This is a 2004 Merc 5.0 MPI, with 250 total hours. The dealer has put it on the computer and can find nothing wrong.
The noise sounds like a car pinging on bad gas going uphill. Not the gas; been using 92 octane ETOH free. The raw water pump has about 70 hours on it, the rest of the stuff run by the serpentine belt is original. Initially it was only about 3500 RPM on cruise that the noise was present. Now, it comes in as low as 1800 and increases with RPM.
New serpentine belt, new idler pulleys (2). Have listened with stethescope and cannot locate the noise. Took off serpentine belt after first checking that the noise was still present, it was not. Therefore it is in one of the items run by that belt. The water pump pulley is tight without wobble, no apparent leakage from main pump. Raw water pump is solid, no play other than impeller resistance, smooth to turn. Alternator is tight, no play in alternator or pulley. Crank pulley is fine.
But the power steering pump has fore aft play of 1/8-1/4 (did not measure, was a feel thing) and it seemed a bit much from what I remember of the old delco pumps which is what this looks like. Power steering is working fine, fluid normal.
Interestingly, after re-installing the belt the noise was almost gone, and thinking back this happened before when I did the idlers, I thought the problem was resolved....NOT.
So at this point, I have positively determined it is not the timing, it is definitely run by the serpentine belt. This makes it more an annoyance than a critical issue.
NOW my questions are: Is this normal play for the PS pump? What is acceptable, I cannot find specs. Has anyone else experienced this? A different forum and I did not agree with each other. But one person did mention they felt the alternator would be the culprit and one would not be able to feel the bad bearings in the alt.
I am retired. I was an automotive mechanic for 20 of my younger years, do machining and stuff for play now, so I am pretty competent. I do not want to just throw parts at it, I want to KNOW what it is. I understand I can match the pump to an automotive one and it doesn't violate USCG regs. If alternator, I can rebuild that, if Pump I hear not a good idea to try that.
I hope I have not led anyone down a stupid road, like one post on the other site that told me to flush the PS pump. That sure as heck isn't going to change the play. At this point I am not even sure how much play there should be.
Thanks
Jack
The noise sounds like a car pinging on bad gas going uphill. Not the gas; been using 92 octane ETOH free. The raw water pump has about 70 hours on it, the rest of the stuff run by the serpentine belt is original. Initially it was only about 3500 RPM on cruise that the noise was present. Now, it comes in as low as 1800 and increases with RPM.
New serpentine belt, new idler pulleys (2). Have listened with stethescope and cannot locate the noise. Took off serpentine belt after first checking that the noise was still present, it was not. Therefore it is in one of the items run by that belt. The water pump pulley is tight without wobble, no apparent leakage from main pump. Raw water pump is solid, no play other than impeller resistance, smooth to turn. Alternator is tight, no play in alternator or pulley. Crank pulley is fine.
But the power steering pump has fore aft play of 1/8-1/4 (did not measure, was a feel thing) and it seemed a bit much from what I remember of the old delco pumps which is what this looks like. Power steering is working fine, fluid normal.
Interestingly, after re-installing the belt the noise was almost gone, and thinking back this happened before when I did the idlers, I thought the problem was resolved....NOT.
So at this point, I have positively determined it is not the timing, it is definitely run by the serpentine belt. This makes it more an annoyance than a critical issue.
NOW my questions are: Is this normal play for the PS pump? What is acceptable, I cannot find specs. Has anyone else experienced this? A different forum and I did not agree with each other. But one person did mention they felt the alternator would be the culprit and one would not be able to feel the bad bearings in the alt.
I am retired. I was an automotive mechanic for 20 of my younger years, do machining and stuff for play now, so I am pretty competent. I do not want to just throw parts at it, I want to KNOW what it is. I understand I can match the pump to an automotive one and it doesn't violate USCG regs. If alternator, I can rebuild that, if Pump I hear not a good idea to try that.
I hope I have not led anyone down a stupid road, like one post on the other site that told me to flush the PS pump. That sure as heck isn't going to change the play. At this point I am not even sure how much play there should be.
Thanks
Jack
