Air lock??

[Darren1]

Hi. Just changed impeller on kad32. Very bad overhead last weekend with most of coolant in bilge. Trying to get to the bottom of it so first put new impeller in now I think it might be air locked. Face plate is cold but strainer is full and overflowing. How can I clear a potential air lock. Any help is greatly appreciated thanks

 

[Seastoke]

Can fill hose coming off pump from above

 

[Mr Googler]

Air lock on the seawater side?

impeller pumps into the strainer so don’t run it with the lid off

 

[Darren1]

Hi. Thanks for the replies. I’m not running it with lid off. Put new impeller in ran engine for 20-30 seconds then checked on things. When taking strainer lid off (water leaking out of tightly fitted lid) the strainer was full and water continued to come up like it was under pressure. So I think the impeller has lifted it up but it doesn’t seem to be going back down and through the engine. Which make me think there’s an air lock some how. Normally when I remove strainer lid (engine off) the water level falls. Thanks

 

[dpb]

isnt the new impellor holding water in the filter that used to drain out past the old impellor?

 

[Mr Googler]

Hi. Thanks for the replies. I’m not running it with lid off. Put new impeller in ran engine for 20-30 seconds then checked on things. When taking strainer lid off (water leaking out of tightly fitted lid) the strainer was full and water continued to come up like it was under pressure. So I think the impeller has lifted it up but it doesn’t seem to be going back down and through the engine. Which make me think there’s an air lock some how. Normally when I remove strainer lid (engine off) the water level falls. Thanks

Are you on outdrives? Pull the rubber water pipe off the exhaust elbow and run….you’ll soon find out if you’ve got water flowing

 

[SC35]

Are you on outdrives? Pull the rubber water pipe off the exhaust elbow and run….you’ll soon find out if you’ve got water flowing

No, do not do this, your boat will sink.
Did the old impeller come out complete, or did it break up into bits?
If it broke up, you might need to remove the heat exchanger / exhaust elbow.

 

[Mr Googler]

No, do not do this, your boat will sink.
Did the old impeller come out complete, or did it break up into bits?
If it broke up, you might need to remove the heat exchanger / exhaust elbow.

Will it heck. poke the hose in a 20 litre container And shut the engine off when it starts to fill

if you left it running 20 mins…maybe

how would the impeller pieces get past the strainer….and oil cooler….and intercooler ….then the heat exchanger stack to the elbow

 

[SC35]

Will it heck. poke the hose in a 20 litre container And shut the engine off when it starts to fill

if you left it running 20 mins…maybe

how would the impeller pieces get past the strainer….and oil cooler….and intercooler ….then the heat exchanger stack to the elbow

Dunno, but it happened to me.
I had bits of impeller all over the place.
Even found some pieces in my wallet

 

[colhel]

In the first post the OP says "most of coolant"in the bilge, does this point to more of a problem in the fresh water circuit?

 

[colhel]

Also, if the face plate is staying cold, doesn't that mean sea water is flowing through? I'd have thought if there was a blockage the pump would get warm as the sea water would have nowhere to go.

 

[volvopaul]

On a stern drive with the strainer after the pump the bits will be in the basket , but some will also be in the pipe from the transom shield to the pump , if that’s the case then you may get a slight blockage as the bits jam up on the impeller .

 

[Darren1]

Hi. It’s all good now been up the river for a couple of hours no anglers around so had a good test. Thanks for the replies