over 3500 ram my the overheat alarm goes off look out the stern and water has stopped pumping. Throttle back and starts pumping again.
Have had heat exchanger acid bathed and cleaned changed two end caps fitted new water pump but still no joy.
Any ideas would ba appreciated.
From a frustrated mariner.

 

[markc]

Has one of the hoses delaminated inside, as the flow builds, the loose flap blocks the flow?

 

[Mr Googler]

Why is your mum upset about this?

Impeller in good shape?

where’s the Seacock? Any chance you’re drawing air at speed?

 

[Tommo66]

Has one of the hoses delaminated inside, as the flow builds, the loose flap blocks the flow?

Hi Mark C I'm going down the boat after work to strip all pipes off I'll let you know tnx.