Battery Warning light - Water Pump/V-Belt

[honey1]

My C180 Elegance Feb 1997 - water pump ceased up.

Just had it replaced yesterday and a new V Belt fitted - and now the battery warning light comes on for 3 minutes after starting , and then intermittantly when driving for a few seconds, every 10 mins or so.

Garage say V-Belt is auto tensioning.

I live 40 miles from garage so its not easy to drop back in to get it checked .

Any simple ideas what may be wrong?

Anything I could try and look at myself?

 

[jberks]

Intermittent warning light sounds more like a bad connection somewhere. Possibly they haven't tightened up a earth or something.

Check the wiring at the back of the alternator and generally in the engine bay and also the battery connections, though I'd imagine you'd have starting problems if they'd left those loose.

I can't see how the tensioner could have anything to do with it. Who did it and if it's who I think it is, who told you it was the tensioner?

 

[television]

Sounds to me like the belt or auto tensioner is incorrectly fitted, if the alternator was OK before.

Malcolm

 

[honey1]

SOrry maybe I explained it wrong - No one told me that it WAS the tensioner - I just suspected that the battery was not being charged, or was being drained staight after starting and then maybe whenever the battery came under pressure , the warning light flicked on again -

so I suggested that maybe the belt might need tightening and asked the garage over the phone if this might be so

[ They are a merc specialist but not a main dealer ]

- they said no as the tensioner was automatic.

I dont think it IS a lose wire but will see what I can find - what does the alternator look like and where is it?
and thanks for the suggestion.

- I think the suggestion that the auto -tensioner or belt fitting itself needing adjusting - if you say this is a possibility - sounds quite likely from my symptoms. Thanks for that.

Suppose I will have to take it back in to them - and just pray that its not an alternator fault as well.. How would I check if the alternator is wonky?

Meanwhile - any other suggestions equally welcome........

 

[television]

I will answer later in the day. must walk down to the sea and have a coffee.

Malcolm

 

[turnipsock]

If it's anything like the older cars, then the auto tensioner still needs adjusted first. The auto tensioner keeps an even pressure on the belt but you still have to adjust it to a position first.

Are other things like the power steering still working?

The biggest load on the alternator happens just after the car starts so there is a big load on the alternator then. You sometimes see people with loose belts turning on their lights and the belt starts screeching.

You should be able to see if there is a reasonable tension in the belt.

If it wasn't a merc dealer/specialist then there is a chance that they have routed the belt incorrectly.

 

[kth286]

honey1

I tensioner on your year car should be automatically self adjusting.

It is on my late 1995 3.2 litre W124 coupe - no pre adjusting required - just fully automatic.

I replaced my own water pump (not a job for the faint hearted) and put the new poly belt on, and hey presto, fully working for the last umpteen thousand miles.

Regards

 

[C220GJS]

As kth286 says the belt on the C180 is self adjusting, the belt tensioner is spring loaded and there is no facility for manual adjustment.

 

[television]

If the light (not charging) only comes on now and then, the first thing to do is to start the car and turn the headlamps on,does the lamp come on,rev the engine up,does the light stay on and or do the headlights go brighter. if the headlight do not get brighter and the light stays on the chances are that one of the diodes has gone, it is very quick to change the diode regulator pack. there is a certain order for which of the four has gone, but it really does not matter in this case as they all have to be replaced as a pack.

Malcolm

 

[turnipsock]

As kth286 says the belt on the C180 is self adjusting, the belt tensioner is spring loaded and there is no facility for manual adjustment.

okay okay, I stand corrected.

I also did the water pump on my 93 320CE and there is an adjuster on that. It's the same setup as my 230TE. It's a helpful thing to get the belt on.

 

[television]

I also did the water pump on my 93 320CE and there is an adjuster on that. It's the same setup as my 230TE. It's a helpful thing to get the belt on.

Sadly nothing becomes easier, lots of good idea's have sailed into the wind, all for the greed of motor car makers who want to make it as hard as possible to do it yourself.

malcolm

 

[jberks]

With no mention of squealing, plus the intermittent nature of the fault, plus I suspect if the belt was worn, they would have replaced it, I still suspect the alternator or a connection. I'm pretty sure the tensioner is fully automatic and it doesn't 'bed in' as such so whatever the fault, it isn't going to get better without intervention.

 

[honey1]

Thanks Guys for all the advice and information so far.

Particularly Malcolm for the headlights revving test – I have printed that off for future reference as it seems an easy to follow useful test to do when needed.

BUT - MY PROBLEM SEEMS SOLVED Hurray...

I laughed my socks off when I discovered the answer.......

Not sure if I should tell you....


But feel its only fair................ and maybe you deserve a chuckle as well....

I decided to ring the garage again to book the car in to be looked at
– and they said
– just on the off chance ............... is the battery warning light yellow?

When I said yes – they said – well that light does LOOK like a battery
but actually its a radiator............................

Well.............

[ apparently the battery light is RED ] not unlike my face just then !!!!!

Diagnosis – air lock in water system when refilled after water pump fitted.
Just needs topping up.

I did this [took about a pint ] - no lights on since – radiator or battery shaped!!!!

 

[television]

So pleased the car is fine, that's the important bit, good luck.

malcolm

 

[jberks]

aaahh - we all live and learn!

 

[kth286]

thanks for the smile honey.