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Voltage Regulator Epoxy Melting

Posted By: solarguy

Voltage Regulator Epoxy Melting - 10/04/12 10:22 PM

After cruising around last Sunday, I popped the hood and noticed this sticky streaking coming from behind the voltage regulator. I took it off and all the epoxy has melted out leaving a nice mess on the firewall.

Now, this reg was on my car when I got it so it's at least 12 years old, it's a dual field alt, Mopar V/R Part, was charging fine, amp meter stable, verified 14 volts at battery at high idle, engine didn't overheat, etc. In fact, I drove the car around a little even after I noticed the streaking, it still works. A new Mopar Restoration V/R came in the mail today and before I just change it out, I was just curious if this may be a symptom of something else or just the way they fail sometimes? I've never heard of this happening. Any thoughts?

Thanks
Posted By: Dave440

Re: Voltage Regulator Epoxy Melting - 10/05/12 01:13 AM

It COULD be indicative of an overheating VR....or of nothing more than old resin melting bcus.... well....it's old! It may not fail...but it's gonna keep making a mess till it runs out of goo. It's there to isolate parts from moisture and vibration.

I've seen plenty of these. VRs and Electronic ign boxes that GOO all over the firewall or inner fender and with the car running fine. I was going through a box of misc car parts in my garage not long ago that had an electronic ign box stored in it. The thing melted right inside the box! No engine heat needed!!! I bought the ecm in the late 80s to try and convert from points but never really got around to it. I took a photo...if I can find it on my computer.
Posted By: Dave440

Re: Voltage Regulator Epoxy Melting - 10/05/12 01:45 AM

found em... Photos taken 2010 and the module purchased around... 88 89 maybe. I know it was still ok a year or three prior to the photos because I go in that box every so often. Garage is warm....but not engine bay warm by a long shot!! The stuff just gets old and at that point it doesn't take much to melt it.

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Posted By: Dave440

Re: Voltage Regulator Epoxy Melting - 10/05/12 01:45 AM

2

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Posted By: Dave440

Re: Voltage Regulator Epoxy Melting - 10/05/12 01:46 AM

3

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Posted By: solarguy

Re: Voltage Regulator Epoxy Melting - 10/05/12 02:57 AM

I guess that's what happens to the epoxy when when it gets too old, I never had an electronic part outlast it's shell, they usually fail first.

Rubbing alcohol cleaned the firewall real well. New part installed and all is well. Can't complain about life span of part replaced. All the epoxy melted out, what a mess. New one on me.
Posted By: 71birdJ68

Re: Voltage Regulator Epoxy Melting - 10/05/12 04:45 AM

Check the mount bolts, thats the only place that it gets a ground. I have a hunch that the ground goes bad from corrosion and they get hot. Just a hunch. I had one that went bad from sitting, not the epoxy but the electronics went bad from sitting around.
Posted By: nomore65BelvJim

Re: Voltage Regulator Epoxy Melting - 10/05/12 06:08 AM

Doesnt hurt to have a little space for air circulation between the unit and firewall.
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