Private Car Sale Transaction, Car Unroadworthy.

honestgaz

Alderbank said:

GDB2222 said:

honestgaz said:

Aylesbury_Duck said:

lincroft1710 said:

Alternators can fail at any time, they are consumables. Alternator was working when car driven away, could OP prove seller knew it was about to fail  I doubt it.

Worth looking to see if the battery warning light indicator has been disconnected or taped to hide it?

Battery light indicator came on during the drive home

Does the light come on when the battery is low, or when it is not being charged? 

Fair question.

The light comes on whenever the voltage on the lead from alternator to battery falls below 14v.

With ignition turned on but engine not running the light, like all other warning lights, should be on. That is a very basic first check when test driving a car. It confirms that the light has not been removed or disconnected.

When the engine starts and as long as it is running the alternator outputs a minimum of 14v. This extinguishes the light. If the light comes on while the engine is running it means

1. the alternator has failed
2. the alternator belt has broken
3. there is a bad connection between alternator and battery
4. something is drawing such an abnormally high current that the alternator cannot maintain 14v.

It tells you nothing about the state of the battery (unless it is in such a bad condition that its internal resistance is exceptionally low). Even a brand new, fully charged battery only delivers a maximum of 13v.

Thank you so much, will put the battery back in the car. Hook it up and check and report back.
I am crossing my fingers that it isnt the alternator

honestgaz

Alderbank said:

GDB2222 said:

honestgaz said:

Aylesbury_Duck said:

lincroft1710 said:

Alternators can fail at any time, they are consumables. Alternator was working when car driven away, could OP prove seller knew it was about to fail  I doubt it.

Worth looking to see if the battery warning light indicator has been disconnected or taped to hide it?

Battery light indicator came on during the drive home

Does the light come on when the battery is low, or when it is not being charged? 

Fair question.

The light comes on whenever the voltage on the lead from alternator to battery falls below 14v.

With ignition turned on but engine not running the light, like all other warning lights, should be on. That is a very basic first check when test driving a car. It confirms that the light has not been removed or disconnected.

When the engine starts and as long as it is running the alternator outputs a minimum of 14v. This extinguishes the light. If the light comes on while the engine is running it means

1. the alternator has failed
2. the alternator belt has broken
3. there is a bad connection between alternator and battery
4. something is drawing such an abnormally high current that the alternator cannot maintain 14v.

It tells you nothing about the state of the battery (unless it is in such a bad condition that its internal resistance is exceptionally low). Even a brand new, fully charged battery only delivers a maximum of 13v.

So, did all you said.
When the car is turned on, all lights come on, including battery light.
When the car is started, all light go off, including the battery light.

honestgaz

However, when testing with a Multimeter. The battery returns 13v, with the engine turned on it does not increase at all to 14V+. So none the wiser

Ayr_Rage

When the engine is running there shouldn't be any orange or red warning lights showing.

Alderbank

Is that with the engine just ticking over? Run the engine at a steady 2,000rpm and check again. Also check that the alternator belt is tight and is not slipping.

Here is a good guide to testing your alternator with a multimeter:
https://tameson.co.uk/pages/alternator-multimeter#:~:text=In%20most%20cases%2C%20car%20batteries,higher%20voltage%2C%20typically%2014.5%20volts.

GDB2222

I must say that I have sympathy with the OP. It's a really mean trick to wave someone off in a car, knowing it's bound to break down en route. I'm not impressed by FB marketplace.

born_again

honestgaz said:

However, when testing with a Multimeter. The battery returns 13v, with the engine turned on it does not increase at all to 14V+. So none the wiser

I would suggest you take it to a local garage & get them to check it out.

lincroft1710

So we have gone from a forthright

"the alternator is faulty"

to

"I am crossing my fingers that it isnt the alternator"


OP definitely made the right decision in coming to MSE before embarking on any court action

GDB2222

An alternator is a couple of hundred pounds - not much in car terms. 

Tucosalamanca

So what did the recovery services say? Was the battery condition checked at the roadside?

Even if the alternator was not working, the car would continue to function until the battery died.
At the time, I would have expected the battery to read around 11v or lower.

Since you've removed the battery from the vehicle, can we assume that it's since been charged?
What voltage is it holding, after charging and resting for a few hours, I would expect the battery to be above 12.3v (or higher if in very good order).

If the battery appears to be ok and is holding a good charge, you could always start it up, run with lights, fans etc turned on and see how long it takes for the red battery light on dash to appear. This would give a good indication if the alternator is faulty or not.

If you're uncomfortable driving it to the nearest garage (which is what I would do) then simply book a mobile mechanic.

A battery or alternator defect is not hard to diagnose or repair. Good luck with it.