CTYANKEE

Fellow Dieselers,

I recently purchased a 1996 E300 Diesel with 115k miles. Love the car and have a great mechanic that I trust.

While he was doing the first check up, he found a problem in starting it. It made no difference if the engine was cold or hot. It would not turn over smoothly and sometimes the "Charge Battery" light would come on. He checked the electrical system, battery, etc. and all is fine. The same thing happened while I was on vacation with the car. A local mechanic, who said he knew how to work on diesels, could not recreate the problem, but he did put in fuel conditioner ($25) and it seems to have corrected the problem, or so I thought. He did not tell me what kind of conditioner he put in.

My question is, what kind of conditioner should I put in and how often? I live in Connecticut and the diesel seems to be good, no water or junk in the tanks. This is my third MB diesel and I have never used fuel conditioner before.

Thoughts?? Thanks.

anghrist

I know that some people swear by Lubro-Moly or Liqui-Moly Deisel Hi-Test for all Mercedes diesels. I use it myself with just about every tankful. I'm not really sure that this is your problem, but I've been wrong before.

cdiken

That is about the only way an additive could fix "charge battery."

If engine idling too slow to make enough amps.

Probably and electrical issue, alternator on the way out/ voltage regulator.

CTYANKEE

A month or so ago I posted a note about problems starting my 1996 E300 D. The dash showed "Charge Battery" light. Well last weekend, not only did that "Charge Battery" light come on (in a yellow message), but the "Check Engine Electronics" light came on in Red letters. Barely got it to my indy, but left it there for a week.

The problem - The connectors for the fuel line and the fuel filters (2) had worn down. There was a significant air leak into the fuel line which was causing the problems, although it had NOTHING to do with the engine electronics.

Moral of the story - Find a good indy, diagnose, and repair properly.

Now my other question? The center air vent is not putting out heat, even though the side vents are. Getting colder here in CT. My indy says the center vent is used for AC and vents. So I shut the center vent for the winter. Is this standard on the E300's?

Xander Crews

My '95 E300D is having similar issues. Difficulty starting and power items (ex. air conditioning, radio, lighting, etc.) turning off intermittently while driving. For those of you that have experienced electrical issues, what do you suggest (other than to get looking for my volt meter)?

Edit: I also have a brand new Mercedes battery installed (at most, one month ago). I'll check the voltage this weekend.

mi benz

was the battery replaced before or after the symptoms began?

if you are having problems while the car is on then there is something wrong with your charging system or voltage regulation. this would also have an effect on the battery's performance at start-up too, of course.

I would check the voltage at the battery while the car is running. You should have around 14 volts. If not, check at the alternator output if you can get to it. if the voltage is good there, then you may have a connection issue going back to the battery.

good luck

Xander Crews

Timeline (approximate):

- 5/15/10- The previous owner put the battery on a charger. The car wouldn't start due to a long period of inactivity.

-6/1/10- I took delivery of the car and noted no issues with the car.

-6/15/10- The car had difficulty starting. Due to the earlier issue with the battery, I went ahead and replaced it.

-6/20/10- I installed an aftermarket head unit following Crutchfields instructions for dealing with W124 power wires (switch yellow and red power wires when wiring new head unit). I've installed head units before, including an identical head unit in another vehicle that same day. I don't think that is an issue, but I figured I'd just throw that out there.

-7/18/10- The car had difficulty starting AND the battery charging began to impact other electrical features (ex. A/C, lighting, radio, etc.).

A family member is the previous owner. Pretty much every accessory has been replaced (including the alternator, a "few" years ago).

I'll have to do that this weekend. Thanks for the response.

Xander Crews

The battery voltage was 13.2 with the engine off and 10.8 with the engine on. When the engine was first turned on, the voltage at the battery was higher...it started at 14.2 volts and dropped off pretty quickly to under 11.

mi benz

14.2 V is about right for the alternator output, but the voltage dropping that low doesn't look good. you should be able to go to your local autozone for an electrical system check.

i'm not sure if the voltage regulator is integral to the alternator, or if you can replace it separately.

Xander Crews

From what I've read around here...the voltage regulator is part of the alternator. I'll look into doing that.

I tried to locate 'alternator' or 'voltage regulator' in the Mercedes shop manuals (the Mercedes ones...not Chiltons, Haynes, etc.), but they're pretty thin on information. There's no index of key words and the individual sections (ex. electrical) contained no mention of 'alternator'.The Chrysler manuals for my old Jeep were far more useful/user friendly. Is there something that I'm missing with these manuals (i.e. stand on your head and read them upside down)?