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Time to give back to the community.
Have not seen one of these, so here is a DIY for alternator or regulator remove and replace on the R230.
hello @kbob999 - super write up here on the R230 alternator & voltage regulator replacement and THANK YOU for documenting the DIY!
I'm going to tackle this jo on my SL55 with 80k miles as neither battery seems to be charging appropriately and my BCM is fine as is my 100 amp fuse in the passenger footwell which I just painfully checked and took everything apart to do that.
Leads me to believe by charging issue must be the alternator as I did replace the voltage regulator about 6 months back and am not getting any codes at all aside from the dash red battery warning.
Quick question - you mention with a lift this is a 4 hour job, so can you remove the alternator from the bottom of the car? Or is it easier to remove from the top after you take out the fan shroud and move many of the coolant hoses?
THanks again appreciate any insights on that... thx
Thanks for the support. I love these DIY walk through projects from others too.
You cannot get the alternator out the bottom of the car without removing many parts that are even harder to remove.
Like the starter, exhaust, subframe, suspension, etc. I don't recall exactly as the car is now 2 years sold from the stable.
The biggest challenge is getting the fan and shroud out the first time (2nd time you know what to do); and squeezing the alternator through the hoses.
I did this a second time in 2 hours or less.
Good luck on your repair.
Thanks for the support. I love these DIY walk through projects from others too.
You cannot get the alternator out the bottom of the car without removing many parts that are even harder to remove.
Like the starter, exhaust, subframe, suspension, etc. I don't recall exactly as the car is now 2 years sold from the stable.
The biggest challenge is getting the fan and shroud out the first time (2nd time you know what to do); and squeezing the alternator through the hoses.
I did this a second time in 2 hours or less.
Good luck on your repair.
super helpful thanks @kbob999 am planning to try this over a weekend as I can only imagine what a pain it will be getting the fan & shroud out and stuffing that alternator through the tight space with all the hoses... but a few bloody knuckles and excessive profanity outbursts will be worth the nearly $2k the dealer quoted me for this!
Here's a bonus tip I don't think I mentioned...
Clean the hoses in front of the alternator before starting, then right before you pull the alternator - spray and wipe them with silicone lubricant.
Do the same going back in. You will be surprised how the hoses don't hang up on the alternator.
Time to give back to the community.
Have not seen one of these, so here is a DIY for alternator or regulator remove and replace on the R230.
Good day All,
Just a bit Thank You to kbob999 for taking the time to create and upload the great DIY document!
I think the SL55 has bit more things to deal with, but on a 2003 SL500 it took me about 1.5 hours to remove and replace the alternator... so overall quite painless. My only feedback would be to disconnect the two small coolant return lines at the Expansion tank. These technically do not need to be removed, but the fittings are small and fragile and if your elbow bumps or rests on them, they will break. The only other note is to take a pic of the routing of the Serpentine belt, as it is easy to forget.
As for the replacement alternator... I bought a Remy from Rockauto for about $185 with no core charge and decided to replace the serpentine belt for good measure.
Guys - quick update on my alternator replacement...
Thanks to these very helpful instructions from @kbob999 I was able to remove the radiator fan, took off the water pump dual pulleys (to get more space) and moved the coolant hoses around so I could finally remove the old alternator.
I was able to stuff the new Bosch alternator # 1986A00965 back in (purchased from FCP euro and verified fitment for SL55) got it bolted in and reconnected the clip. I attempted to connect the battery metal connector to the bolt/terminal BUT the new alternator has a different plastic cover with only 1 slot to access the bolt/terminal which the metal connector doesnt fit in. See attached photos of the old/original alternator with 2 slots and the new/bosch alternator with only one which doesnt allow the metal connector to seat properly.
I unfortunately never checked over the new alternator plastic cover to compare to the old alternator, but FCP's site said this was the correct unit and the photo on their website even shows a Bosch unit with the 2 slots.
I am considering leaving the new alternator in since its such a PITA to remove and just try to stack another nut on the alternator terminal and then attach the metal connector and tighten the top bolt down on that assuming it has good contact and should still be able to charge the battery? any issues with this?? i hate to have to remove this again and send it back to FCP for a different unit.
Original Bosch alternator with the 2 slots in the plastic housing that the battery cable slides into and connects to the bolt new Bosch alternator per FCP euro part cross-reference showing only ONE slot for the battery cable which doesnt fit the shape of the battery cable (WTF)
I would double check that the cable "seats" correctly with the electrical post, as your new alternator may cause the cable's end to be properly sandwiched between the lower nut and the extra one you will be adding. If it is OK, then I would add an oversize washer or two so that the cable end is fully contacting the upper and lower nuts. This will ensure a much larger electrical contact area. That said, double check the cable clearance now that it is now elevated.
Thanks @sam512bb i decided to just remove the plastic cover from the new alternator and swap it with the old cover which worked fine and the metal battery connection fits properly on the terminal now!
FYI - to anyone doing this repair to make sure that your alternator has the correct plastic cover or swap that out before installing the new unit
@kbob999 thank you again my new alternator is in and car is running perfect with 14+ Volts showing finally!
I would tell anybody if you have battery charging issues don’t mess around with the fuse for the battery control module start with your alternator it would save me about four or five extra hours of screwing around.
New alternator in and finally showing correct 14V charge
Thanks @sam512bb i decided to just remove the plastic cover from the new alternator and swap it with the old cover which worked fine and the metal battery connection fits properly on the terminal now!
FYI - to anyone doing this repair to make sure that your alternator has the correct plastic cover or swap that out before installing the new unit
@kbob999 thank you again my new alternator is in and car is running perfect with 14+ Volts showing finally!
I would tell anybody if you have battery charging issues don’t mess around with the fuse for the battery control module start with your alternator it would save me about four or five extra hours of screwing around. New alternator in and finally showing correct 14V charge
Good day again jvakos,
That is great news and some excellent comments. Beware that even if the alternator is producing enough voltage (e.g. > 14 V), that it can still be faulty. The output voltage is one thing, but the alternator must also supply current to the battery in order to keep it charged up. On my car, the output voltage was 14.25V, but could not maintain the battery's charge and so after a few weeks the low voltage battery voltage would appear. Also, be aware that the battery system is critical to the operation of the brake system... a very low battery can affect braking... a lot.
That said, given the low charging current by the alternator, I thought it best and easiest to change the alternator... and now all is working properly.
Thanks @sam512bb good point about double checking the battery charging despite the 14V showing on the dash.
I absolutely love this SL55 when it’s working but I swear I was ready to dump her after getting fed up with the bloody ABC issues and electrical issues.
Glad I stayed patient and did the Silvers coil over swap and finally have this electrical / battery issue solved and $5k later she’s running amazing and puts smiles on my face.
Now if I could only get my 996TT cab out of the shop and have that ready for summer too I’d be ecstatic!!
I am definitely grateful for all the help on these forums to keep our cars running!
Thanks @sam512bb good point about double checking the battery charging despite the 14V showing on the dash.
I absolutely love this SL55 when it’s working but I swear I was ready to dump her after getting fed up with the bloody ABC issues and electrical issues.
Glad I stayed patient and did the Silvers coil over swap and finally have this electrical / battery issue solved and $5k later she’s running amazing and puts smiles on my face.
Now if I could only get my 996TT cab out of the shop and have that ready for summer too I’d be ecstatic!!
I am definitely grateful for all the help on these forums to keep our cars running!
Good day jvakos,
You are most welcome and indeed, thanks to everyone on the site for their assistance! It is help from everyone that allows us to maintain and enjoy our cars! One could always go to a dealer, but not all dealers are the same in terms of skills and cost and so if one can dig in and DIY, then it makes owning one of these cars much easier... on the pocket book too!
My ABC system is still working fine... so far... but have no issue with going with the coil overs should something nasty arise. My only major concern/complaint is the braking system and that it is highly dependent on the electrical system. I do not know if it is the same on the SL55, but on the SL500 (2003)... if battery is low enough (in my case 11.73V), my brake pedal goes right to the floor, the dash lights go crazy (basically flashing you are going to die), and braking level drops by 95-98%! Driving along and losing brakes is not an experience one wants to have. To me this an epic fail and concern... so when driving... just be aware that this can happen and to plan on taking countermeasures if possible.
Enjoy your cars in excellent health and I hope you get your 996 all sorted!
07-27-2015, 03:39 PM
