Trojan Boat Forum

My engine is making a horrible squealing sound when I rev the engine beyond an idle. It sounds like it is mostly coming from the front of the engine. I can feel water rushing into the thermostat housing and out to the exhause manifolds. I did replace the thermostat with one I purchased at West Marine. The flange was slightly smaller than the original one that was in there but it seemed to cover the hole and the gasket sealed. Any ideas. I have some suspicions but I want to her what you guys think my problem is.

Belts, raw water pump, circ pump, alternator.

Check your belts, they should be riding just above the top of the pullys and have about an inch of slack when pushing and pulling on them between the pullys

yep, check belts. i just replaced the port raw water pump and had same issue....good at idle but when revved squealed, tightened belts and all is good.............John

When my raw water pump impeller failed on the port engine the water pump locked up and the belt started squeeling, there was no water flow out the exhaust, so a week later when I heard the stbd belt start squeeling, sure enough the pump was locked up and no water flow coming out the exhaust. When the port pump failed, I bought 2 rebuild kits and I'm glad I had the other one on board when the stbd side failed, on the water, 50 miles from home.

The belts seem to be right tension and riding properly. I have seen lots of squeaky belt on old cars, but this sqeal sounds, well, I guess the best way to describe would be more gutteral...if that makes sense.

If the pump is failed would I feel water flowing into the Thermostat housing? I do now recall when I had it on the hard I would start it and it would get that sound, but once I turned on the water hose and fed in some water it went away. Could the water pressure from the house hose have been feeding it enough water, but not the pump by itself?

This is what a water pump impeller looks like after it fails. You can see that the broken impeller pieces can get jammed and brake the water jackets of the pump and stop the pulley from turning. The impeller needs replaced before running the engine.

and this is what the impeller should look like. This particular Mercruiser repair kit replaces the impeller housing, plate and end cap with a one piece housing.

You can do a search on here for "impeller" and find more info.

This is the raw water pump that cools the exhaust and trans oil. This is the water that comes out the exhaust pipe while the engine is running.

Well I guess I will be spending some time pulling off the water pump. Anmy tips for removing it? The engine is pretty close to that bulkhead there so do I need to hire a contortionist to reach down into there.

What motor do you have?

Chrysler 318

Wowser's are down low, yours are close to the top at the front on the port side of engine (balancer facing bow). It may not be that bad. These can be tricky; mark everything so you put it back together properly. They can be reversed if not carefull and will pump the wrong way. FWC or RWC? Do you have a circ pump? Asking because some applications used dual pocket pumps (two impellers). Single pocket will have two hoses, dual pocket will have four.

Last night as I was trying to locate the sqealing I was running the engine about 2000 rpm checking belt movement and feeling the water pressure in the hoses and the sqealing slowly dissappeared.

I was thinking maybe I just had not run it long enough at higher RPM since I had only idled it will on the hard with the garden hose attached.

Did you check the ater flow out the exhaust?