Peaceful Pirate
Seaman
- Joined
- Aug 26, 2007
- Messages
- 71
Ok, now I do need help. The issue continues to be M/C 3.0/140. The initial problem noticed was oil blow-back through the dip stick. Further inspection found water in the oil AND visible water spraying out between the manifold and the head just aft of the #2 cylinder while the engine was at idle after a run on the lake. The water was spraying up out between the manifold gasket and the head/manifold, and at the same time running down the side of the block behind the manifold.
What appeared to be a small crack in the head was noticed in the general area so the initial diagnosis was a cracked head. When the engine was pulled and the oil drained, water was found in the oil filter and the pan; however, the actual oil to water ratio was very low, with the mixture showing only slight milky colorization. Also the total volume was not much more than expected on a normal oil change.
Compression test were preformed, 144, 140, 141, 137, and compression held on each cylinder. Cooling system leak-down test was done to 15 psi; however the system would not hold pressure. Pressure fell at a steady but constant rate. Recheck was done to insure external ports were closed/blocked and test redone, with the same outcome. At no time could the source of the leak be determined, though ambient noises could have contributed to this.
A replacement head was obtained off an OMC 140 and the original head was removed. No noticeable water intrusion was seen on either of the mating surfaces of the underside of the head or the top of the block, and no intrusion marks were visible on either side of the old head gasket. What was seen was what appears to be some very minor moisture intrusion in the #4 cylinder, while #1 and #2 showed similar, but not as significant moisture, possibly form sitting up (about 1 week) or when preforming cooling system leak-down.
What was thought to have been a crack in the head appears on further inspection to only be a surface blemish as there is no indication that the notice make is either a crack or the continuation of an external fracture in the head.
A review of the 3.0 cooling system adds further question in that how can water under pressure actually reach the area of the noted leak without leaving visible markings? Head gasket? Manifold gasket? Head? Block? Manifold?
I am lost!! Time for an ice tea break. As always, I do appreciate all your assistance.
What appeared to be a small crack in the head was noticed in the general area so the initial diagnosis was a cracked head. When the engine was pulled and the oil drained, water was found in the oil filter and the pan; however, the actual oil to water ratio was very low, with the mixture showing only slight milky colorization. Also the total volume was not much more than expected on a normal oil change.
Compression test were preformed, 144, 140, 141, 137, and compression held on each cylinder. Cooling system leak-down test was done to 15 psi; however the system would not hold pressure. Pressure fell at a steady but constant rate. Recheck was done to insure external ports were closed/blocked and test redone, with the same outcome. At no time could the source of the leak be determined, though ambient noises could have contributed to this.
A replacement head was obtained off an OMC 140 and the original head was removed. No noticeable water intrusion was seen on either of the mating surfaces of the underside of the head or the top of the block, and no intrusion marks were visible on either side of the old head gasket. What was seen was what appears to be some very minor moisture intrusion in the #4 cylinder, while #1 and #2 showed similar, but not as significant moisture, possibly form sitting up (about 1 week) or when preforming cooling system leak-down.
What was thought to have been a crack in the head appears on further inspection to only be a surface blemish as there is no indication that the notice make is either a crack or the continuation of an external fracture in the head.
A review of the 3.0 cooling system adds further question in that how can water under pressure actually reach the area of the noted leak without leaving visible markings? Head gasket? Manifold gasket? Head? Block? Manifold?
I am lost!! Time for an ice tea break. As always, I do appreciate all your assistance.
Last edited:
