I'm curious on your guys' thoughts on the use of dialectic grease.
I have to assume it's a good thing to use, but I see all kinds of advice out there and I'm not sure what's legitimate or not. I do not have an electrical engineering degree. My CompSci missed all of the cool classes that might have taught me about this. I see some people say that you should just load up a harness plug / socket, saying that it will "improve conductivity." But logic would tell me, if it improves conductivity, then would it not increase interference between the plugs if it's literally now bridging the gap between the individual pins?
I see this everywhere, and it makes no sense to me. I would instead hypothesize that all it's doing, is filling a potential void with gel, which inhibits water intrusion, and prevents corrosion from dissimilar metals, or "galvanic" corrosion (I think it's called).
My daughter is going to be pulling the wiring harness, and snaking it around the engine with all the proper sensors and connectors, and I'd like to teach her what's legitimate, and not continue to perpetuate myths.
Dielectric grease in an electrical insulator, designed to prevent electrical signal migration and is an excellent water repellant.
Put a dab of it on the weatherpak connector seals if you care to. I do recommend it for grounds.
The stuff GM put in the C500 connector is amazing, and should not be cleaned out of the connector and replaced, it's still gooey after all of these years and can be reused with no issues.
Dielectric grease in an electrical insulator, designed to prevent electrical signal migration and is an excellent water repellant.
Put a dab of it on the weatherpak connector seals if you care to. I do recommend it for grounds.
The stuff GM put in the C500 connector is amazing, and should not be cleaned out of the connector and replaced, it's still gooey after all of these years and can be reused with no issues.
Thanks Joe, any idea what GM originally used in those connectors?
1. Remember "Water" is often very polluted w/ road salt & way worse things that corrode the connectors... 2. Up until the 70's Many parts in the engine bay & most still got installed Dry or bare minimum of protection & parts rot like old generators & alternators w/ external regulators. 3. Do Not believe most "data" that often came from the "PC world" (including the magazine) that uses "Arctic Silver" & worse products like "Liquid Metal" containing Gallium etc that Attack Aluminum.
GM et al use a thick grease since 50's or 60's typically called "Bulb Grease" to keep out "water" because even @ high temp @ the base of a light bulb the grease won't run separate etc. Bulb Grease is very likely Cosmoline still use by U.S. Mil for ~ 100 years now. You does need to clean it off normally. If have Skinned over w/ dirt etc then scrape the skin away before you push the dirt in whatever. This is often "better" then Weather Pack & more "water proof" plug systems but takes time & makes a mess dealing with it @ car factory so didn't use that everywhere.
Dielectric Grease is just Silicone Oil w/ Silicone Solids & few other additives. This can & will separate even in the package even @ "room temp" but slower. Note: White Heat Sink Grease/Compound is Silicone Oil w/ Zinc Oxide to replace Silicone Solids to move heat better the DG but often does same thing w/ the oil but unlike most in the PC world say does nothing when dry, real engineers know not true & why many things still use this grease. Do Not use any thick grease on big parts like DIS ICM/PIM as surface can deform before spreading the paste.
DG itself is near Inert & electrically insulating but fills small gaps when metal touches or rubs on each other but often doesn't last long dealing w/ hot wet places like any engine bay. DG does Not help a connection to be "Better" when installed but keeps moisture out that Starts most types of corrosion. You need electric insulation so doesn't short 1 pin to the next unlike some other greases that may not cause a "dead short," can carry enough electric to totally F'd things like the ECM/PCM trying to "read" the sensors.
That's said, I keep pushing Permatex Green label Brake Grease because is Plastic/Rubber Safe & won't run or wash off easy when used things like ground bolted to the block. This does Not have silicone oil & never dry out even in/on the engine except on exhaust parts. I use this on DIS ICM because thin enough to flow out to move heat & keep out "water."
Weather Pack et al on Paper may seal for Decades but have many problems like have a wire pulled "sideways" @ the back often "leaks" to let "water" in the connector then rot often quickly. If you have problems like that, a very thin coat of silicone or permatex brake grease does work even here but may need special tools to get some apart. Too much grease can "blow out" of the connectors.
Example: Many put silicone on spark plug boots but they stuff the boot w/ too much, grease expand & boot pull the wire off the plug @ minimum. Worse can push the boot all the way off the plug cause very big problem burning dist cap & rotor, fry ignition coil(s), etc.
Weather Pack Et Al are Not "Water Proof" but "Weather Resistant" @ Best & never made to have a car driven in deep water. Bulb Grease etc won't help you for that too. "Deep water" for most cars are only 4" to 6" deep but Many SUV & "Crossovers" are in same category but fools thing the water isn't getting inside then safe to drive... That's often starts problems because "water" is force inside many ABS and other sensors.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Thanks guys, I appreciate it! Biggest thing I wanted to get out of this was that dialectic grease is NOT conductive... which was a huge concern for me (because I heard a lot of people say that), and in fact, all it does (well, it's purpose) is to prevent corrosion and water intrusion. Which is super important to me, and I will heed that advice.
Before I go "ape" with the dialectic grease...
Ogre... when you said, "That's said, I keep pushing Permatex Green label Brake Grease because is Plastic/Rubber Safe & won't run or wash off easy when used things like ground bolted to the block." Where specifically did you mean you use this? Externally on the block grounds, or are you saying you pack the weather-pack connectors with this?
Is this what you use as a replacement instead of the stuff that Joe mentioned that came from the factory in those connectors?
Joe, on removing the C500 block. My daughter is going through the entire car, completely. It's got over 200k miles an we're going through everything... in part because she wants to learn as much as we want to completely re-do the car so she has a "new" car. So, we'll be going through that too. The car is faaaar too old and beyond the point at which we would "fix things as they break." The car needed a complete tear-down and restoration... which was kind of the goal. I haven't done the electrical yet, but I intend to make sure we use the grease liberally.
The wiping action of the connectors will make the electrical path regardless of the dielectric grease. The grease is there to keep everything else out. If the grease makes the connection worse, it was bad in the first place.
That being said, any modern sealed connector wouldn't need it. The proof is in the pudding, go to any junkyard and take apart a weatherpak or metripak connector. They're all fine.
I'd be hard pressed to believe the stuff in a C500 connector is cosmoline. That dries to a hard wax and is miserable to remove. Old school bulb grease does kind of remind me of the stuff. Like molasses.
Either way, the majority of these cars aren't getting beat on like they were in the 80's/90's, going through multiple winters and never being washed, so you're probably fine with less extreme measures.
(or replace all of that 80's stuff with sealed connectors. I did that on my S-10)
I can tell you with great confidence ( from having pulled apart and repinned dozens of C500 connectors ) that there is absolutely no need to do anything in that area of the car except inspect the wiring for cracks and clean the exterior of the connectors.
!!NEVER!! pack a weatherpak connector with anything! If you want to do something, put a tiny bit of dielectric compound on the rubber seal and on the wires where they enter the connector.
I can tell you with great confidence ( from having pulled apart and repinned dozens of C500 connectors ) that there is absolutely no need to do anything in that area of the car except inspect the wiring for cracks and clean the exterior of the connectors.
!!NEVER!! pack a weatherpak connector with anything! If you want to do something, put a tiny bit of dielectric compound on the rubber seal and on the wires where they enter the connector.
Ok, I guess I'm confused here... the C500 connector is the one that goes through the bulkhead just before it connects into the ECM, right? You're telling me I should leave it alone? I'm completely restoring the car, which means I'm going to be sanding down and repainting the firewall as I've been doing with the rest of the chassis / frame. I also want to completely inspect and re-do the engine harness because it's 40 years old and has been tinkered with. Can I remove the entire harness from the car without having to disconnect the C500 connector? Just want to make sure I'm on the same page.
I can tell you with great confidence ( from having pulled apart and repinned dozens of C500 connectors ) that there is absolutely no need to do anything in that area of the car except inspect the wiring for cracks and clean the exterior of the connectors.
!!NEVER!! pack a weatherpak connector with anything! If you want to do something, put a tiny bit of dielectric compound on the rubber seal and on the wires where they enter the connector.
Agree 100%, it's the wiring on these cars that are breaking down, not the connectors.
Originally posted by 82-T/A [At Work]: Ok, I guess I'm confused here... the C500 connector is the one that goes through the bulkhead just before it connects into the ECM, right? You're telling me I should leave it alone? I'm completely restoring the car, which means I'm going to be sanding down and repainting the firewall as I've been doing with the rest of the chassis / frame. I also want to completely inspect and re-do the engine harness because it's 40 years old and has been tinkered with. Can I remove the entire harness from the car without having to disconnect the C500 connector? Just want to make sure I'm on the same page.
Thanks!
You need a shop manual!
The C500 connector lives in front of the passenger side strut tower. The engine harness and tail light harness plug into it
The C203 connector lives below the ECU, the top part is white, and the bottom two pieces are black.
Rather than replace the entire harness, I would clean up the looming and repair what you have. If you insist on replacement, be aware that it will have as many miles on it (or more) and will suffer the same or worse problems.
Every Fiero harness I have disassembled, no matter the miles, has been in very good shape inside the looming. The problems arise in the exposed wiring areas and with broken connectors.
That should do for many users for a lot of bulbs or relay sockets but C500 maybe only once if completely clean.
No-one should remove the bulb grease completely or put new crimps in a connection by hand tools. GM et al uses Air or Hydro crimpers that crushes the crimps way tighter then a hand tools available to the public or to many "pro" shops. More The crimper are often Calibrated to squeeze the crimp & wire just under Failure Point to nearly "cold weld" the parts leaving no Voids to let "air" & "water" inside.
Is Very Likely Part or Why GM Stopped wiring the Alternator thru C500 (or C100 for other model lines) because bigger wire have bigger "pins" & need another Air/Hydro Crimper for installing this costing more to make @ factory.
This is Why many say crimp then solder "pins" & other ends that have high current or need very accurate signal but most installers have no clue how to solder right & make a mess.
Originally posted by olejoedad: You need a shop manual!
The C500 connector lives in front of the passenger side strut tower. The engine harness and tail light harness plug into it
The C203 connector lives below the ECU, the top part is white, and the bottom two pieces are black.
Rather than replace the entire harness, I would clean up the looming and repair what you have. If you insist on replacement, be aware that it will have as many miles on it (or more) and will suffer the same or worse problems.
Every Fiero harness I have disassembled, no matter the miles, has been in very good shape inside the looming. The problems arise in the exposed wiring areas and with broken connectors.
Thanks Joe, I already have a shop manual. I've got an 84, an 85, an 86, and an 87... all reprints except the 84. I use the 85 one for pretty much everything on the car. We just haven't gotten to that part yet and didn't feel like looking it up since we were already talking about it, and it's in the garage.
The wiring is unfortunately a mess though, and that block has already been removed several times before we got the car. It was all working though, to be fair. There's rust in the top frame rail, so it all has to come out anyway as we repair that and weld in a new battery tray as well. We're probably... well, definitely giving this car a lot more attention than it's probably worth. The guy who owned it did a great job maintaining it... but again, it has over 200k miles on it, and it's just tired. Most people at this point would have just junked it, but like I said, this was an opportunity for me to teach my daughter a valuable skill that can help her be more mechanically inclined.
I won't be replacing the harness, as this is a mostly stock rebuild, but as part of the restoration, we're going through the entire car. I am replacing several of the connectors that have gone bad or where the clips have broken. I am also not a huge fan of how the factory wiring was laid out across the engine. I know some people will fuss here, but when these cars were built, the harness came with the engine from the factory that assembled the motors, and done in a way that was the most cost-effective, and the easiest to install for the line technician.
I'm more interested in functionality, and improving where the wiring goes. I'm steadfast in the idea that no wiring should protrude down through the front of the motor... I mean, unless it's got a crank reluctor or timing wheel or something. There's no reason (for example), why the A/C compressor harness needs to go down through the center of the motor. I can significantly clean up the motor by getting rid of the black plastic conduit.
Even the bolts on the coolant block-off plate (where the water pump would go in a longitudinal installation). We plan to replace the studs with actual similarly rated bolts once we know that we don't need the actual studs in there for anything. I want the motor to be as clean as possible, and uncluttered. I'd like for everything that's connecting to the motor, to come in through the back of the engine (where the engine and transmission meet), protruding off the firewall and attached right above the bell-housing. Basically... the factory location where MOST of the wiring goes, but I want all of the wiring to go through there. For the A/C compressor wires, I plan to run them under the exhaust manifold shielding, and affixed to the block through little wiring brackets like exist in the front.
I bought several of these, for both mine and my daughter's Fiero...
Anyway, we plan to go through the whole harness, lay it out on thee engine how we want it, resolder all new factory plug-ends, replace some wires only if necessary (and use the factory colors), and then bundle it up with wire loom and shielding tape in the way the factory would have. I want it to look good as well as functional. We're also upgrading to all serpentine, and the newer V5 A/C compressor as well.
Like I said, this Fiero... it was at the point that most people would have junked it. But it ran (meaning the engine was rebuildable), and it was "complete." Which is saying a lot... because Fieros aren't really in the junkyard anymore.
quote
Originally posted by theogre: Is Very Likely Part or Why GM Stopped wiring the Alternator thru C500 (or C100 for other model lines) because bigger wire have bigger "pins" & need another Air/Hydro Crimper for installing this costing more to make @ factory.
This is Why many say crimp then solder "pins" & other ends that have high current or need very accurate signal but most installers have no clue how to solder right & make a mess.
This is what we're going to do also. I've already repaired the coil to ignition coil harness, and soldered in new pins for the connector replacement (clip was broken, and it was held on by a zip tie).
[This message has been edited by 82-T/A [At Work] (edited 06-03-2024).]
Originally posted by 82-T/A [At Work]: Before I go "ape" with the dialectic grease...
Ogre... when you said, "That's said, I keep pushing Permatex Green label Brake Grease because is Plastic/Rubber Safe & won't run or wash off easy when used things like ground bolted to the block." Where specifically did you mean you use this? Externally on the block grounds, or are you saying you pack the weather-pack connectors with this?
Is this what you use as a replacement instead of the stuff that Joe mentioned that came from the factory in those connectors?
Can use PGBG on many connections... Examples: Grounds bolted/screwed to anything. + wires to the dist block under C500. Dash back where bulbs & gauges connect in https://www.fiero.nl/forum/Forum2/HTML/146784.html Fuel, Engine Temp or Oil Pressure gauges have problems?
Even if the brake grease hold dirt some, stop that getting @ the metal. Deoxit etc may work "better" @ some points not others plus use PGBG as indented & cost way less. Example: Deoxit may work for dash backs but not grounds bolted to engine or frame because too wet & big Voids to hold the "water" that PGBG prevents. I use so little grease often can barely tell is any there so can't hold a lot of dirt on most things. Grounds bolted to X use more to fill Voids more so on engine "grounds" where many have "lock washers" in the terminals.
You Don't what them on the Outside of Weather Pack or anything else. Most times you don't need it on the Weather Pack "pins" too. Might help only on silicone rubber seal like big one on MAP plug that often get damage from unplugging over the years. If you have a WP plug in "weird" places allowing "water" to sit then can use the Release Tool to take apart then coat the "pins" for added "water proofing."
But problem is Old WP Plugs can break when you unclip the back cover & many bodies are very hard to get even from Dealers 30+ years ago now 0% available for many plugs. Other plugs like newer Metripack Pull to Seat are very hard to release even w/ right tool & now how to work w/ them. This "new format" is what the new ECT of ECM is & why only sold to most buyers as Pigtail Kits.
So many times I only recommends most can only spray Plastic Safe connect cleaner w/ lube from CRC etc in the pins then push the plugs together a couple times. the cleaner & small amount of lube left should even coat the "back" you can't see w/o taking them apart. Or try Deoxit etc & follow directions on them.
I have two 2oz tubes of PGBG that only got 2nd because couldn't find 1st > 10 years ago. Older is likely 30+ years. I still have both them because you need so little even on most Brake Jobs. And I use this way more then said here. Just don't use it on Food or Plumbing equipment. Would lube them but likely Toxic. (Can get Food Safe Si oil/grease from Restaurant stores, as plumber si grease, etc.)
[This message has been edited by theogre (edited 06-03-2024).]
