Car warranty

juicylucywb

I bought a used car just under 3 months ago and I have had a warning light come on which apparently means the alternator has gone. I contacted the garage where I bought it and have been told that by my description they guess it's a worn belt which would be a consumable, like tyres or breaks etc. I have no information on the warranty, it's just written on the invoice that I have 3 months warranty. 
Does anyone know if this should be covered under the warranty? The car is 13 years old,.so surely it was pre existing? Any advice great fully received! 

Ayr_Rage

Drive belts are wear and tear items, especially on ancient vehicles, if that is the actual fault.

Is there any history as to when it was last replaced, it should've had several at that age.

Alternators either work or they don't, it won't be a pre-existing fault if it was working normally for the last 13 or so years if it is the original part.

Your best bet it to take it back to the garage, get a confirmed diagnosis of the issue and go from there.

3 month warranties are usually worth little more than the paper they are written on, prepare yourself for the repair bill coming your way and take any contribution from the garage or warranty provider as an unexpected bonus.

Mildly_Miffed

The belt that drives the alternator drives other things, too - perhaps power steering, perhaps coolant, perhaps aircon - depending on the car.

If the belt snaps, then that will indeed cause the lack-of-charge ("battery") light to come on. The belt should be a service consumable, replaced periodically according to wear.

But after 13 years... the alternator may simply have retired.

Warranties never cover wear and tear.

inthedepthsofthesea

Could it just be that the battery is too old? I thought I had an alternator problem once, but turns out the battery was just so old it couldn't hold a charge any more.

paul_c123

By your own admission, the light has just come on, so the likelihood is the fault, whatever it is, didn't exist prior to the light coming on. So, the car worked at point of sale, so you're not covered by CRA2015 (which gives, by law, 6 months).

If you have no information on what's covered by the warranty the place to ask would be the provider of that warranty.

But given we are all a bit in the dark about what it is anyway, a good first step would be it being properly diagnosed by a garage or competent mechanic, be that the one you bought it from or a local garage or a mobile mechanic etc.

Goudy

If the belt is worn rather than broken it'll usually squeals or screeches , particularly at cold start up like first time each morning.

As the belt slips it'll often cause the charge/battery light to flicker and eventually come on as it detects low output, (but modern cars are sensitive to electrical power so it may cause an engine management light as well).
You'd often be able to drive it for a while as it will generate some electricity but eventually the battery will flatten and it'll not start, how long this takes depends on how much/little the belt slips.

If the alternator fails or the belt driving it snaps, you lose all output from the alternator.
All you have is what is in the battery and that will not last long in a modern car before the car grinds to a halt. 
Likelihood is you won't get far!

Sometimes the bearing in the alternator wear, that can cause the alternator to grumble loudly.
As it's not spinning freely it can drag on the belt, slowly it down like a slipping belt would.

As already mentioned, the drive belt is a serviceable part.
Most manufacturers recommend it's replaced every 6 years or so. This means it won't be covered by a used car warranty and would probably only be covered (for snapping) for a few months on a brand new car.

If it's the alternator that has failed it might be covered by a warranty, but not all warranties are the same and if the dealer have warrantied it himself, they tend to be only interested in pre existing faults and your alternator did work for a while when you bought it.

Of course a duff battery can give the same problems, but generally the car's electronics monitor the alternator output and it's that that is linked to the charge/battery light on the dashboard.

The car wants a few simple tests.
The condition of the drive belt wants checking. If it's old, cracked and likely slipping it wants changing and that's down to you.

The cars alternator output needs checking, this can be done with a simple voltmeter or the car can be plugged into a diagnostic tool and checked.
It should put out 14.4 volts with the engine running and respond (flicker up a bit) when a high electrical demand is turned on, like the full beam and heated rear screen.

Checking the condition of the battery is a little harder, for one you have been under charging it for a while so it might not be fully charged anyway.
But with the engine and everything electrical turned off it should read around 12.6 volts.
There is another test that tests the battery's ability to store amps, but you need different tester for that. but those simple test will usually confirm what is going on and all that's really needed is a cheap voltmeter.