moisture proofing ignition?

WD-40 is fine for removing moisture from ignition wires, distributor caps, etc. It does not conduct electricity significantly. Silicone sprays are pretty good at repelling moisture, but not so good at dispersing or removing it.

Unless you are in a really tough environment, treatment once or twice year should be enough.

I'm thinking a silicone dielectric grease (like syl-glide) might be better inside the boots than white grease. Also a silicone spray on the wires might help repel water, similar to treating your door seals. Beyond that there's not a whole lot you can do. WD-40 inside the dist. cap is fine.

nate

Probably, if you'll tell us the make, model, engine, and year.

WD-40 will probably evaporate in the high underhood temperatures, and I don't like having any lubricants on the exposed areas of ignition system parts because they attract dust and oil, which leads to formation of carbon tracks that short the spark energy to ground and can even crack distributor caps and rotors. Keep everything clean, and fill connections with thick, non-runny dielectric grease (Loctite, Radio Shack, transistor heatsink paste). Syl-Glide will run because it isn't filled with zinc oxide powder as dielectric grease is.

Plug in the block heater a couple of hours before departure ... does a decent job of drying things out. And since the engine warms up shortly after starting, it stays dry. Else replace all your high tension stuff ... cap, leads, boots ... and not with the cheap stuff ... or maybe that's when the problems began?

NO.

A dielectric substance is one that DOES NOT conduct electricity. The Zinc-filled greases (Noalox, Ox-Gard) are *CONDUCTIVE* pastes intended primarily to prevent junction problems in aluminum household wiring.

DS

If the plug wires, coil wire and the distributor cap and rotor are in decent shape you shouldn't need to moisture proof anything, they should seal good enough normally. I think just as the previous poster recommended, new wires, distributor cap, and rotor of a good quality will fix your problem.

YES. Pure grease runs and needs a powder filler to prevent this.

Who said or implied otherwise?

I said zinc OXIDE, a dielectric, not pure zinc powder, a conductor. Don't omit words and change meanings.

Show us this alleged Zinc Oxide dielectric grease and maybe I'll believe you.

"Us"? That's a bit imperial and presumptuous. What do you think usually makes dielectric grease thick and opaque white? Zinc oxide, possibly the most common additive put into silicone grease.

Try these:

Radio Shack #276-1372

Maybe he's using this as a dielectric grease:

All the automotive dielectric greases I've seen for sale in eight states and two provinces have been thick due to formulation, not due to additives. And, they've all been colorless transluscent, not opaque white.

I don't go shopping at s*it shack for anything other than cheap Chinese electronic toys for nieces and nephews. Certainly not for car-repair supplies.

Another distinctly non-automotive source of non-automotive products.

Yet another non-automotive source of non-automotive products.

I'm sure this Zinc Oxide silicone grease of yours exists and can be used satisfactorily in certain automotive applications. But it is not what will get pointed out or placed on the counter when someone goes to an automotive parts and supplies source and requests dielectric grease.

DS

Well, dielectric grease is generally clear, not white.

Thermal heat-sink greases are not always interchangeable with DIELECTRIC greases. Heat sink greases are made primarily to conduct HEAT, and whether or not they conduct or insulate electricity is secondary. The white ones are not strongly conductive, but the breakdown numbers on those sheets are definitely lower than true dielectric greases. Dielectric greases are specifically made to have high electrical resistivity and ability to resist dielectric breakdown (arc-through).

Like this:

Thank you. The voice of reason. If your components need moisture proofing, they need replacement. The WD40 thing is fine to get you going on a stop gap basis. It really does work but, after it dissipates, you will have the same problem repeat until you repair it correctly.

You asked me to show that dielectric grease containing zinc oxide existed, and I did. You didn't say it had to be from the auto industry, and there's no practical difference with the silicone-based ones marketed for electronics use. The last GM car I had, a 1980s model, came with opaque white silicone grease all over its tail light connections.

They may not know it, but that is what they'll usually provide.

Why did you even mention zinc-laced grease for dielectric purposes? No competent person would confuse pure zinc with zinc oxide.

Probably true in most cases, however, some vehicles (esp. old British cars) still needed some extra help even with all components new.

I'd also add that even "brand name" components may still cause problems; I put a set of Bosch plug wires on an old VW once and they failed within a year. Apparently OEM Bosch and aftermarket Bosch are two different animals. Not sure what the replacements were (I took it to a shop because I was sure I had serious problems) but it was still running fine several years later when I sold it.

nate

Joe Br> If the plug wires, coil wire and the distributor cap and rotor are in

Check the headers, boss. rec.AUTOS.tech. We're not here to discuss repair materials for our Zenith television sets.

A practical difference there may not be, but a composition difference there certainly is.

Thanks for all the info. I think the idea that spraying will attract dirt deposits is a good one. Best to just keep clean. If this happens again I think I will wipe everything clean and dry with the engine idling, starting at the coil, and see if that will isolate a particular problem area.