4WD tinkering log

I self service, improve and fiddle with my car fairly often at the space and figured this could make for an interesting read. The improvements are somewhat interesting and could be applied to other cars. Some of the failures and general maintenance items are very British which makes them unusually complicated or peculiar.

I also wanted to show that cars with a high computer or sensor dependancy and engines hidden by plastic are still very much owner serviceable. Self servicing and sourcing parts carefully has saved me thousands over a few years and subsidised a nice tool collection.

I will post my upcoming work on this thread as it happens and share some of the historical stuff when I have free time. At some point I will post what lead me to chose this car with some of the pros and cons. Feel free to ask any questions about Land Rover Discoveries, general maintenance and 4WD’ing stuff.

Current to do list / wish list:

  • Drill nine holes in the roof to mount a light bar. (next weekend)
  • Recalibrate the suspension height. (after light bar install)
  • Install a discrete 4G antenna.
  • Replace the navigation module with a chinese Android module.
  • Install an external transmission cooler. (mounted, needs plumbing)
  • Catch up on TSB’s missed since leaving the manufacturer network.
  • Software updates
  • Fabricate some underbody protection.
  • Install some kind of door sill protection for branches and rocks
  • Service the factory air compressor.
  • Adjust the ignition advance and injector duration and maybe changing the cams.
  • Upgrade the peltier element and heat sink on the centre console cooler so it actually cools things.
  • Replace the magic smoke iPod module with an Arduino and Bluetooth chip. (half finished, some issues with Bluetooth chip failing to load config)
  • Install a mute button for the parking sensors; or make something that lets the car detect when an LED trailer is attached.
  • Acid treat and paint patches of underbody rust.
  • CANBUS tinkering
  • Battery isolator for hard resets :roll_eyes:
  • Design a removable snorkel for the side mounted air intake.
  • Brake upgrades (when the current pads are due for replacement)

Completed items to post when I dig up the photos and notes:

  • Auxiliary battery system
  • Roof rails to protect glass roof
  • Torque converter repair and transmission upgrades
  • 3d printed switch panel and 12v/usb outlets
  • Reverse camera
  • Car Configuration File changes that enabled bonus features
  • Tablet mount
  • Dash cam and modem
  • Retrofitted Range Rover bits
  • Oil dump valve and transmission fill valve
  • Trail repairs and damage log
  • Mounted air compressor
  • Slightly larger tyre folly
  • General part replacements; alternator, horns, tensioner, diff breather, wheel bearings
  • Simple, small but beneficial improvements
  • Inspection regime and record keeping for self servicing

Rear coolant line relocation

Recently I fitted new tyres that were 30mm wider and 38mm taller than the default size. While completely legal in Queensland this caused a number of issues:

  1. Speedometer accuracy was altered. - Fixed by adjusting the tyre radius value in the CCF.

  2. The spare tyre would not fit in it’s place. - Fixed by removing a bunch of plastic and partially deflating the spare.

  3. The stability control intervenes far too early and severely on moderate cornering. - This was improved by reducing the suspension height by 19mm to account for the increased ride height of the tyres.

  4. A noticeable loss of performance. - With a naturally aspirated V6 in a tight engine bay my options are limited to cams, tuning and extractors. Something for another day.

  5. The right rear tyre fouls on a coolant pipe during hard cornering - Fix below…

There are two aluminium coolant lines running to a heater in the rear. As they pass through the rear wheel well they stick out a little too far and occasionally contact the right rear tyre.

Normally I would just let the rubbing sort itself out but a leak in these lines can drain the entire cooling system very quickly. I found this out the hard way when a tree branch damaged a small section of rubber hose.

The problem area circled in blue.

All I could find on the issue was this forum post without any pictures and some other forums linking to that post. The best fix appears to be removing or flattening a metal fin and running flexible hose on the deeper side of the fin.

First I removed the wheel, wheel arch, side skirt and wheel well liner to reveal the pipes. Next I removed a section of insulation from each pipe, cleaned the surface with sand paper and marked lines for cutting.

Initially I cut a small notch in the fin which helped me orientate the pipes and estimate the length of the new hose.

First cut.

I used fuel line clamps further up the lines on a short section of flexible hose to reduce the coolant loss. Then removed a section from of each pipe. Immediately fitting rubber hose to prevent leaking.

I enlarge, smoothed, cleaned and painted the notch in the body. Note the existing upwards bend in the heater pipes. I was able to rotate these and set them in deeper by shortening a section of hose further upstream.

Next I set the length of the hoses to give them a gentle curve while keeping them out of harms way. I secured them to the back of a stud with a stainless M8 nut and a pair of cable ties. I applied split tubing to the edge of the notch and both aluminium bends for protection. The fix is now covered by plastic, out of sight and mind.

The tyre will continue to foul on the wheel well liner until the plastic wears away. But the pipes are no longer in harms way.

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Parking sensor mute button

My friends’ Discoveries each have a mute button for the parking sensors. Mine has a blank space for a mute button. The beeping sound gets very annoying when the sensors are coated in mud or when towing a trailer with LED lights.

Before: Missing button and replacement part.

There was no switch mechanism behind the blank so I removed the extra buttons from the new part and placed my old cover over it.



Onboard modem
I needed a modem to enable cloud features on the dash cam. But also wanted some better signal for camping.

The antenna I chose is a Taoglas MA412.A.BI.003 . It sits below the profile of the roof rails for protection without adding to the overall height. It also supports MIMO and does not require a ground plane.

First I removed this cap on the roof and cleaned off the adhesive.

The antenna is secured with adhesive and a M20 stud through the hole. It overlaps the glass panel slightly but the adhesive seems pretty flexible.

Cables were run behind the roof lining to the middle dome light then connected to a 4G MIMO router with the battery removed. Fitted snuggly between the roof lining and structure.

It works pretty well and gets an improved signal of 4 to 10dB over a regular phone. It also manages to get service where regular phones can’t.


Roof mounted LED bar

The factory headlight beam is cut off very low with high contrast which makes it difficult to see hazards and gauge the depth of holes when off road. The high beams create a fatiguing bright spot on trails and don’t really help with illuminating holes. The only reasonable solution was to install a roof mounted LED bar that will one day be worth more than the car.

I choose roof mounted for a number of reasons:

  • Lights through sea spray without causing a bright spot in front of the car.
  • Casts light down into holes.
  • Makes the bar difficult to steal.
  • Almost impossible to legally mount it elsewhere without a bull bar.
  • Protects the light from stones.
  • Protects the glass roof and sunroof from tree branches.

I found if difficult to choose a beam shape and did not want to install multiple LED bars or spot lights. I also did not want to use the typical end mounting brackets. After some research I chose a bar with multiple LEDs mounted at different positions inside 2 lenses. Allowing a choice of 8 beams between flood and spot. As all the sets of LEDs operate together horizontally it is considered to be a single light in Queensland and is perfectly legal. The shape of the body does not produce any wind noise. 42" wide, peak 318 watts @ 26.7 amps, 11 Kg.

The roof rails end too far back which would cut off a lot of light and would add 12cm to the overall height of the car. I opted to mount directly to roof above the windscreen.

I lowered the head liner to choose mounting points that would go through the roof skin to the structure without fouling any wires or the airbag squibs.

I used magnets to hold the mounts in place while measuring and marking.

Holes were punched, drilled, step-drilled, de-burred and painted.

Stainless riv-nuts with Sikaflex sealing. 2 are capped and 2 allow the bolts to go through to the structure.

Mounts installed with a variety of tamperproof stainless fasteners. Some can not be Undone from the outside.

The bar attached to mounts using a variety of tamper proof stainless fasteners. There is no quiet, fast or non-destructive way to remove it.

Power cable through the roof skin with a stainless cable gland. Split tube on the outside to protect from UV and abrasion.

The bar provides some protection for the open sunroof without adding to the overall height.

Fitting the components and wiring was very time consuming. It included a power relay, fuses, control module, GPS antenna, control keypad, high beam relay, override switch and factory aux light switch.

Control module fitted to rear of interior light.

GPS antenna fitted out of sight under the glass roof panel. This enables a feature that changes the beam shape depending on speed. It works okay but can only be used with the keypad and not an external switch or high beam input.

Keypad attached to top of windscreen. This is used to adjust the beam and save presets.

The control module supports an external switch. I purchased the factory spot light switch for a clean install. Land Rover printed the cutting template at a reduced scale so I had to carefully cut out the switch hole in the dashboard.

The switch matches the other controls and dims with the other dash lights. It has an indicator light and is wired with the high beams to comply with regulations. I installed a switch out of reach of the driver to allow the bar to be used as a work light without the high beams or to completely disable it.

Wide beam providing soft light without bright spots.

Medium-spot beam with park lights on providing light far ahead without blinding reflection from sea spray.


Tail light upgrade

The cost of a single replacement tail light for a Discovery 3 in Australia is obscene. It worked out cheaper to buy a pair of Discovery 4 LED tail lights from overseas.

The Discovery 4 lights are a direct fit and look better except for the chrome.

The clicking sound for the LED indicators was annoyingly fast and logged bulb failure faults. This was resolved many months later by adding a resistor in parallel with the indicators on each side.

Pollution sensor
This sensor is used to automatically switch between fresh or recirculated air.

“The pollution sensor allows the ATCM to monitor the ambient air for the level of hydrocarbons and oxidized gases such as nitrous oxides, sulphur oxides and carbon monoxide.”

Sensor fitted with a single stainless bolt that was hard enough to tap itself into a hole in the magnesium frame. The wiring was already there.

Climate control panel replaced with another one that has a slightly different recirculate button.

Enabling the sensor in the Car Configuration File.

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