Don Del Posted August 10, 2023 Share Posted August 10, 2023 I have had a Megajolt system fitted to my 3.5 V8 110 Station Wagon for over ten years without any major issues other than a failed VR sensor which Nigel helped me sort out. Periodically I get the nagging feeling that I should do something about waterproofing the VR sensor installation given where it is mounted. I have scoured various threads and haven´t really come across anything giving a comprehensive answer. My take so far is that a dielectric grease would be OK inside the boot and on the wires entering the plug. When it comes to the female side of the plug and the pins on the sensor things seem to be a bit more up in the air. Dielectric grease here seems to be a bit of a no-no though I have across numerous posts elsewhere which state that the metal to metal contact that occurs between the pin and connector effectively forces the grease out of the way and electrical connectivity is not affected. Having said that I have come across an equivalent number of posts saying not to even consider doing it. I have also come across posts on this site suggesting Vaseline or WD40. Though I would have thought WD40 would be something to try after the event of water ingress given its propensity to dry out over time. At the moment I am considering putting dielectric grease at the back of the plug under the boot and in the "valley" between the connector housing and the shroud around it. I would really appreciate any suggestions or comments (polite ones only of course). regards, Del Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 10, 2023 Share Posted August 10, 2023 I shove vaseline in most of the connections on the car and never have a problem. It needs refreshing every now and then as it has a tendency to dribble out in the hotter places, be interested if there is a high temp version of dielectric grease? The sensor itself is waterproof, so you are only trying to protect the pins from corrosion, you can get waterproof JPT plugs, but they are expensive and can be quite good at keeping water in... Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2023 Share Posted August 11, 2023 In most applications, my feeling is that it's better to allow a path for water to drain out than try to fully waterproof it - as often it just keeps water (condensation possibly) inside. In other cases, my go-to's are: RayTech Magic-Gel https://www.raytech.it/en/product/low-voltage/fillers/gel/magic-gel This is amazing stuff! Fill a void in an enclosure or connector shell & it renders it completely waterproof. However, it's easy to remove (just tears off cleanly) and if you poke a multimeter probe through it, for example, when you withdraw the probe it self-heals the hole! You can get small bottles from Toolstation. It has good dielectric properties - but sadly is a poor thermal conductor - In your case, this doesn't matter though. When there isn't a void or shell to fill, I use Conformal coating which is normally used to coat PCBs. It has a long life, it's waterproof and provides strain & vibration relief.https://www.amazon.co.uk/MG-Chemicals-419D-55ML-Premium-Conformal/dp/B07B8RY7M6/ref=sr_1_2 It's available as Silicone, Polyurethane and Acrylic. I've found Acrylic sticks the best to most things - but can be brittle. In a connector shell without really good strain relief, I'd probably use the Silicone type. I've used it like paint on insulating tape! Lastly, there is real paint on insulating tape! https://www.amazon.co.uk/Spray-Insulation-Coating-Electrical-Transparent/dp/B01G4ABSVY Which is OK but a bit messy, doesn't always stick that well long term and as a result, sometimes you get wateringress through capilliary action. OK for electrical insulation - but not so great for long term waterproofing. I've used this on things like terminals to avoid accidental contact. One thing it's fantastic for is making 'dipped' plastic handles for tools & things. Mechanically, it's very robust. 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 11, 2023 Share Posted August 11, 2023 Depends on the connector - the Lucas ones are not water-tight at all, whereas the Bosch EV1 equivalent has lovely seals inside & for the wires and needs nothing extra. And yes I've checked... Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2023 Share Posted August 11, 2023 One of the things to watch though is the seals in connectors have a rated life. For the commonly used Tyco Econoseal connectors I believe it's only 3 years. I don't know for the Bosch connectors though. Generally, they are long enough for the warranty of whatever vehicle they are fitted to - to encourage unhelpful electrical gremlins after the warranty. Anything you want to last longer - it's worth considering something secondary to keep moisture away from the contacts. Quote Link to comment Share on other sites More sharing options...
Don Del Posted August 11, 2023 Author Share Posted August 11, 2023 23 hours ago, Bowie69 said: I shove vaseline in most of the connections on the car and never have a problem. It needs refreshing every now and then as it has a tendency to dribble out in the hotter places, be interested if there is a high temp version of dielectric grease? The sensor itself is waterproof, so you are only trying to protect the pins from corrosion, you can get waterproof JPT plugs, but they are expensive and can be quite good at keeping water in... I have attached a photo of the dielectric grease I have purchased. According to the spec sheet it is stable up to 400 degrees C which should be more than adequate! 1 Quote Link to comment Share on other sites More sharing options...
Don Del Posted August 11, 2023 Author Share Posted August 11, 2023 10 hours ago, FridgeFreezer said: Depends on the connector - the Lucas ones are not water-tight at all, whereas the Bosch EV1 equivalent has lovely seals inside & for the wires and needs nothing extra. And yes I've checked... What is the part number for the connector? I have Googled it and I came with a Bosch connector with part number 1287013003 on Amazon.com. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 14, 2023 Share Posted August 14, 2023 On 8/11/2023 at 9:43 PM, Don Del said: What is the part number for the connector? I have Googled it and I came with a Bosch connector with part number 1287013003 on Amazon.com. Not sure, DIYAutotune were selling them as "Bosch EV1" and I bought a load because they looked better than the standard Lucas/Durite ones. I don't know if I ever found a real part number - @PaulMc might know? I'd be a bit dubious about buying connectors from random Amazon/ebay sellers as there's about 95% chance it's fake. Quote Link to comment Share on other sites More sharing options...
Don Del Posted August 14, 2023 Author Share Posted August 14, 2023 10 hours ago, FridgeFreezer said: Not sure, DIYAutotune were selling them as "Bosch EV1" and I bought a load because they looked better than the standard Lucas/Durite ones. I don't know if I ever found a real part number - @PaulMc might know? I'd be a bit dubious about buying connectors from random Amazon/ebay sellers as there's about 95% chance it's fake. The one I was looking at is supplied by Bosch in the States. Quote Link to comment Share on other sites More sharing options...
Don Del Posted August 14, 2023 Author Share Posted August 14, 2023 As I have a spare sensor and some old connectors I decided to try a little experiment this afternoon. First off I checked the resistance of the sensor which came out at 403 ohms. I then put the connectors in place and checked the resistance again which was the same as previously measured give or take an additional ohm. The connectors were removed and the opening for the pins in the sensor filled, to create a worst case scenario, with dielectric grease and the connectors refitted. No change was measured when the resistance was checked. To make sure this wasn´t a one off all of the grease was removed and everything cleaned with electrical connector cleaner and the test repeated and the same results were obtained. 1 Quote Link to comment Share on other sites More sharing options...
Don Del Posted August 14, 2023 Author Share Posted August 14, 2023 On 8/11/2023 at 5:40 PM, Don Del said: I have attached a photo of the dielectric grease I have purchased. According to the spec sheet it is stable up to 400 degrees C which should be more than adequate! Quick correction. I have just checked the tin and the temperature range given is -40 to +204 degrees Centigrade. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 15, 2023 Share Posted August 15, 2023 Ta, think I will get a tube then! Quote Link to comment Share on other sites More sharing options...
hario' Posted June 21 Share Posted June 21 yes dialectric grease is for coating connectiors internally, that's why its non-conductive, so it doesn't affect the socket/plug continuity Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 21 Share Posted June 21 To follow up on this, I did get a tube of dielectric grease, it has been great, apart from a bit messy when applying, but no further problems at all. Quote Link to comment Share on other sites More sharing options...
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