Mercruiser 165, possibly water pump issue?

[tekknosk8er]

Hello, I have a 1989 Rinker with a Mercruiser 165, 4cy.

My question is:

My motor went out the other day, it made a loud winning noise then a ton of smoke/steam came off the motor. Engine overheated, and I shut it down immediately. Opened the engine compartment and water sprayed everywhere. I have owned the boat 2 seasons and not sure what repairs have been done or needed, I change all the oils regularly. When I pulled the boat out of the water Green Antifreeze poured out when I pulled the plug. When this happens is it usually the circulating pump that causes this? Or an impeller that causes the pump to fail? Please help!

 

[Bifflefan]

Re: Mercruiser 165, possibly water pump issue?

My guess is the seals in the water pump on the closed cooling side. There are 2 seals on the cam shaft that keeps the water in the system and out of the oil. They are not had to change, but hard to get to. You have to pull the engine or at the very least, the front mount off, remove the balancer and front timing cover. The seals are in the timing cover and there are 2. About 18.00 each and you may need 2 speedy sleeves. About 40.00 each.

To test for the leak in the driveway. Fill the closed side with coolant 50/50 or colored water so you can see it. hook up the hose and start the engine. On the port front side of the engine right below the water pump you will see a pee stream coming out of the bottom of the pump if the seals are bad. Also if that is not the leak you can look in other places.

The leak I stated is a common one for the 3.7's.

 

[stonyloam]

Re: Mercruiser 165, possibly water pump issue?

I may be wrong but, the engine circulating pump is driven directly by the camshaft in that engine, and my guess is that it is unlikely that it failed. If you have power steering it may have been the belt getting wet from the boil over that caused the noise. My first suspicion would be that you need to replace the impeller in the outdrive. Should be done every couple of years anyway. Once you get the impeller done running it with muffs in the driveway will allow you to track down the other problems if any. Be careful to flush away any antifreeze that leaks out, it is toxic to pets. Once you get it running again do a compression test and a cooling syatem pressure check to make sure everything else is in working order, Autozone will loan the tools for free. Good luck.