Fitting a tow bar to a Toyota Alphard MNH10 (3.0L V6, 2002–2008) in the UK involves a specific legal procedure that you must address before picking up a wrench. Because these are "grey imports," standard UK towing laws apply differently than for UK-market cars. 1. The Legal Hurdle: VIN Plate & Towing WeightsMost imported Alphards do not have a Gross Train Weight (GTW) stamped on their VIN plate. The Risk: If your VIN plate does not show a GTW (the second biggest number on the plate), your legal towing limit is 0 kg. Towing a trailer in this state can void your insurance and is illegal. The Fix: You must get the vehicle "replated." A specialist engineering firm will calculate the safe capacity and issue a new, legal VIN sticker to stick over the old one. Recommended Specialist: SVTech (UK-based) is the standard go-to for this. Estimated Cost: Approx £150 – £170. Action: Check your VIN plate (passenger door pillar or under the bonnet). If the GTW field is blank, contact SVTech before towing. 2. Weight Limits & SpecificationsOnce legally replated, the 3.0L V6 MNH10 typically has these limits (using an online calculator): Towing Capacity (Braked): 1,600 kg – 1,800 kg (Dependent on the replating certificate). Towing Capacity (Unbraked): 750 kg. Nose Weight (Vertical Load): 75 kg. Note: The rear suspension is soft. If you tow near the limit, the rear will sag. Many owners fit "assister springs" (e.g., from Grayston) inside the rear coil springs to stiffen the ride. Kerb Weight: ~1,900 – 2,000 kg. 3. Mechanical Fitting ProcedureTime: 2–3 hours | Difficulty: Moderate DIY Key Note: The tow bar usually replaces the rear crash beam. You will remove the crash beam and not refit it. Tools: Socket set (10, 12, 14, 17, 19mm) + Extension bars. Torque Wrench (essential). Jigsaw or Padsaw (for bumper cut). Drill with 12.5mm metal bit. Step-by-Step: Preparation: Lower and remove the spare wheel to clear the work area. Exhaust: Detach the rear exhaust rubber hangers. You don't need to remove the exhaust, just lower it enough to work above it. Remove Towing Eye: Remove the factory towing eye (usually held by 4 bolts) from the chassis rail. This will not be refitted. Chassis Access: The mounting points are pre-drilled in the chassis rails but may be covered by tape or underseal. Drilling: Some kits (like Tow-Trust) require you to drill through the outer face of the chassis rail, using the existing inner holes as a guide. Insert Spacers: Crucial Step. You must insert the metal spacer tubes into the chassis rails before bolting. If you forget these, tightening the bolts will crush the box-section of the chassis, causing structural damage. Mounting: Lift the tow bar crossbeam into place (ideally a 2-person lift). Insert bolts loosely. Bumper Cut: Most MNH10 tow bars require a cut on the underside of the bumper (non-visible from standing). Typical Dimensions: 90mm wide x 50mm deep. (Check your specific kit's manual to be sure). Tightening: Torque the bolts to the manufacturer's spec. If not specified, standard ISO ratings for M12 bolts are: Coarse Pitch (Standard): ~102 Nm Fine Pitch: ~111 Nm Reassembly: Raise the exhaust back onto its hangers. Winch the spare wheel back up (check it doesn't foul the new tow bar structure). 4. Electrical Wiring (The "Bypass" Requirement)The MNH10 uses an analogue lighting system, but it is sensitive. You cannot simply scotch-lock wires directly to the bulb holders without a relay, or you risk blowing the lighting control module. Required Kit: A "7-Way Universal Bypass Relay" wiring kit. Connection Point: The best access is behind the Nearside (Left) Rear interior trim panel. You will often find a Blue and White connector block here which carries the rear lighting feeds. Wiring Colors (Guide Only - Always Test with Multimeter): Earth: White/Black Stop: Green/White Tail: Green Indicator (Left): Green/Black Indicator (Right): Green/Yellow Tip: Use a multimeter or 12V test light to confirm these before cutting. Power Feed: You will need to run a dedicated 12V power feed from the battery (front) to the bypass relay (rear), fused near the battery. 5. Critical Consideration: Transmission CoolerThe 3.0L V6 (1MZ-FE engine) is paired with a specific automatic gearbox. The Risk: The radiator cools both the engine and the gearbox fluid. When towing, the gearbox fluid gets incredibly hot. The stock cooler is often insufficient for towing >750kg, leading to gearbox failure. The Fix: Fit an external Transmission Oil Cooler. This is a small radiator (approx £50-£80) that sits in front of your A/C condenser. It is cheap insurance against a £2,000 gearbox rebuild. Summary Checklist for UK OwnersCheck VIN: Is GTW stamped? If No -> Contact SVTech. Buy: Tow bar (e.g., Tow-Trust or PCT) + Universal Bypass Wiring Kit + Transmission Cooler. Install: Remember the chassis spacers and the torque settings (100Nm+). Test: Verify lights and ensure the spare wheel is secure. Oil Cooler For the Toyota Alphard 3.0L V6 (MNH10), you specifically need an Auxiliary Air-to-Oil Transmission Cooler. Do not buy a "standard replacement" transmission cooler from a general parts site (like AutoDoc or Euro Car Parts). Those are usually the stock water-cooled units that fit inside the radiator—they are what you already have, and they are not sufficient for towing. You need an external radiator kit that sits in front of your air conditioning condenser to provide extra cooling. 1. Recommended Kit & SpecificationFor the Alphard V6 towing up to 1,600kg, the "Gold Standard" specification is: Brand: Mocal (highly reliable, UK standard) or Setrab. Size: 13-Row or 16-Row (13-row is standard, 16-row is better for heavy caravans). Width: 235mm (Standard width, fits easily behind the Alphard grille). Hose Size: Typically 10mm (3/8") for Toyota transmission lines (check this on your van before ordering). 2. Where to Buy in the UKOption A: The Specialist (Best Quality)These suppliers sell complete "Universal" kits that include the cooler, hoses, mounting brackets, and clamps. Demon Tweeks (Wrexham / Online): Look for "Mocal Universal Oil Cooler Kit". They are very helpful on the phone if you are unsure about fittings. Merlin Motorsport (Castle Combe): A dedicated race/performance shop. They stock Mocal and Setrab and sell the hose by the meter if you need extra length. Think Automotive (Isleworth): They are the actual manufacturers/distributors of Mocal products in the UK. If you call them and say "I need a transmission cooler kit for a 3.0L Toyota," they can build a kit with the exact right hose barbs. Option B: Budget / General (eBay & Amazon)You can find "Universal Transmission Cooler Kits" for £40–£60. Search for: "Universal Transmission Oil Cooler Kit 10mm". Brands: Hayden or Mishimoto are decent mid-range options. Warning: Avoid the very cheapest unbranded kits (<£30); the hoses are often low quality and can burst under pressure, which would destroy your gearbox in seconds. 3. What to Order (The Shopping List)If you are buying the parts individually, you need: The Cooler: 13-row or 16-row Mocal oil cooler. Fitting Kit: 4x Mounting brackets (often plastic ties that go through the radiator fins, or metal brackets). Hose: 2 meters of high-pressure transmission oil hose (10mm / 3/8" internal diameter). Joiners: You do not need complex screw fittings. You need barbed joiners to splice into the existing rubber hoses coming from the gearbox. 4. Installation TipThe Alphard V6 gearbox lines exit the gearbox and go into the bottom of the main water radiator. Correct Flow: You should plumb the new cooler in series after the main radiator. Route: Gearbox -> Main Radiator -> New Cooler -> Back to Gearbox. Why: This uses the water radiator to get the fluid up to temp quickly, and then the new air cooler sheds the excess heat before the fluid returns to the delicate gearbox mechanics. Correct Flow Positions & Tests For the Toyota Alphard MNH10 (V6), the transmission cooler lines are not consistently colour-coded or stamped "In/Out". Because guessing incorrectly can overheat your gearbox, you must confirm the flow direction physically. The only 100% safe way to identify the return line is the "Bucket Test". 1. The "Bucket Test" (Fail-Safe Method)You need to intercept the fluid after it leaves the main radiator but before it goes back to the gearbox. Locate the Hoses: Find the two rubber hoses connecting the gearbox to the bottom of the main radiator. Disconnect One: Disconnect one of these hoses at the radiator end. Prepare: Place the open end of the rubber hose into an empty bucket. Place a clear plastic tube (or just a finger/rag) over the open metal nozzle on the radiator to catch any fluid. The Test: Have a helper start the engine and immediately turn it off (run for 2–3 seconds max). Identify the Flow: Option A: If fluid spurts out of the Radiator Nozzle, that nozzle is the Feed (coming from the gearbox). The hose you are holding is the Return line. (This is the hose you want). Option B: If fluid spurts out of the Rubber Hose, that hose is the Feed from the gearbox. The radiator nozzle is the Return. Reconnect this hose and test the other one to be sure. 2. How to Plumb the New CoolerTo get the maximum cooling for towing, you should install the new cooler in Series (after the radiator). Correct Flow: Gearbox -> Main Radiator -> New Auxiliary Cooler -> Gearbox Why: The main radiator helps warm the fluid up quickly in winter, and the new cooler sheds the excess heat generated by towing before the fluid returns to the sensitive gearbox mechanics. Connection Steps: Identify the Return Hose using the test above (the one that carries fluid back to the gearbox). Disconnect this hose from the radiator. Connect the Radiator Output (where you just pulled the hose off) to the New Cooler Inlet. Connect the New Cooler Outlet to the original Return Hose (which goes back to the gearbox). 3. Parts ConfirmationHose Diameter: The MNH10 uses 10mm (3/8") internal diameter transmission hose. Clamps: Use proper fuel injection clamps (solid band), not the cheap worm-drive jubilee clips which can bite into the rubber and leak. Top Up: Installing a cooler adds volume to the system. You will likely need to add 0.5L – 1.0L of Toyota Type T-IV fluid (or equivalent JWS 3309 spec). Check the dipstick with the engine running and warm after installation.