300C Crd Alternator Problem ?

[jonnyjeep]

Hi all, I have a possible problem with my alternator and really would appreciate any advice

 

After driving through alot of puddles and a few 4" - 6" floods last Friday, come Saturday morning the battery light on the dash illuminated about half a mile from home, so I turned around & went straight back.

 

Come Sunday, started car & all was fine for about 10 seconds, then battery light came on. Wipers & electric windows were slow & battery voltage (using music/compass buttons on steering wheel to display dash diagnostics) was reading 11.5 volts. After a minute or so, reading went back to normal 14.5 volts. A quick diagnostic spewed up a U1132 code - lost communication with generator. I cleared code and hoped for the best.

 

Driving around yesterday for about 20 miles and using the music/compass buttons, voltage seems to be reasonably steady displaying between 14.3 - 14.6 volts depending on electrical load. There are no more fault codes using my autel reader and my laptop 'appcardiag FCA' diagnostic software confirms that there is no problem & no more fault codes.

 

I know that alternator failure can be immediate or intermittent, in my case it may possibly be intermittent, but is there a possibility that the problem may have been caused by the amount of puddles/floods around last Friday soaking the lower engine ?....are there any connections that could have been soaked & temporarily shorted ?

 

Also, not really relevant, but possibly could be. Does anyone know what the black cylinder looking thing with two clips either side is on top of the alternator ? This thing wasn't clipped together properly on one side, but it is now

Edited February 2, 2021 by jonnyjeep

[jonnyjeep]

Well a week has passed since the battery light on & low charging issue, but all has been fine. I've done about 100 miles, but have kept the battery charge indicator on the dash diag (music & compass buttons held for a few seconds) on all the time, as things like this always make me paranoid about getting stuck somewhere.

One thing about using the dash diag, you can see what the highest electrical loads are on the car by turning wipers/lights etc on & off. I have found that the full beam headlights are by far the highest drain on the charging system, causing a drop of 0.3V.

Have also found, that if you cycle through the various settings, there is a 0-60mph timer. I haven't tried it yet...but it sounds interesting

Edited February 7, 2021 by jonnyjeep

[jonnyjeep]

Looking defo like a new alternator is on the cards.

Went out in the 300C yesterday & for the first couple of miles, charging voltage was pretty much all over the place, ranging from 12 V to 14.6V, but battery light didn't come on. Once car was warmed a little then charging settled to normal. Possibly a lazy diode ?....either way, it's defo a new alternator, as this one will obviously go completely at some point in the near future.

Replacement procedure according to the workshop manual looks a bit more than just a couple hours....more like a couple of days !. Hopefully alternator will last until weather is a little better, as I don't have a garage

 

Has anyone replaced the alternator themselves on the 300C CRD and is there an easier way of doing it, as opposed to the workshop manual method ?

 

Any replies will be greatly appreciated

Edited February 7, 2021 by jonnyjeep

[jonnyjeep]

Okay....I've learned a little more about this car since the last post.....and it seems that the voltage regulator is built within the PCM. So that means the alternator isn't really an alternator, it's just a generator....that simplifies things 

Edited February 18, 2021 by jonnyjeep

[jonnyjeep]

Alternator/generator seems to be working fine now in the warmer weather and it's happy to chuck out a good output so that the PCM internal voltage regulator can do it's job.

Not sure why it was so badly affected by sub zero temperatures, but my guess is that the brushes weren't contacting properly due to flood water getting into alternator (it's pretty low down), coupled with freezing temperatures & usual crud build up preventing the brushes from contacting.

Had a similar thing last winter on my Henry vacuum cleaner that is kept in the shed. It wouldn't work, because the brushes had seized inside their housings, due to build up of normal crud that had thickened due to moisture & the cold temperature 

Edited February 21, 2021 by jonnyjeep

[jonnyjeep]

Update time, if anyone is interested   

At cold start (now on warmer days), voltage has again started fluctuating up & down & there is now a sqeaking noise that sounds like it's coming from the alternator. After a couple of minutes, the noise goes away & voltage stabilizes.

So it's not the brushes or any weak electrical link, it's obviously the alternator bearings......so new alternator it is then

[jonnyjeep]

New Delco Remy 180 amp alternator £198 +VAT, & they require your old alternator in exchange as well    That's a shocking price for an alternator, but then again, it's a big car with a big appetite

Anyway, alternator now replaced & all seems good.

Took a couple of days at a leisurely pace with lots of tea breaks. Did the taking out from the top method as opposed to the workshop manual method (the underneath method) & it was probably alot easier & less back breaking, but probably just as time consuming.

One positive thing though about doing it from the top, is that you get to remove the throttle & it's attached plastic manifold thingy (don't know the correct name for it) & see how much oil & caked on carbon is actually in there & how much this build up of crap is actually affecting performance. I spent a bit of time cleaning all the soot & oil out & the car now seems to breath a little better & be a bit more responsive

Edited April 4, 2021 by jonnyjeep