Lost Thermostat Retaining Ring in Coolant System

[HandoEX]

Replaced the head o-rings on my 2016 Pro 800 today and found that the little retaining ring was gone from the bottom of the thermostat and I can’t find it. I know these rings are really small but how worried should I be here? Do these usually damage the water pump impeller when lost?

 

[HandoEX]

Anyone have experience one way or the other with the tiny retaining ring on the thermostat falling into the coolant system and getting lost?

Trying to decide if I should tear things apart to try* to find it or just send it and bring a water pump cover, impeller and gaskets on trips this season. Ugh

Anyone?

 

[gdn]

We actually had that happen once, found the ring in the cylinder water jacket. It did go thru the pump and put a small groove in the impeller and scratched the housing as it went around but it did not cause any real problems with cooling. You did put a new thermostat in though? Otherwise it won't open.

 

[HandoEX]

We actually had that happen once, found the ring in the cylinder water jacket. It did go thru the pump and put a small groove in the impeller and scratched the housing as it went around but it did not cause any real problems with cooling. You did put a new thermostat in though? Otherwise it won't open.

Thanks. This was a pointless thread. New stat and coolant yesterday and on the first start the impeller was already screwed.