Can an impeller partially fail? Dealer Issue #2

[redelf75]

More specifically, can the impeller be the cause of overheating one day and then be fine the next? Can it fail for a day and not again for a week or two and fail completely a month and half later?

Could the first two overheating issue be caused by weeds, even after the hull was inspected and noted as clear of debris?

[surroundsound64]

RE: Can an impeller partially fail? Dealer Issue #2

I would probably say yes, but not likely...

If you loose a few blades off of an impeller (2 or 3 or even more) they can block the water passages and cause the engine to over heat. Then they could blow out and the engine would be fine. However I have found my thermostat PACKED with impeller blades before and the engine not overheat. I don't know how, but it was doing fine.

I was changing my hose that goes from my impeller to the thermostat and I just happened to look into the thermostat and saw impeller blades. Who knows how long they had been there, but my engine always maintained 140-160.

Who knows.

[redelf75]

RE: Can an impeller partially fail? Dealer Issue #2

Thanks. If it's not the impeller, what else could it be? Keep in mind that the boat was put on the trailer and inspected and then relaunched and still overheated.

[east tx skier]

RE: Can an impeller partially fail? Dealer Issue #2

Check the screen in your transmission cooler for debris. They can get clogged up pretty easily.

[G-man]

RE: Can an impeller partially fail? Dealer Issue #2

There could be pieces in the thermostat also

[Rick]

RE: Can an impeller partially fail? Dealer Issue #2

It could be a sticky Thermostat as well. If you have lost pieces of impeller in the past I would check the path from the thru-hull to the thermostat. Some pieces may change position and block then not blocl the hoses. Also you can run without the thermostat. If it overheats then it is definetaly a water flow problem.

[NautiqueJeff]

RE: Can an impeller partially fail? Dealer Issue #2

You might also want to check the coolant level. The closed cooling system on that engine may be running low on fluid.

[triplered]

The waterbowl could easily be clogged too. If you check it and clean it, be careful not to lose the gasket that goes in the bowl. If you lose it, you'll overheat for sure.

If you were overheating on the high end, but not the low, the culprit is usually impeller pieces caught up in the thermostat. If overheating on the low, but not the high, the culprit is often the waterbowl clog or impeller.

It's really easy to forget to check the hoses that go to the water pump for impeller pieces. You might blow out all hoses when completing an impeller change.

[Hydrofoilmaniac]

I can't speak for the new boats (1985 is new to me) but the main supply hose on my boat is connected to the transmission oil cooler (tube & shell cooler). I've seen debris in this before that could result in a reduced flow to your engine, since it passes thru this cooler first. Something to look at if you run out of things to check..........

[Nautiqueman]

I have had two cooling/overheating issues that may help you with the problem:

water filter bowl and gasket need replacing, a small crack almost unseen caused overheating and

i had an impeller that clogged the water hose BEFORE the impeller and water pump

[redelf75]

thank you all for your replies.

OTW and Hollywood will be pleased to know that my impeller has been successfully been changed and the boat's cooling system is working perfectly now.

As the boat overheated twice at headway speed or on the trailer and did not overheat when the dealer did a watertest at cruising speed, suggests that the impeller was unable to create enough suction to draw water without the added benifit of forced water. In this regard, the impeller had a partial failure.

[Onthewater]

I didn't post anything on this topic and I get mentioned, how sweet, seriously what is your problem? Get a clue.

[MiracleDriver]

can an impeller that looks perfect still fail?

[richard]

No,but Sherwood raw water pump not ideal for GT-40 engine,if can,I'll change a bigger pump,IMHO