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Discussion Starter #1
My friend's newly acquired 2004 V6 3.2 alternator gets hot a few seconds after starting the engine.
We are investigating issues like bad battery or alternator wiring but if you have any other ideas please shoot.
 

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The alternator is water cooled.

Are you checking it when the coolant is still warm... That could get you a hot alternator pretty quick.

I never checked the temp of the alternator, but I don't see how it could get instantly hot if you started it when the engine coolant was cool.

That's all I got for now. Good luck to you.
 

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Discussion Starter #3
We did some tests and temps seem to be around 60c when engine starts from cold. Battery is at 12v which is not good. If we disconnect the alternator from the system it cools down. Once connected to the system it heats up because of the load and the dying battery. We will see how it behaves with a new battery.


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If you have a clamp on amp meter, you could clamp it over the wire leaving the alternator and / or the wire right at the battery. It would give you a clue of how many amps are running.

Going by memory, the USA T1 should have an 190 amp water cooled alternator. If you are pulling a lot of amperage, then I can see it warming up pretty quickly.

The meter could confirm your battery possibility. If there is a large amp dump into the battery after start, that high load would be why the alternator is running warm so quickly. The more amps you pull equals more heat produced.

I agree with your reasoning that replacing a bad battery could alter the situation.

If you have not used an amp meter before, it works pretty much like the video.

 

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Discussion Starter #5
Thanks for the info. It's not my Treg. I helped a friend buy one based on my experince with mine. We talked about the clamp meter yesterday and he was planning on getting one and using it next in the troubleshooting process. We'll see if it't gonna be a new battery or a new alternator by the end of the week.


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Couldn't it possibly be that some bearing has worn out in it and it's close to seizing, and that's why it's overheating (ie. because of friction heat)? I don't think it should overheat just because it's under load for an extended period of time.
 

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Discussion Starter #7
We will do some more tests and maybe get it out and check. My friend is ready to buy a new one but I'd like to make sure the issue is not somewhere else.


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Discussion Starter #8
We will do some more tests and maybe get it out and check. My friend is ready to buy a new one but I'd like to make sure the issue is not somewhere else.


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I would try the different battery first, before changing the alternotor. A battery is a lot easier to change and they are a wear item.
 

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I would try the different battery first, before changing the alternotor. A battery is a lot easier to change and they are a wear item.
If you were already going by what's easier, then you should test the battery first (with a battery tester), and not replace it unless it fails the test. Throwing random parts at a problem until it goes away, even if done seemingly strategically, is not a actually good strategy anyway. Unless probably replacement of said parts is pennies and it would cost more money and time to find the actual culprit than to just replace everything that's possibly the cause.
 

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Couldn't it possibly be that some bearing has worn out in it and it's close to seizing, and that's why it's overheating (ie. because of friction heat)? I don't think it should overheat just because it's under load for an extended period of time.
A bearing issue would also be present when they "disconnect" it from the load as per above.... unless he meant that they actually removed the belt drive off it, not just the electrical load.

If it's the electrical load we are talking about, I'd suspect some short in the system that is causing some massive amp draw.... probably in a main supply wire that's not fused and is shorted out on the frame\engine, etc. Check your power feed to your fuse blocks or anything else that some butcher might've "hard wired" directly to the battery\alternator without using a relay\fuse, etc.

Any custom additions? Lightbars, fogs, winches, etc?
 

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Discussion Starter #12
No visible mods. The aternator runs cool when still connected mechanically and running with the belt but warms up fast when connected to the load. That's why we suspect the load. But maybe 60c is not that high. Let's see how we figure it out this weekend. Anyone with a v6 petrol to try. Engine cold, fire it up, give it a minute the check alternator the temp or touch it. Don't burn yourself :)


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While I don't know what temp the alternator should be running right after engine start, 60c is not too hot for a water cooled alternator. How hot is it going to be running when the engine coolant is at full temp? The coolant thermostat is 90-95c

So, the alternator can handle 60c temp. The only question is should it be that hot, that soon after start?
 
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