I have a Mercedes SL500
, which I owned for two years now. When I bought it, there were evident signs that the front battery
and possibly the rear too, had previously exploded before I bought the car, indicating gross overcharging. I was always suspiious about the charging system until recently, I had to replace the rear battery which my electrician said I "boiled over". A few days later, the smell of burning was evident and the dash reading told me to go to the nearest electrician. Result completely burnt regulator. A new one was installed and system checked. Less than a week later, while driving, the smell of boiling sulphuric acid indicated to me the battery was over-charging and very hot to the touch. For me this could be faulty earths, but it could mean much more. Other Merc 500 owners have had similar faults. I don't want to burn my alternator
, or battery, or sell the car. Could weak earth connections (as these cars are notorious for rusting) be the cause of the problems? If I drive very slowly, nothing much happens which I notice, but as soon as I raise the revs for a VERY SHORY WHILE, maybe 30 seconds, I already feel the smell of overcharging. When these happened, I had nothing on, no radio, no headlamps, but the AC was on in both cases. Can you help please? ANTON Malta.
JA: Battery issues can be tough to diagnose - lots of things to consider. Luckily, the mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself? No, I use streaming services like Pandora.
Customer: I have worked on cars for thirty years or so, mostly preparation for racing, that is after first qualifying in electronics. Unfortunately now I am too old to "get out and get under" as in the old days. I have tipped my electricians about this problem of weak earths, but they seem to want to think that they are wiser than me.
JA: Is there anything else the Mercedes Mechanic should be aware of about your Mercedes?
Customer: No, not really. Once it was caught in a flood, but since complete dismantling and drying out literally every nut and bolt, it has worked fine, only that as I mentioned earlier, on being driven on the highway, the starting battery literally exploded, but that was before the flood. No problems after until a few months ago. This happened as it was driven overland from England to Malta.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and then connect you two.