I wonder if he looked at the dielectric grease before he applied it. Dielectric means it insulates from conductivity. I always do this kind of thing with anti-seize compound because it has lots of metal in it. But I wouldn't do this in any case. I'd run a cleaning tap down the threads to be sure there is no paint in the threads, then put anti-seize on the bolts and save all the paint to protect from corrosion as it was intended. Every bare metal spot he has will now corrode and will be less conductive, especially with the dielectric grease.

But hey, what do I know? I've only been doing electronic work since 1973...

 

Heh, I remember reading this thread when it was first posted and thinking to myself I've had my GSF since November 2017 and never had issues. Well, the last 3 days I've had to jump start my car and even had to push my car out of my garage once, thereby having to manually shut off ebrake..

My car sits for about a week before I drive it. It's not my daily driver and never had issues until this week..

I've only driven my car about 8,000 miles in a year and half and my nearest dealer is 90 miles away. Darn it..

 

BTW, discovered this while looking up some other stuff on TIS - L-SB-0093-11. This LSB is instructions to correct intermittent starting on IS and GS models from 2007 to 2011. The instructions advise the tech to remove the ground from its connection under the steering ECU, run a 6 x 1 metric tap through the threads on the weld nut to clear out any paint, and install a new bolt to hold the ground wire. That's pretty much exactly what I do with ground connections except I hit the threads of the bolt with copper antiseize compound to enhance conductivity and reduce resistance.

 

Wow, just saw his battery video. Paint is there for a reason like you said. This is probably just as bad as his brake job video where he sanded down his brake rotors.

Copper is very conductive which is why it is used in practically every single electric component and would work completely fine in this situation like you said involving anti seize compounds since I believe many are copper/aluminum based. Sure you could increase the electrical potential by removing the paint since paint can decrease electrical potential but rust decreases electrical potential by a much more substantial amount than paint ever will. I remember in my lab experiments in my undergrad where we would test electrical potential between different metals. Rust was often a major factor in trying to measure voltage and killed my experiments completely. I had to sand down rust constantly to get good readings every week. I imagine this guy will have to keep sanding down that area if he keeps his car long term. Paint doesn't kill electrical potential, rust will. I have a STEM degree related to physics but what do I know?....

EDIT: Also, correct me I'm wrong but, doesn't car paint have metal properties in it anyways? So paint is actually conductive in some ways. So sanding down the paint was unnecessary to begin with.

 

In most applications you want paint/powder coating to act as an insulator, engine bay included. The grease/potential surface rust will not really be a factor with ground contact. The bolts in the threads that hold the grounding strap to the body are the ground contact, not the strap to the body itself as evidence by Lexus painting both in the first place. In this case if anyone wanted to improve ground connection the most they should do is use a lock washer with the bolt, nothing more.

I work daily with mechanical/electrical engineers and manage a team of engineers that work in datacenters with large enterprise racks that use 120Amps (2x60A circuits). The racks are powder coated over every inch for insulation and are grounded to the DC through a grounding wire connected to only a single bolt in a thread with a lock washer, that’s it and really all that is needed.

 

Grounding a rack is for safety. You just need a wire big enough to trip the breaker, not carry the full 60A for any significant period. A 10 or 12 gauge bare copper would do just fine for that. The ground strap on your engine gets a ~300+A spike every time you hit the starter, maybe more depending on how cold it is and how thick the oil is. Even a few milli-ohms can make a difference at that kind of current - when i =300 and you want power, you're multiplying by 9000 right off the bat, 50 m-ohms is 450W. The starter motor is rated at 2kW continuous, so even after inrush is over, you're still seeing ~160A in the circuit for as long as it take to start the engine. So I can see the issue if the threads on the weld nuts still have paint in them, because the weld nuts are transferring the current from the bolts to the entire body structure and all the other (many) grounding points where the harnesses are tied down. Lexus acknowledged this with their LSB.

I just can't see exposing all that metal to atmosphere when all you need is clean threads in the weld nut.

 

Agreed, clean threads is all you need. We see it all the time on enterprise racks, they powder coat them and it get everywhere, including the threads and has to be cleaned out before grounding, the same can easily happen on the body of a car before they assemble it.

 

2016 GSF bought the car as CPO last year of Oct and they put a new battery replacement because of failed battery test. and after 8 months of ownership battery died again last week of May and I had to jump the car sitting from my garage.I went to the dealer and they replace it with a new one under warranty..so 3 battery in 3 years..btw I only use my car once a week and it's a very short trip like 20miles back and forth. right now I'm using a battery trickle charger just to maintain it's health. Car have 14.5k in ODO

 

Good for you .. Sounds like you had a better Dealer experience than I just did....
I just picked up a 2016 GSF 2 weeks ago... It was L certified and still has 1 year left on it’s Original warranty.. It was driven by the last owner very little...just 5k on the clock... Bought it.... & I was doing my routine check on the car at home and placed my charger maintainer on it... notice that it took 3 days to bring the battery back? Figured it’s was just low.. So after a few short trips to stores during the week put it back on the charger ... It took 2+ days again to bring it back... It’s not holding a charge is my guess... So here’s were it gets interesting, took it to my local Lexus Dealer in Escondido Ca. They wanted 50 bucks to run the battery check.. I said you got to be kidding me? I’ve bought 3 Hi end Lexus cars in the last 10 months cash, a RCF, a GS 350 F Sport and now a GS-F all be it from multiple other dealers... but they have worked on my cars and have me in there databases... The advisor told me nothing she could do, and maybe I should go to the dealership I Purchased the GS-F from and they can check it. Lets see , she won’t check a car that’s under warranty without a charge???? Thats it... I pulled my car out of there service line, and took my wife to lunch ready to chew nails.... next day I took it down to my local Battery Plus’s store for a free load test... It just barely passes as good... So now I’m just going to wait it out a bit before Lexus gets there hands on it ... again..

 

wow your car is certified and it should be under warranty..I guess it's not about the dealer but a person whos handling the customer's issue..I have a good dealer honestly and all of the service advisor that I talked to always take care of my concern.Like last week I have my tail light by the trunk it has condensation inside..they replaced it right away..thought that they are just going to put a new seal and clean them but they order them right away and install a new one. but anyway yours is still under warranty and they should replaced it if it fails the test.