98 626 generator issue - pulling my hair out
#1
12-24-2007, 02:53 PM
98 626 generator issue - pulling my hair out
My son's 98 626 (4 cyl) has developed a recurring problem with the generator belt and the generator itself. The belt squeals badly, not all the time, but a lot. But it also wears out quickly; I have had to replace the belt several times, and have also had to replace the generator itself a few times. And that is no easy job. (Neither is the belt, for that matter, but I have done it so many times that I can just about do it in my sleep now.)
When the squealing does occur, I have disconnected the positive battery cable, and the squealing stops, and the engine runs smoothly. I replace the battery connector and it's obvious that there is then a load on the engine; the squealing starts, and the engine idle speed slows considerably, as if it had been put in gear with the brake on.
Eventually the generator itself wears out. (No duh there, since there is clearly an overload of some kind on its output.) This is usually indicated by the battery light coming on, even though the belt is on and running. When this happens, too, the squealing stops, but obviously the battery is then not being charged.
The last time I replaced the generator I got a salvaged one instead of a rebuilt one, because I had a similar problem years ago with rebuilt starters on an old Mustang of mine (I had to replace it several times until I got an OEM from the salvage yard, and it ran great for a long time afterward). I figured that this generator problem was a similar issue, but it didn't help.
This last time I replaced even the battery itself because I reasoned that the old battery may have developed an intermittent shorting cell -- if that's possible -- thus placing an extra load on the generator when charging. But that hasn't fixed it either.
I am wondering now if there is a sticking relay, or something like that,that might be placing an extra load on the charging system. As I said, it's intermittent, it doesn't always do it. For example, he tells me that last night he drove it to a store about a mile away, and it squealed the whole way there. But on the way home it didn't squeal at all. This was right after I replced the belt and put in the new battery, and I test-drove it and it seemed fine.
By the way, the most trusted automotive shop I know was not able to fix the problem either, though they thought it was fixed, only to have it start up again.
I am not seeing any other issues with this car that would give me a clue. At my age, what little hair I have left is very important to me.
Surely this is an issue that others have faced! Any help from a wise engine expert would really be appreciated!
When the squealing does occur, I have disconnected the positive battery cable, and the squealing stops, and the engine runs smoothly. I replace the battery connector and it's obvious that there is then a load on the engine; the squealing starts, and the engine idle speed slows considerably, as if it had been put in gear with the brake on.
Eventually the generator itself wears out. (No duh there, since there is clearly an overload of some kind on its output.) This is usually indicated by the battery light coming on, even though the belt is on and running. When this happens, too, the squealing stops, but obviously the battery is then not being charged.
The last time I replaced the generator I got a salvaged one instead of a rebuilt one, because I had a similar problem years ago with rebuilt starters on an old Mustang of mine (I had to replace it several times until I got an OEM from the salvage yard, and it ran great for a long time afterward). I figured that this generator problem was a similar issue, but it didn't help.
This last time I replaced even the battery itself because I reasoned that the old battery may have developed an intermittent shorting cell -- if that's possible -- thus placing an extra load on the generator when charging. But that hasn't fixed it either.
I am wondering now if there is a sticking relay, or something like that,that might be placing an extra load on the charging system. As I said, it's intermittent, it doesn't always do it. For example, he tells me that last night he drove it to a store about a mile away, and it squealed the whole way there. But on the way home it didn't squeal at all. This was right after I replced the belt and put in the new battery, and I test-drove it and it seemed fine.
By the way, the most trusted automotive shop I know was not able to fix the problem either, though they thought it was fixed, only to have it start up again.
I am not seeing any other issues with this car that would give me a clue. At my age, what little hair I have left is very important to me.
Surely this is an issue that others have faced! Any help from a wise engine expert would really be appreciated!
#2
12-24-2007, 03:46 PM
RE: 98 626 generator issue - pulling my hair out
Well, as is often the case for me, no sooner do I commit to facts as I know them than something changes. I need to change a few things to clarify the previous message.
Right after I wrote my earlier message I went back out and began to poke into other areas of the electrical system. I began to notice, while the engine was idling, that when the electric cooling fans come on, the engine slows down as if there is a load, and the squealing starts very lightly (at idle, the squealing is only barely there). Both fans come on and seem to be running ok, but when they do come on, the voltage at the battery dips from 14.7 or so to below 12 volts, only briefly, and then rises again, but not up to the full 14.7 volts. Not until the fans shut off again.
So I opened the fuse box and started pulling fuses. The fuse marked "AD fan," when removed, stopped the load on the engine; meaning that the squealing backed off and the engine returned to normal idle. One of the fans shut off, the other kept running. The fuse marked "cooling fan" shut off the other fan, but made little or no difference to the load of the engine when pulled.
Both fans seem to be working all right -- they are running as near as I can tell at full speed. But could there still be a problem with a fan even if it appears to be running all right?
As an experiement I have left the AD fan fuse out. I drove it for a while and heard no squealing, and saw no threat of overheating. Being winter, I don't expect that to be an issue, but I have instructed my son to keep an eye oncoolant temp guage. If the squealing does not return, I think we have our solution.
Does anyone have any thoughts about this?
Thanks!
Right after I wrote my earlier message I went back out and began to poke into other areas of the electrical system. I began to notice, while the engine was idling, that when the electric cooling fans come on, the engine slows down as if there is a load, and the squealing starts very lightly (at idle, the squealing is only barely there). Both fans come on and seem to be running ok, but when they do come on, the voltage at the battery dips from 14.7 or so to below 12 volts, only briefly, and then rises again, but not up to the full 14.7 volts. Not until the fans shut off again.
So I opened the fuse box and started pulling fuses. The fuse marked "AD fan," when removed, stopped the load on the engine; meaning that the squealing backed off and the engine returned to normal idle. One of the fans shut off, the other kept running. The fuse marked "cooling fan" shut off the other fan, but made little or no difference to the load of the engine when pulled.
Both fans seem to be working all right -- they are running as near as I can tell at full speed. But could there still be a problem with a fan even if it appears to be running all right?
As an experiement I have left the AD fan fuse out. I drove it for a while and heard no squealing, and saw no threat of overheating. Being winter, I don't expect that to be an issue, but I have instructed my son to keep an eye oncoolant temp guage. If the squealing does not return, I think we have our solution.
Does anyone have any thoughts about this?
Thanks!
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