Question on Thermal Paste on mounting plate for an ICM

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89 Reatta. I think my Ignition Control Module failed me the other day when it reached about 101 degrees in Texas. After the ICM  cooled down, everything was fine again.  The Magnovox ICM is not that old, I don't use this car that much. I've read where you are suppose to use a thermal paste on the mounting plate when installing the ICM. I don't recall doing this when I install the ICM on this car, I might have caused it to have failed prematurely .  I've read where some people use dielectric grease, but it does not have the same properties of thermal paste.  Any opinions on this thermal paste?



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"Thermal Paste" and/or dielectric grease isn't needed, and too much of either could actually hinder it. The large aluminum block bracket that it mounts to is a sufficient heat sink, and also acts as it's ground connection (the negative battery cable is bolted to the bracket)


When I first replaced my '89 Magnavox with a new unit- both the underside of the ICM and mounting surface of the bracket were badly corroded (non-conductive aluminum oxide) that I removed, using both PB Blaster and dielectric grease, with a putty knife. I then rubbed in some dielectric grease- to protect the raw aluminum, and used paper towels to wipe up any access. You jus want to "whet" the surface, you know what I mean? Like waxing a car. It's 3 mounting bolts act as decent electrical connection.


I later switched to an "AC Delco" type ignition, with great results.

















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RDG, Thank you for that info. I'll do that when I replace this bad one. I'm thinking about doing the switch to that AC Delco ICM , but I might first try that new Wells Duralast from Autozone and see how that holds up. If it doesn't then I'll do the switch.  


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I used sand paper to remove the crud and then sprayed it with carb cleaner and let the cleaner flash off. 

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