Corrosion Control - Rust Proofing a 2018 Nissan LEAF SL

On the agenda is a the winter to summer tire swap, final drive oil change (no other oil in an EV!), brake service, corrosion management, and trailer hitch install. This is the first hoist for the new to me 2018 LEAF SL, shown here with some rather pedestrian studded winter rims and tires/TPMS sensors that came included as an extra with the car. I'm not a fan of these alloys, but hey, they are fine for winter use. The main topic here though will be removal of the fender liners and under body panels to deal with corrosion control, a necessary evil for our climate here with cold winters and salt/sand used liberally on the roads.

This is my first look underneath since purchasing the 2018 LEAF SL a few months ago. It came from a driving school so was driven almost daily, and came to me with about 36 000 miles on the odometer.



You can see there's not much looking underneath as most of it is enclosed in three plastic belly pans. The front shield has taken a few hits, and one corner will need some repair. There is some evidence of rocker guard (permanent application) in a few areas (under the rockers) but it is curiously spotty..almost like it was a cursory spray by techs who were not concerned about coverage. More pics later on that.



Looking from the back, you can see Nissan has incorporated a few vents on the panels to prevent excessive air pressure between the chassis and panels which would no doubt just blow them out. They are just plastic/fiber.



This vehicle has 58 000 kms (36 000 miles), and is already showing corrosion at the typical areas. More pics later on that. The first two pics are at the front A arm and main motor support sub frame.




These pics are from the rear suspension area:





This rather beefy "Ehitch" is one of the only hitches out there for the later model LEAF with a 2" receiver. It will be used mainly for carrying our mountain bikes, but I also will tow a small trailer occasionally. The hitch is rated to 2000lbs, and 300lbs tongue. I'll run separate power for the tail light kit (also from etrailer) from the 12volt battery up front while the belly pans are removed. I makes sense to do a job like this at the same time as corrosion control as it requires some wiring, and removal of the rear pan anyway.



This pressurised "ProTek" cavity gun has interchangeable tips so I use a collection of wands, and flexible 360 sprayer hoses etc. to cover the hard to access areas. I run it at 60 PSI and with Noxudol there is very little over spray and zero fumes.



I'll be using Noxudol 300 (black, heavier body for chassis) and 700 (clear, penetrates seams etc. for inner panels, or non exposed areas). This material has zero solvents so no fumes, but it does contain a number of chemicals that actively react with rust. It stays flexible, like a wax, and never hardens. After 3 years on our Highlander, it only required a few touch ups on high exposure areas on the chassis, so does not wash off in a few minutes of water exposure, like Rust Check or Krown.

denwood said:

This rather beefy "Ehitch" is one of the only hitches out there for the later model LEAF with a 2" receiver. It will be used mainly for carrying our mountain bikes, but I also will tow a small trailer occasionally. The hitch is rated to 2000lbs, and 300lbs tongue. I'll run separate power for the tail light kit (also from etrailer) from the 12volt battery up front while the belly pans are removed. I makes sense to do a job like this at the same time as corrosion control as it requires some wiring, and removal of the rear pan anyway.

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Maybe a little off-topic question since you mentioned the Ehitch. I have the same one installed on mine, waiting on them to ship the wiring kit as it is back-ordered. From reading the site, I thought it plugged in-between existing lights, but you are saying you have to power the wiring kit from a wire that is run all the way from the front of the vehicle? :shock:

knightmb said:

Maybe a little off-topic question since you mentioned the Ehitch. I have the same one installed on mine, waiting on them to ship the wiring kit as it is back-ordered. From reading the site, I thought it plugged in-between existing lights, but you are saying you have to power the wiring kit from a wire that is run all the way from the front of the vehicle? :shock:

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There are two different kinds of trailer wire converters: those that use the car's lighting circuits as the source of power for the trailer lights, and those that only use the car's lighting circuits as switching signals and use a separate 12 V wire to power the trailer lights. The latter type is recommended on the LEAF, as it does not increase the current load of the car's lighting circuits when a trailer is connected.

I switched to the separately-powered trailer light converter on the old 4Runner and it also really improves the function of the trailer lights. They're brighter and come on and off more quickly (incandescent bulbs). The trailer lights were kind of dim and "lazy" on the previous converter, which used the vehicle light circuits for power.

Prairie, Knight..yes, I'm just running 12V power back to the trailer hitch harness. I'll post a few pics. I know on my Audi, the CAN bus communicated voltage on the lighting system, so my guess is the LEAF is the same. This means just connecting a wiring harness to the rear lights would likely set off a code. The other issue with some cars that have LED lights, (and trailer lights that may or may not be LED) is that the car's electronics may not like having another set of lights added in. If you use a trailer wiring harness with a separate 12 volt power supply, you avoid any of these issues.

denwood said:

Prairie, Knight..yes, I'm just running 12V power back to the trailer hitch harness. I'll post a few pics. I know on my Audi, the CAN bus communicated voltage on the lighting system, so my guess is the LEAF is the same. This means just connecting a wiring harness to the rear lights would likely set off a code. The other issue with some cars that have LED lights, (and trailer lights that may or may not be LED) is that the car's electronics may not like having another set of lights added in. If you use a trailer wiring harness with a separate 12 volt power supply, you avoid any of these issues.

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That's what I did with my previous Leaf, wired directly into the lighting in the back and replaced all the trailer bulbs with LED. Didn't set off any codes and the lights were so bright I thought it might cause someone behind me to have an accident when I stepped on the brake pedal :lol: But I do appreciate the time to post up so much detail about them, I'll stop hijacking the topic now. :mrgreen:

Knight, no worries on hijacking That's exactly my setup...LED trailer lights. They are much better than the incandescent bulbs. Maybe I'll fire up another thread specifically on the hitch/wiring install and leave that stuff out of this thread for google purposes

This is a bit surprising due to the quantity and size Of the sand and gravel caught. There are five underbody panels, and this is the fourth, just in front of the rear axle. It is also shielding the back of the battery pack so eventually this area will be packed with sand/gravel in direct contact with the battery casing. The gravel is likely ending up there as a result of openings to the rear wheel wells. I always take note of areas like these as they point to future problems as wet sand stays in contact with body panels. I had to replace a fuel filler neck precisely for this reason on our CRV.



Some mud/splash is evident on the driver side, rear battery case, entire corner, via a gap in the chassis shield. It’s not a lot, but was obvious in that one area. Rocks in an exhaust shield close to the body were the cause of a weird rattle that drove me bit batty on our CRV. I would not be surprised if a few LEAF owners are seeing the same from this shield area.

Aside from the battery mount bolts, most of the fasteners on the chassis seem to be be non-plated and are showing signs of rust. The rear bumper to shield fastener was seized already :-(. This is typical of what I’ve seen under more recent cars, and the trend does not bode well for future repairs, with no corrosion management. Recent Toyota, Audi, and now the LEAF are showing signs that manufacturers are cutting costs by not using plated fasteners on the chassis.

Yikes.

On the hitch project, it's a pretty simple install. No drilling, grinding or mods required.




I ran the 12 gauge power wire for the trailer harness on the drivers side, over the high voltage pack in plastic looming which allows it to route to the 12V battery completely under the belly panels. I just used a wire fish to pull it through. I figure this is much easier than routing via the cabin.

On the corrosion side of things, these images are pretty much a guide to accessing the inner fenders, door cavities, sills, hatch, and cowling. To remove the tail lights, remove the 2 10mm bolts (in the hatch opening) and give the lenses a gentle shove directly backwards. They have sliding clips, so do not try to pry the light out at all!! I have an assortment of flexible and solid rod attachments for the cavity gun with 360 spray heads to cover the inner panels. Your typical Krown or Rust Check "tech" will do none of this, and therefore miss these areas completely. They do not remove chassis shields either. This is why I gave up and them and bought my own gun. It's paid for itself many times over.

denwood said:

On the hitch project, it's a pretty simple install. No drilling, grinding or mods required.

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Yeah, Torklift makes an awesome hitch. I had one on my 2013 and just put one on my 2020, those things will outlast the car :lol:

I ran the 12 gauge power wire for the trailer harness on the drivers side, over the high voltage pack in plastic looming which allows it to route to the 12V battery completely under the belly panels. I just used a wire fish to pull it through. I figure this is much easier than routing via the cabin.

On the corrosion side of things, these images are pretty much a guide to accessing the inner fenders, door cavities, sills, hatch, and cowling. To remove the tail lights, remove the 2 10mm bolts (in the hatch opening) and give the lenses a gentle shove directly backwards. They have sliding clips, so do not try to pry the light out at all!! I have an assortment of flexible and solid rod attachments for the cavity gun with 360 spray heads to cover the inner panels. Your typical Krown or Rust Check "tech" will do none of this, and therefore miss these areas completely. They do not remove chassis shields either. This is why I gave up and them and bought my own gun. It's paid for itself many times over.

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Once again, awesome pictures and detail. Where I live, we don't get the kind of deep winter weather, but looking at the pictures, makes me curious to just take them apart to see how it looks underneath everything.

Ok, question time! The picture that showed all the gravel build up. Is that something someone could flush out with some high pressure water to get the gravel and salt out (for those that don't have a car lift handy) or is all that gravel just buried in there where you have to take off the under shields to reach it?

Oh, another question! Since you already had everything taken apart, did you notice if the tail lights and such are LED or is Nissan still using incandescent bulbs in there for like the brake lights, turn signal, etc? I replaced every single light on my old 2013 with LED (back in 2013) and never had any trouble with them since. Just wondering if my future will entail replacing some burn out incandescent bulbs in the rear (or front?) :shock:

Thanks Knight. The tail lights on the 2018 SL look to be standard bulbs for turn and reverse, but are LED for running and likely stop. There is one LED driver connection under what looks like a bulb port at the centre of the lens. I have the 12 volt battery disconnected but will confirm later. The tail light lens is about 30 seconds to remove ..just remove the two 10mm bolts, and gently shove the entire lens rearward to slide it free of the body clips.

On that panel, it's just a few bolts and clips, so would be very easy to drop. I figure that is the most effective way to clean it every 3-4 years of ownership. The car lived mostly on pavement (driving school car) so what you see in that panel is likely a lot of road sand. If you fire water in there, you'd likely just wash the sand/gravel further along the belly pan. There's also the high voltage battery connections a bit ahead of the panel, so I'd avoid water there

You'll likely break some clips, but I ordered a replacement ( bag of 100 via amazon ($16) ) that were inexpensive and seem good quality. A few of these 8mm clips (spares if you brake a clip) and a 10mm socket is all you need to pull all five belly panels. The clip OEM part number is 01553-09321.

Btw a new front belly pan is $240 CAD from the dealer..so I'll fix mine. It's worth about $20 in my opinion

denwood said:

You'll likely break some clips, but I ordered a replacement ( bag of 100 via amazon ($16) ) that were inexpensive and seem good quality. A few of these 8mm clips (spares if you brake a clip) and a 10mm socket is all you need to pull all five belly panels. The clip OEM part number is 01553-09321.

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Thanks for the link on the clips, it's a much better deal than the local auto store and I end up using a lot of those when doing stuff for friends, so a bag of 100 is awesome!

denwood said:

Thanks Knight. The tail lights on the 2018 SL look to be standard bulbs for turn and reverse, but are LED for running and likely stop. There is one LED driver connection under what looks like a bulb port at the centre of the lens. I have the 12 volt battery disconnected but will confirm later. The tail light lens is about 30 seconds to remove ..just remove the two 10mm bolts, and gently shove the entire lens rearward to slide it free of the body clips.

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Great! Time to order some new bulbs, can't wait to have reverse lights bright enough to make it look like day time (like I had before, LOL) and turn signals so bright, you can see the reflection around the entire intersection at night :lol: You can tell, I like to be safe when driving at night, especially when backing up!

Knight, I figure a lot of margin is generated by body clips at the dealer and parts stores.

Post your LED bulb specs Does the LEAF handle the LED bulbs without spitting any codes?

denwood said:

Knight, I figure a lot of margin is generated by body clips at the dealer and parts stores.

Post your LED bulb specs Does the LEAF handle the LED bulbs without spitting any codes?

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It worked fine for my 2013, the secret was the bulb had to use enough power to avoid any codes or make the blinkers go fast (like a bulb was burned out), but I will have to hunt down (dig through years of e-mail) those bulbs I bought nearly a decade ago. I have a 2020 now

knightmb said:

denwood said:

Knight, I figure a lot of margin is generated by body clips at the dealer and parts stores.

Post your LED bulb specs Does the LEAF handle the LED bulbs without spitting any codes?

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It worked fine for my 2013, the secret was the bulb had to use enough power to avoid any codes or make the blinkers go fast (like a bulb was burned out), but I will have to hunt down (dig through years of e-mail) those bulbs I bought nearly a decade ago. I have a 2020 now

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They make special LED bulbs that have resistors to simulate the load of an incandescent bulb in the car...look for a CAN bus LED...here is a good place to shop https://www.superbrightleds.com/cat/led-vehicle-replacement-bulbs/filter/CAN_Bus,Yes,116,4017:

Learjet said:

They make special LED bulbs that have resistors to simulate the load of an incandescent bulb in the car...look for a CAN bus LED...here is a good place to shop https://www.superbrightleds.com/cat/led-vehicle-replacement-bulbs/filter/CAN_Bus,Yes,116,4017:

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You just saved me looking for the site when I looked at it, was the same place I found my original LED replacements!

More work on the LeAF today, including servicing the brakes (one caliper pin stuck after just 3 yrs!), changing the final drive oil, finalizing the trailer hitch wiring, and removing the rear fender liners.

The front chassis shield needed some repair so I did this with some 6oz glass cloth and West System Epoxy

The rear shield corner needed fixing up. This is before grinding to shape after curing.


The front shield needed 5 small repairs.


Rebuilt the entire (missing) corner on the engine chassis shield.


The LEAF has all of 5 shields to protect the underbody and improve aerodynamics. I gave them a quick wash..


I used a drain port in the hatch floor to run power to the trailer harness, and run the trailer wiring out to the hitch. A fused 12V power lead had to be run all the way up to the 12V battery in the engine bay.


This stuff is super handy for sealing up grommets among other things...




Looking up in the rear fender with the liner removed:

Thanks for all the great pictures and information! Yes, I love the liquid electrical tape, that stuff is so handy! :mrgreen:

Knight, you’re welcome. More pics to come.

Gravel/sand removal is going to be tough. The only place that a hose might work is a gentle stream run from front to back via the air vents on the rear shield. Sand was piled up in there, but there are drain holes. If you run water there the sand can’t migrate...it can only be carried out the drain holes. I’d also run a hose into the rear chamber in the mud guards for a minute or two each.. These were packed with sand as well. This LEAF has about 60 000 kms (36K miles) and has pretty much been only city driven, so someone on dirt roads will be worse.

The model3 chassis shields are worse..I’ve seen a few pics.