I have a 2019 290EX with a Mercruiser 8.2l sea core engine that is overheating

tbecker

The engine alarm went off a few trips back. i checked coolant, which was low. I added the coolant and was fine for a couple more outings. Last outing alarm went off and the engine hit 220 degrees. had to leave cool down and finally limped back to my dock. I've heard that there is a problem with the heat exchanger on this engine. anyone heard similar or advice on how to repair? my mechanic thinks its a bad impeller, but cant' figure out how to get down there to replace that

LaRea

Trust your mechanic.  It's almost certainly the impeller.  You need to change them every two seasons -- maybe three seasons if you don't mind taking risks.  If you don't know how to change the impeller, there are plenty of youtube vids ... or watch your mechanic do it.  

I haven't heard of widespread problems with heat exchangers.  But if the impeller shredded itself, the pieces might be lodged in the heat exchanger, so you should backflush it.  Youtube vids for that too.