6 months old alternator gone bad?

[fangio_gg]

Hi forum, just cared to share the story of my new alternator that seems to have gone bad. I don't often drive my W201 in the rain, but I was in a hurry so I went. The car been stood outside summer, winter and seasons most of it's life from previous owner but I tuck it way from wet and moist. It is exposed to outside temperatures though. But dry.

So I went for a drive 10 minutes max and I had this burning electronics smell as I was about to park. Also realized all my cluster and dash warning lights lit up. And they stayed lit as I drove home. Car runs good, looks like a Christmas tree in the dash. Disconnected battery a few hours, still all dash warning lights on. As you usually get in these circumstances.

I measured 11,92v dc on my multimeter from each battery terminal with the engine running. Steadily dropping as the engine kept running. As if it wasn't charging. It had this weird behavior sometimes dropping to 0 every now and then. Then I measured on the positive connector on the alternator used engine block just next to it as ground. It was about the same 11,5 something which I had from the battery, sometimes jumping like showing 0 but more frequent then on the battery and it even read negative values. Just odd. I just disconnected everything when I left to be sure.

The alternator is non OE but should reassemble part number 0081549602 / 009 154 41 02:
Volt (V) 12
Generator-charge (A) 70
Engine code M 102.910

The alternator was a good €150 I guess chances are this is what happens when you go aftermarket. I'm very sure I didn't hit a puddle big enough to fry anything since I've driven in worse conditions without this occurring. Just order a new one?

 

[rayhennig]

Was it a remanufactured alternator? If so, who did it - a reputable company? I've just replaced alternator and starter motor with Bosch remanufactured parts. So far so good.

RayH

 

[ajlsl600]

Regulator fried.? Contact supplier before opening anything

 

[peterws1957]

I would suspect a faulty replacement alternator as well. I would also double check to verify that the correct alternator was supplied.

 

[fangio_gg]

Alternator was new albeit not premium, I was under the impression it was not a refurbished/remanufactured piece but then, who knows. Opened a recall case with the shop, it is a well known here in Scandinavia. And they emphasize that if it really is faulty I’d have a choice of getting a replacement one or money back even if it wasn’t a certified mechanic who made the installation.

I want a running car so I’ll just have a new one ordered in the meantime. I’d be happier if something else broke that had not been changed

 

[mioba]

Mercs dont like substandard parts fitted. Assuming you changed the original which lasted near on 30 years which goes to show the quality.
Lets hope nothing else got damaged.
Did you try your local dealer for a new one. You may be surprised at the price as there may well be NOS in the network.
good luck and keep us posted

 

[fangio_gg]

Received my new alternator yesterday, was fitted in 10 minutes and I now have charge. Battery showed 13.5 volt with the car running. The dash warning lights went away as well.

It was raining yesterday, took it for a drive. When I got back I opened the hood up to see if the engine bay was moist somehow or the alternator. Since it sits close to the exposed exhaust manifold the alternator was really hot. Coulnd’t really put my hand on it. Dry and very hot. Could that inpact alternator lifespan, read about other brands that had similar issues but on different components.

Does your cars have a heatshield?

Edit: Also added extra ground strap from engine to chassis and put battery grease on mounting points/bolts of the alternator. If its a ground thing.

 

[LostKiwi]

Fitting a heat shield will do no harm.

 

[mioba]

Depending on the quality of the replacement then the heat will have an influence.
A higher temp will increase the resistance and the overall efficiency of the alternator.
Things like this will be more pronounced in aftermarket (cheaper) which will may not factor in what merc realised when putting the car together.

 

[fangio_gg]

Bit of an update. I ordered a new one but think I was a fool to order the same piece again. Only this 2nd one lasted for a mere 2 months. Car is chewing up these alternators. Before I changed I made sure to replace some of the wires and heavy cables coming to and from the alternator and battery. Brand new battery is in as well. I think the original Bosch one had sat there a good time when it broke in May. Going to end up ordering a 3rd piece.

I also think the dashboard lights changed when turning the ignition key. The lot showed up before, now I just get ABS. I read something funny about a simple battery/alternator bulb and if bad won't tell the alternator to start doing its thing creating volts. But I'm not sure if that applies to the W201.

 

[bembo449]

I reckon a 2nd hand one would last longer than that

 

[EmilysDad]

I wonder if there's an under lying fault on the car that's killing the alternators

 

[bembo449]

13. summat Volts seems low for a fully function olly pal , most ive worked on are 14. summat

 

[ajlsl600]

Some fault fryin regulator??

 

[Kev555]

I think if it was me i would book it in with local autospark and get him to check everything out and fit the new alternator?

 

[mioba]

13v way to low, thats like constantly filling a leaking bucket.
You mention - you replaced some of the wires and heavy cables coming to and from the alternator - were these the right spec cables - can they handle the current. were the originals even goosed.

 

[fangio_gg]

I pealed the cover away on some cables and found the common white/green mushy corrosion. At first glance the cables looked alright, but not underneath. Went with 16mm cables and I'm not runny any grand accessories.

Wondering if there is some perfect storm with the previous alternator working overtime failing due to bad lines and this new one actually was bad itself. Just 2 months and I don't even drive much. There's also the scenario because I didn't change battery the same time I changed the recent alternator, that the old battery was bad and killed it. I haven't driven the car very much on this new battery, so till I receive my Bosch alternator I pulled it out. Followed the wires over and over again, have great respect for electrical gremlins.

Obviously something fishy been going on, just need to dig in even more if there is something missed in need of care. What I haven't yet done is to run extra ground from the alternator housing to chassis. And replacing rest of the car's old parts with new ones Still think it's the Merc's way saying Merry Christmas getting attention.

 

[ajlsl600]

I put a new batt on clk once. Because I did not know trick of having load ,lights ect on at first new start when I did start it it blew regulator on alt. Changed reg .that was 10 yr ago .no issues with that since