Alfa Romeo Bulletin Board & Forums - View Single Post - Changing the Voltage Regulator in Alternator
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post #4 of (permalink) Old 07-04-2019, 03:28 AM
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kuseetha's Avatar
Join Date: Dec 2012
Location: Sri Lanka
Posts: 102
Originally Posted by BlackAlfa View Post
24V alternator and voltage regulator are slightly different from the pictures that Steve posted. The 24V alternator has a plastic cover at the back of the alternator and it has to be removed to get to the voltage regulator. But in order to take the plastic cover off, the front exhaust manifold heat shield need to be removed first. In the first picture, you can see the heat shield was drop down and the alternator back plastic cover was move to the side. The A/C hoses are somewhat in the way. The second pic shows the voltage regulator as mounted on the back of the alternator. The lower two pics show the voltage regulator.

Why I pulled the voltage regulator? The car was showing inadequate electrical power supply symptoms (even with a new battery) - voltage dropped too much whenever I switched on some additional loads. I pulled the voltage regulator today and cleaned all the electrical contacts that I came across. I put the old voltage regulator back (don't have a new one on hand) and some preliminary measurements show that the charging system is working much better now. It was charging at ~14.6V with engine idling and it still stayed at ~14V with most electrical accessories turned on (before cleaning, it dropped below 12V)!

Thank you so much. I had this problem of overheating when the A/C was ON. I found out it happens because alternator output is low when electrical load is high (goes to low 12s in Voltage), then the radiator fan spins slower than required. So the temp rises.

I anticipated a total removal of the alternator and replace its internal regulator. But thanks to you, I managed to scrub clean the 3 contacts and push them a little bit forward with pliers so they contact well. Now with headlights ON, AC ON and blower fan at full speed and radiator fan at high speed, it still stays above 12.9V.

I have to replace this part but for now, this is manageable. Thank you once again.
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