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Not Just Hot, Really Hot

Just changed my alternator as my old 35amp Lucas unit given up the ghost as the voltage regulator gone to pot. This time nice new 45amp unit fitted and the car drives as if it were new (or as I remember it).
Come to double check the tension of the fan belt after its run round the block and neatly welded my hand to the case .Hot and I mean really hot.

Disconnected the battery, let it cool down and then re attached the leads to the battery the following day from cold. No keys in the ignition, the alternator starts to get warmer and warmer and ..........Hot!

Next remove the fuses to identify a circuit and still the unit gets warm with no keys and the battery connected.
Lastly removed all the blasted fuses and still it gets warm as if its drawing current off a non fused circuit.
Last resort took the alternator back, had it changed over for another one and this one too starts to heat up like a kettle. Am I missing something here ? is there a direct circuit (non fused) that causes my new unit to heat up.

Oh, battery new (No Accuspark) still on points etc as got frightened over ballast resistor stuff.
Standard Euro Connector on the Loom and this replacement alternator is the match to the Lucas 10/11 AC


Help appreciated
Thanks

The lighting circuit isn't fused, it is protected by a thermal cutout under the dash, beside the driver's door. It has 2 blue wires connected to it. Disconnect them to isolate the whole circuit from that point forward.

Also, have a look at the fuseable links, in particular the jointer's that have two spade connectors beside the battery, there could be a short there to the bodywork.

Another thought, there could be a short inside the starter. Disconnect the main terminal but be careful not to short it out when testing, cover the bare end with a lot of insulation!

Be aware though............Vauxhall used a connector with 1x positive and 1x negative terminal. More common Lucas units on other vehicles used 2x positive terminals and negative in the casing.
If the alternator is getting hot, the rectifier is faulty. Caused by the reason I explained.

StefanM wrote:Be aware though............Vauxhall used a connector with 1x positive and 1x negative terminal. More common Lucas units on other vehicles used 2x positive terminals and negative in the casing.
If the alternator is getting hot, the rectifier is faulty. Caused by the reason I explained.

Good call Stefan. I hadn't known (or possibly forgotten) that bit of info and worth noting for the future. Is it the Delco alternator that had the single + and - treminals and then a swap to a Lucas causes the problem?

I am not shure. I think vauxhall used the same setup all over the years on both delco and lucas units. The most common aftermarket lucas units is 2x positive so it better be checked before replacement.