DeepBlue2010
Lieutenant
- Joined
- Aug 19, 2010
- Messages
- 1,305
Hi,
Last week, I had to replace my water pump on my Mercruiser 7.4 Bravo III. As you know, the water pump is attached to the engine block. The impeller was in shreds so I had to reverse flush the system to get rid of the pieces. For that, I disconnected my oil cooler from the heat exchanger; disconnect the upper oil line (coming from the remote oil filter) from the cooler so I can move it free. Then, I put a water hose in the loose end of the cooler (the upper end that was attached to the heat exchanger) and flushed the system. The small pieces came out of the other end of the system (The hose that connects to the water pump) but there is no way to tell if I got them all. Shortly after, everything was back together and the engine running nice and cool. This was Saturday 08/04. On Sunday 08/05, I took her out the whole day and everything was fine. On Saturday the 11[SUP]th[/SUP], I took her out for few hours and everything was working perfect. Yesterday, Sunday the 12[SUP]th[/SUP], while I am warming up the engine and after about, say 15 minutes mostly on idle or very low RPM, my sound alarm kept going on and off and my oil pressure gauge is at zero with few spikes to 20 for no more than 2 seconds (since I start monitoring anyway). The engine temp did not increase. I returned back to the dock, took about 5-10 minutes, and turned off the engine. When I opened the engine hatch, the oil was splashed everywhere and ended up in the bilge. The splash patterns indicated that the oil is leaking on top of the belts. I pumped out whatever left of the oil inside the engine which was not much at all (the pump was able to get out about a quart ? with no sealed and tight connection to the threaded end of the dip stick - with no signs of water in it. After adding oil (1.5 Gallons to the full mark on the dip stick) first thing I checked is the oil filter hose I disconnected from the oil cooler during the water pump replacement, and this was it. The hose was leaking but not from the bolted connection, it was leaking from the metal brace on top of this.
I will try to find a replacement for this hose but this is the least of my worries now. I am so concerned that the engine ran few minutes with very little oil and very low oil pressure. My math says that there were about 3-4 quarts left in the block (Total oil capacity = 8 quarts). Questions time for the experts..
Last week, I had to replace my water pump on my Mercruiser 7.4 Bravo III. As you know, the water pump is attached to the engine block. The impeller was in shreds so I had to reverse flush the system to get rid of the pieces. For that, I disconnected my oil cooler from the heat exchanger; disconnect the upper oil line (coming from the remote oil filter) from the cooler so I can move it free. Then, I put a water hose in the loose end of the cooler (the upper end that was attached to the heat exchanger) and flushed the system. The small pieces came out of the other end of the system (The hose that connects to the water pump) but there is no way to tell if I got them all. Shortly after, everything was back together and the engine running nice and cool. This was Saturday 08/04. On Sunday 08/05, I took her out the whole day and everything was fine. On Saturday the 11[SUP]th[/SUP], I took her out for few hours and everything was working perfect. Yesterday, Sunday the 12[SUP]th[/SUP], while I am warming up the engine and after about, say 15 minutes mostly on idle or very low RPM, my sound alarm kept going on and off and my oil pressure gauge is at zero with few spikes to 20 for no more than 2 seconds (since I start monitoring anyway). The engine temp did not increase. I returned back to the dock, took about 5-10 minutes, and turned off the engine. When I opened the engine hatch, the oil was splashed everywhere and ended up in the bilge. The splash patterns indicated that the oil is leaking on top of the belts. I pumped out whatever left of the oil inside the engine which was not much at all (the pump was able to get out about a quart ? with no sealed and tight connection to the threaded end of the dip stick - with no signs of water in it. After adding oil (1.5 Gallons to the full mark on the dip stick) first thing I checked is the oil filter hose I disconnected from the oil cooler during the water pump replacement, and this was it. The hose was leaking but not from the bolted connection, it was leaking from the metal brace on top of this.
I will try to find a replacement for this hose but this is the least of my worries now. I am so concerned that the engine ran few minutes with very little oil and very low oil pressure. My math says that there were about 3-4 quarts left in the block (Total oil capacity = 8 quarts). Questions time for the experts..
- What symptoms of oil starvation I should be in the lookout for?
- Do you guys think that the engine might have suffered an irreversible damage? How can I tell?
- Can any of the impeller pieces cause the oil pressure to increase to the point that it start leaking out?
- Why my fuel pump did not disconnect due to the low oil pressure? My understanding is that it should have disconnected, am I correct?
