EZL (ignition module) thermal conductor paste??

[throne7]

Is the thermal conductor paste that u put under the EZL (ignition module) to mate it to the frame of the mercedes, is this the same as the household desktop computer CPU cooler paste that we use to stick the CPU fan/heatsink to the cpu to cool it down during operations? If not, where can I get some of this magic paste? I need it asap. Thx u great folks. My benz is giving me trouble again

[Chas H]

It's heatsink paste. Maybe not what's under your CPU, but your EZL isn't a CPU. I have used heatsink paste from Radio Shack under both, with excelllent results.

[Ferdman]

throne7, it's the same thing according to the Parts Department at a local MB dealer. The dealers don't sell it though so you'll have to go the Radio Shack route.

[zcc]

Yes it's almost the same and the white liquid used for the CPU is even much better than the original Bosch one.

[Strife]

When doing this make certain that the coating on the bottom of the unit itself is not compromised - I think it's supposed to be insulated from ground (the body of the car). Heat sink compound alone is not designed to do this. In the original installation of a unit the paste is held on by a thin layer of high-temp, thermally-conductive plastic; the bottom of the unit itself is coated with something (paint?). When cleaning off the compound from my spare, I went through this coating and I'm thinking about how to repair it.

[Ferdman]

Strife, as far as I could determine the thin plastic (looks like Saran Wrap) is there to keep the heat-conducting paste from getting smeared all over the fender liner. I doubt that the plastic has any heat transfer qualities itself. What you're calling paint is actually a thin coating of the white heat-conducting paste.

[blueeagle289]

I just removed the EZL Ignition Module from my 92 300CE and took off the old white paste from the bottom. I then replaced it with a coating of a silicone heat sink paste and replaced the module. I did disconnect the battery ground before doing this job. Actually, it only took a few minutes, removing four connectors and the vac line from the module and 3 nuts on the mounting bolts. Some of the old white paste was dried out a bit, but otherwise all seemed in order. I replaced it all anyway. Seems like anything you can do to avoid having to replace this inordinately expensive part -- $1200 - $2700 ??, is worth doing. (Per a comment from M.B. DOC, sometimes other modules like the coil can cause the Ignition module to fail, if the coil develops high resistance?! I don't know if I will replace the coil now; it is a $92 item from our parts group ... might be worth it?) Ben Carter

[omegabenz]

the new EZLs used to come with the paste already on them, and a protective wax paper or plastic wrap was used to keep it from making a mess within the box.

now it comes in a little syringe, but you still cant buy the compound from the dealer.

Radio Shack has "Heat Sink Compound" also called "Heat Sink Grease" part number Model: 276-1372, Catalog #: 276-1372

http://www.radioshack.com/sm-buy-the-heat-sink-grease-on-http-wwwradioshackcom--pi-2102858.html

[blueeagle289]

I removed my EZL unit and applied Heat Sink Paste I got at a parts store. It was an easy job and the paste really stays in place pretty well. Ben Carter

[mpolli]

Originally Posted by omegabenz

the new EZLs used to come with the paste already on them, and a protective wax paper or plastic wrap was used to keep it from making a mess within the box.

now it comes in a little syringe, but you still cant buy the compound from the dealer.

Radio Shack has "Heat Sink Compound" also called "Heat Sink Grease" part number Model: 276-1372, Catalog #: 276-1372

http://www.radioshack.com/sm-buy-the-heat-sink-grease-on-http-wwwradioshackcom--pi-2102858.html

It looks like they give you enough to do 20 or 30 of them. You only want to use enough to fill air gaps between the 2 pieces. The grease isn't really a great conductor of heat, it is just a lot better than air. So you want to use the least amount you can to fill the gaps between the mating surfaces.

[Larry Delor]

That's alot of money sitting right there.

[Strife]

Originally Posted by Ferdman

Strife, as far as I could determine the thin plastic (looks like Saran Wrap) is there to keep the heat-conducting paste from getting smeared all over the fender liner. I doubt that the plastic has any heat transfer qualities itself. What you're calling paint is actually a thin coating of the white heat-conducting paste.

I don't have a new one in my possession, but there is a plastic, Kapton, that is commonly used for electrical insulation AND it has good thermal conductivity that if thin enough would feel like Saran Wrap (is it colored orange?). We used to use sheets of mica (a crystalline form of silicon that is actually mined) for this in electronics, but a sheet that big would be hard to get and mica is brittle, etc.

When I mentioned paint, I really meant the paint on the bottom of the unit itself, a semi-gloss black, which is worn off a little of one of my spares.

[Strife]

If I ever have an EZL fail, I'll replace the coil on principle - it's like taking out an insurance policy at 1/20 of the replacement value. But, as you know, DOA and "infant mortality" are not exactly rare with electrical items...

[ragtopper]

Just got the Huco Ignition Control Module replacement part, which came with small tube of white thermal grease. Can someone answer this:

Is the thermal grease applied between the ICM black plastic component and cast iron/heat sink? OR, directly to fender - between fender and ICM?

Where do I apply the grease????

Ragtopper
1982 380SL

[rayhennig]

Originally Posted by ragtopper

Just got the Huco Ignition Control Module replacement part, which came with small tube of white thermal grease. Can someone answer this:

Is the thermal grease applied between the ICM black plastic component and cast iron/heat sink? OR, directly to fender - between fender and ICM?

Where do I apply the grease????

Ragtopper
1982 380SL

Apply the heat sink compound to the device you're mounting on to the car body. Apply a thin, eve, coat. More is NOT better, it is worse as it will not conduct heat so well.

In reply to someone else, the EZL in the 300-24s does not need to be insulated from the car body, it is at ground voltage. It is not like the old power transistors that were at collector voltage and needed to be insulated with mica washers.

Over in the UK we started a thread about repairing these things. We believe the most common failure mode is the output devices but we don't know whether the unit can be invaded and repaired. Does anyone here know?

Does anyone have a broken EZL that they could give to an electronics wizard for appraisal?

Best to all.

RayH