What would cause this? Take a look.
06-24-2005, 05:24 AM
#1
What would cause this? Take a look.
I recently bought a low mileage Pathfinder VQ35 from Southpoint Nissan (where DAVEB works). It was pulled out of a PF because it was making a noise, and they opted to just replace the motor rather than spend time diagnosing and fixing the problem. DAVEB thought that maybe it ingested a screw. So I got it real cheap, although it was still a bit of a gamble.
I took it apart this week and found absolutely no cylinder head, piston or cylinder wall damage. But when I pulled the water pump, there were tiny metal flecks on the coolant side of the pump and all inside the coolant passage behind the pump. The metal flecks are not magnetic, so I think they are aluminum. The water pump seems to be fine without excessive play or binding. Fortunately there are no flecks in the oil at all. There is no sign of coolant in the oil, and no oil in the coolant.
I can't think of anything that would cause this except a bad water pump, but it looks okay. Or possibly a radiator leak that was temporarily fixed with the stuff that has aluminum particles in it. But why would they then have to replace the engine? There is no sign of overheating and the head gaskets look fine. The internals look absolutely normal and very low mileage.
I took it apart this week and found absolutely no cylinder head, piston or cylinder wall damage. But when I pulled the water pump, there were tiny metal flecks on the coolant side of the pump and all inside the coolant passage behind the pump. The metal flecks are not magnetic, so I think they are aluminum. The water pump seems to be fine without excessive play or binding. Fortunately there are no flecks in the oil at all. There is no sign of coolant in the oil, and no oil in the coolant.
I can't think of anything that would cause this except a bad water pump, but it looks okay. Or possibly a radiator leak that was temporarily fixed with the stuff that has aluminum particles in it. But why would they then have to replace the engine? There is no sign of overheating and the head gaskets look fine. The internals look absolutely normal and very low mileage.
06-24-2005, 09:49 AM
#3
The pump might look fine outside, try spinning it and listen for metalic grinding/ feel for some kind of uneven drag. If that metallic crap is inside its possible the internal bearing(s) of the pump was defective from factory and the residue from that got into the coolant. But I doubt that'd make anywhere as much material as I get the impression you say you found. It is possible that they used that Aluminum powder sealer to seal a crack in the radiator like previously said.
If you say that there is no sign of overheating damage, the head gasket is in good condition, and its just that stuff in the coolant passages, those are the only options I can think of.
If you say that there is no sign of overheating damage, the head gasket is in good condition, and its just that stuff in the coolant passages, those are the only options I can think of.
06-24-2005, 04:32 PM
#4
It does look like they put stop-leak in the thing. But you're probably going to replace the waterpump anyway.
You could also check the ph level of whatever coolant is left in the block. Caustic mixtures of AF tend to eat away at aluminum. Saturn knows this all too well.
Without a good description of the noise or hearing it for myself I am at a loss as to what it would have been.
You could also check the ph level of whatever coolant is left in the block. Caustic mixtures of AF tend to eat away at aluminum. Saturn knows this all too well.
Without a good description of the noise or hearing it for myself I am at a loss as to what it would have been.
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