Running hotter than usaual ??

[sebas54]

Merc. v6 alpha 1 4.3l
Hi after overheating i changed the impeller and housing and discover that the old impeller was in pieces. I went out with the new impeller installed, and new thermostat (160 degrees) and the engine was running hot. It was running from 165 - 175. the slower I would go the higher the temp went, the fast the opposite. It never went above 175. I just checked the risers and manifolds and they look fine(replaced about 2.5 - 3 years ago, always flushed), i also checked the power steering cooler and it was clear of debris.

Can pieces of the impeller cause the circulation pump to not function right? That is my only guess as to why it is running hot. i replaced the cirulator pump about 1.5 years ago.

What should I check.

By the boat overheating before I changed the impeller could the temp. sending unit be malfunctioning or something else could have gotten messed up?


Thank again.

 

[Bondo]

Re: Running hotter than usaual ??

Ayuh,... You HAVE to recover ALL the lost pieces of the old impeller...

Back-flushing from the T-stat housing, to the drive, with the drive off is usually enough...

 

[sebas54]

Re: Running hotter than usaual ??

Sh$t So have to remove the drive once again. Backflush means what exactly? Sticking a hose in the in water hose?

thanks

 

[Bondo]

Re: Running hotter than usaual ??

Backflush means what exactly? Sticking a hose in the in water hose?

Ayuh,... That would be easier than using a Bucket, 'n Funnel...

 

[sebas54]

Re: Running hotter than usaual ??

So the piece of impeller is probably stuck in the inlet hose not the exhaust.

 

[Bondo]

Re: Running hotter than usaual ??

So the piece of impeller is probably stuck in the inlet hose not the exhaust.

Ayuh,..... Usually,...
The 1st impediment to the flow of Crud through the cooling system is a pinch in the feed hose from the drive, or the P/S cooler, if so equipped, or the T-stat housing....
The exhaust is a Loooonnnnng ways down the pipeline....

 

[Pete104]

Re: Running hotter than usaual ??

Depending how many pieces you find, there may be some stuck in water pocket. That's what the copper tube goes into when you were changing the pump. Backflush & compressed air. I like to use an old sock or something to catch what ever is getting pushed back out.

 

[sebas54]

Re: Running hotter than usaual ??

Thanks for the info. When I had the outdrive off I checked the pipe going through the drive and installed a new pipe from the impeller housing , it was all clear. Also I used the hose to force water through the inlet hole in the transom. It was also clear.

when I did install the plastic pipe onto the impeller housing it was not sung. I don't think that would matter.