Why alternator overheat

It is not posted. I replaced the alternator but it did not make any difference. I replaced the heavy cables from the alternator to the battery. There are no wiring defects, drive belt is tight etc.

A mystery, but I do not have a spare battery to try. So I was looking for the 7 year old answer. Steve Brisbane, Australia. LOL I thought this was a new problem. Some time back my previous alternator failed.

When I took it apart, I saw that one of the diodes was dud. It looked like the entire rectifier assembly had been overheating, but I put that down to the shorted diode. My car is a V12 Jaguar. I replaced the faulty rectifier, and changed the voltage regulator.

But the symptom that I described had not gone away. I dismantled the alternator again, and concluded that there may be shorted turns in one of the stator windings. I could not source a replacement stator coil, NLA , so I had to fit a replacement alternator later design, as original pattern alternator was obsolete.

I could not source a replacement stator coil, NLA , so I had to fit a replacement alternator later design, as original pattern alternator was obsolete what you need to do is measure the alternator output current. I do not like these vehicles electrical systems very poorly designed Hi jc AT, Thanks again for your post. A short in the door window motor circuit would trip the thermal cut-out, and only when the window switch is operated.

Same for door lock solenoids. Q: Alternator is overheating What would cause this problem? My car has miles. My car has an automatic transmission. Jessica Howe Automotive Mechanic. The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details. Home Loss of power Inspection. Experienced Mechanic? Apply Now. What others are asking How do I return the personalization settings to factory settings?

At any point, you can return all of the personalization in the vehicle to factory settings. This is very easy to accomplish: 1. Turn on the infotainment system. Read more. Replaced multiple parts and car still won't start Wow that is a lot of replaced parts. Assuming all the new parts are good I highly suspect a problem with either your cam or crank sensors.

If either of these sensors fail your engine will not know when to Radio interior lights IOD Since the problems go away when the radio harness is unplugged, this sounds like a bad ground, or loose power supply connection related to that installation. Strange noises. Car stalls or has difficulty starting. Battery dies. And power-up wires to operate the dash area and electrical system will also connect at the battery.

Smell of Burning Rubber The scent of burning rubber or scorched wires sometimes indicate an alternator failure. Friction between a misaligned belt and the pulley will emit a smell of burning rubber. The burning wire smell can be caused by an overheated alternator.

The battery measures The alternator gets hot fast - uncomfortable to touch in just a minute or two - while the rest of the engine is still cool. After 5 minutes, it is untouchable. In the 's the typical underhood inlet cooling air temperature to the alternator was 90 o C. By the 's this had jumped up to o C. Today, applications approach the o C range. But the demands on the thermal design don't stop there. Check the battery first.

Turn off the car. Open the hood. Connect the voltmeter to the battery. Read the voltmeter. If the battery doesn't have enough voltage, either get the battery charged and re-test or try a different method for checking the alternator. When an alternator fails, the bearings inside usually have failed to a point that causes them to whine severely and, depending on how badly they have failed, they may also smoke due to the excessive friction they create.

Another cause of alternator fires involves repairs. When an alternator is replaced, the connector should be examined. If the connector is not in good connection, it should be replaced as well. A damaged connector can cause wire melting and subsequently cause a fire.