Overheat Alarm past 4000rpm

[flatsdude3]

I have a 99 Nissan Ns50d2, it has been running great except recently the water alarm will go off if I run past 4000rpms. I have a good stream of water from the tell tale until I go over 4000. As soon as I go past 4000 the water stream weakens and a minute later the alram goes off. I replaced the water pump just before summer. Any ideas on what it might be? Thanks

 

[TOHATSU GURU]

Re: Overheat Alarm past 4000rpm

Probably the water pump. If you replaced the impeller and did not replace the wear plate and liner it has probably prematurely worn out the impeller.