Patrol Tank in a Surf

Sick of the pathetic fuel range in your Surf? I get around 400km to the standard tank with the 1KZTE 3L Turbo Diesel. 450 on the highway, 250 towing a car trailer. After following mates that get over twice that (I hate Land Rovers), I decided to fix the problem. I think it was Toyota’s decision to give the new Prado (same engine) a massive 180 litres, compared to my 55 litres that finally clenched it.

The mega $$$ for the aftermarket tanks was out of the question, although their capacity is definitely excellent. I had seen a guy with a patrol tank in before, and it seemed to fit well. He had a filler under the wheel arch, a solution I found unacceptable. So a sat down and figured out how to make this all work, without a body lift.

Warning

Note: Fitting an additional fuel tank may:

• void your 2nd hand warranty (it’s not worth crap anyway)
• void your insurance
• leave you legally liable
• make your vehicle unroadworthy
• make your vehicle unsafe
• be illegal
• sag your rear suspension
• affect your vehicles handling
• be a fire hazard
• explode

So, if any of the above happens, or anything else happens due to this information, tough luck. It worked for me, but may not for you. Maybe I got lucky, maybe this is the Internet and I am lying to you, maybe I want to blow up all Surfs, maybe I am smarter than you, maybe it’s all an evil terrorist plot (and another place to hide weapons of mass destruction). So, you do it, your problem. All liability absolved. Lawyer types will disagree I am sure, but it will do for you and me.

Click here to leave this corrupt and decadent western imperialist travesty of a site

I decided to follow the Landcruisers that I had dealt with previously and run dual tanks with a changeover switch between them. The option of a pump though system that filled the primary tank occurred, and the pro’s and cons are listed below.

	Pros	Cons
Dual Tank	Totally Separate Systems if fuel is dirty or tank damaged Single Gauge shows current tank No transfer time	Have to leave fuel in both tanks Low levels can be problem on steep hills (fuel flows away from pickup) More pipework and valves Have to buy valves
Pump Through	Can fully empty second tank Less problems on steep hills with low levels in both tanks Simpler piping	No gauge on second tank Have to transfer fuel and monitor pump Significant transfer time Have to buy a fuel pump

• Parts Req’d

• GQ Patrol / Maverick Wagon Fuel Tank (complete with pickup) ($90 from wreckers)
• 1.2M x” Filler Hose (Hydraulic Suction Hose was cheapest)
• 1.5M x” Filler Overflow Hose
• 3M x” Fuel Supply Hose
• 3M x” Fuel Return Hose
• 2 x Landcruiser changeover valves (80 Series GXL Diesel) ($50 from wreckers)
• Mounting Hardware – Nuts, Bolts, Washers, Locktite, Rubber
• 45? filler bend (x” Exhaust pipe)
• 120? filler bend (x” Exhaust pipe)
• 300mm Exhaust Pipe
• Hose Clamps (Various)
• Wiring, Switches etc.

The patrol diesel tanks do not have an in tank pump, as they are suction from the injector pump on the engine. The surf is the same. If you want to do a transfer system you will need either an external pump, or a different pickup.

The hose lengths above are for an install the same as mine. If you choose to different valves, mount them elsewhere, do a pump through setup, etc, etc, you will need different quantities. I chose the cheapest fuel hose I could get, and used hydraulic / fuel suction hose for the filler. It was actually cheaper than radiator hose, and much better rated. It has a large spiral wire inside, so be careful when cutting it. This also makes fitting it onto larger / smaller hoses quite difficult. To fit it to larger hose, lubricate well with oil and push hard whilst rotating it. It will expand slowly and go over. Use only good quality hose clamps to compress the hose. Good quality hose clamps are sturdy stainless, and have large indentations for the thread, not holes in the strip.

The changeover valves are quite difficult to remove from the Landcruiser. The wrecker won’t like you very much after this. They are in the rear up above the rear axle. I don’t recommend doing it yourself.

Costs

• Tank – $90
• Hoses & Clamps – $120
• Valves – $50
• Misc – $50
• Exhaust – $50
• Compliance – $75
• Total $435

Step 1: Line it up.

Two people make this MUCH easier.

Note the fuel stain. I thought this was from a leaking drain bung. Big mistake. Turns out the spot welds for the internal baffles have started to crack. It’s very small. but enough to leak. Bugger.

Step 2: Trim Exhaust and Chassis

Not as scary as it looks. This allows the sender and pickup to sit up in the chassis and give about 1″ more clearance under the tank. If it bothers you too much give it a miss. I preferred the clearance, and just rust proofed the cuts well. I actully didn’t have to trim this much, but it doesn’t really matter. Structural strength is no different as the towbar is much stronger than this stiffener.

Most exhausts will be in the same place as the tank. Time to move it.

Exhaust pic with tank in place

Step 3: New Exhaust

I took the Surf and tank to the local exhaust guy (Ian Diffen) and had him make up a new rear section. I requested mandrels due to the tight bends required, although the rest of the system is just press bend. 90? and over flow better if they are mandrel due to much less compression of the pipe. Under 90? will cope. He had to trim the mudflap to get it where I wanted it, but it clears the tank well. It is actually a tad close to the wheel, but doesn’t touch, so it will be fine.

Note: It makes using the LHS tow point difficult. You may want to work it a little different to allow for that.

Step 4: Modify Tank

Using object of choice (I like a rubber mallet) and a friend, fit the tank where it will mount and find out the high spots that will touch, then lower them 🙂
A bit of judicious thumping at this point gives another 15 – 20mm clearance under the tank. Also give the filler a good touch up till it is more horizontal, rather than the 45? it normally sits at.

Step 5: Front Mounts

I used heavy threaded rod for these. It doesn’t provide a huge amount of lateral strength, although more than I would credit after lining it all up. I used Locktite on all nuts, although NyLocks would be as good. Definitely use some retaining method, as fixing it later could be difficult. The threaded rod was just drilled through the flange in the rear cross member.

Hints:
1. Line it all up well before drilling
2. The rod is different lengths
3. Stay out on the flange, otherwise nuts won’t fit as they hit the cross-member.
4. Yes I had to bend them once they were in, the flange is not horizontal.

Step 6: Weld in rear mount bar

I welded the rear mount to my towbar. Don’t have one, you’ll just have to figure out something else. I’d recommend fitting a towbar to help protect the tank.

Step 7: Rear Mounts

Three high tensile bolts in the rear with rubber to allow a little flex. (Yes it is the old timing belt)
These also provide most of the lateral support.
If I was doing it again, I wouldn’t trust my welding and would have bolted this support bar in. Butt welds have a habit of cracking as the chassis flexes. I am still considering options for this, but it seems to be ok for the moment.

Will update if it falls out 🙂

Pic of both front and rear mounts

Step 8: Mount Tank

Curse and swear till the tank is mounted in place. Definitely another two person job.

Hints:

• Use 2 people
• Use Locktite or Nylock nuts
• Connect supply and return hoses before mounting
• Connect wiring for sender before mounting
• Block off vent hose as tank will be vented through filler to other tank and it’s emissions system.

Pic of installed with hoses attached.

The clear hose for the diff breather you can see is just temporarily tucked out of the way.

Step 9: Filler Hose fitting

I used a 45? piece of exhaust press bend to assist in this spot. I tried without it and it was just about impossible. It’s still not easy. You’ll need to lubricate the fitting on the tank. The pipe has wire inside, so persist, it will go on. As you wriggle it, the wire moves round till it fits. Make sure it is well on, as there will be flex, and this may pull the hose off if it is not well attached. Persistence will pay off.

The filler line runs forward and just fits between chassis and body in the triangular gap at the edge. I moved the wires for the suspension that run through the same gap more to the centre so they didn’t fowl the hose. The hose will get some abuse as the body and chassis flexes, but it is very tough, and should last the life of the car. There is no sharp edges through the gap.

Step 10: Modified Filler

I stole this idea off another Surf member who had similar under his. <insert link here>

Mine is a little different, as I don’t have the body lift, clearance is an issue. I came out at 30? with a piece of exhaust pipe, and them chopped and welded it parallel to the current filler. I also drilled and welded the filler cutout pipe.

I tried using the 80 series tricky changeover valve system, however there was no way to make the cast valve assembly fit. Even with alloy welding and machining it would be quite difficult. This fits, although it is quite tight.

The new filler fills the original tank, with the factory filler going to the new rear tank.

Another filler pic.

Step 11: Connect the Filler Hoses

This is a very difficult job. Be prepared to swear. There is a 120? elbow under the red circle to get around the tight bend. Take your time, it will work. I had to stretch a few things, and it was a bugger to re-bolt, but it will work. There is virtually no clearance so it is very tight work. It would be Much easier with a body lift.

The extra clear hose is my rear diff breather.

Hints: “Tap” the lip on the body away a little to give more clearance. I found a large flat screwdriver and a hammer made a large difference. The sharp edge of the body is a lot less of a problem when folded flat. You won’t get it all, but the bit to the rear near the elbow will definitely move. Means that you can get to the hose clamp on the elbow.

Make sure this hose clamp is on properly, it’s hard to tell. Otherwise when you go to fill the tank, it’ll pour fuel everywhere. Been there, done that.

Step 12: Changeover valves

The valves that come from the cruiser are a nice 3 port type, with 2 inputs and a common output.

They are a slightly larger fitting than any of the other pipework. I ended up using a little oil on the hoses, and heating them up with a hot air gun to get them to fit. This was after much swearing. A diesel doesn’t care about a little oil in the hoses.

Hints:

• Connect wires before mounting
• Lubricate and heat hoses. Careful using too much force as valves are plastic.
• Be careful that hoses, valves and wires will not fowl on suspension, diff or brakes.
• Diff will only go up so far, look at you bump stops to get an idea.
• Check which ports are what on the vales first. There is 2 inputs and a common output. Connect the wires across a 12V battery or charger to actuate the unit. I used unpowered from the original tank, and powered for the new supply.

Another hose & valve pic

I spent ages working out where to mount the valves so they would fit, not be near the exhaust, not fowl the suspension, not go though the floor. I ended up mounting one from the front lip of the rear cross-member. The return valve was mounted to the front lip of the tank with it’s bracket inverted.

And another

Step 13: Connect Hoses

This is where the factory hoses fit on. Send the original tank lines back to the changeover valves. Connect your new lines here.

Hint: Use the factory springy hose clamps on the fuel tank as there is no way to get a screwdriver in to tighten normal ones.

You may have to prime the lines, but mine did it itself. Make sure that you put fuel in the second tank before trying to run on it. If you suck the system dry, you will have to prime it all again, and that’s not fun.

Clearance

Rear View

I think the clearance is quite reasonable, up to your personal opinion.

We took it out to some pretty rough terrain and it was nowhere near to rubbing the ground.

I would like a bash plate under it though. Not too heavy, just something to adsorb any pointy rocks I may come down on or rub over. Similar to the factory fuel tank protector would be fine. I’ll keep looking.

RHS View

LHS View

Results

• Filled it with approx 80 litres of diesel, gives about 75L useable. I’ll confirm when I have a gauge and it stops leaking.
• No gauge, but it was still going at 500KM
• I estimate range will be 1000km now or more with both tanks full
• When it’s empty you don’t know it’s there
• Full, it lowers the back of the car a bit. Mine sits slightly high in the rear unloaded, and slightly low loaded for camping. That is with H/D Kings in the rear. Now when I fill the tank, it sits as if it had a full load on board. I would NOT recommend fitting this with standard springs. Full tank and full load was still quite reasonable rear ride height, just slightly below neutral.
• Handling is virtually no different, full or empty. Little heavy in the rear like a full camping load.

Comments

• These tanks have a bash plate on them in the Patrol. Mine didn’t for some reason. I’ll have to get one.
• I’d normally leave it nearly empty as it is more weight to cart around, this will impact fuel economy, tyre wear, handling etc.
• You obviously can’t mount another spare tyre under there
• The after market tank with 120L would be nice, gives more useable than this one does. Weight and cost a lot more though.
• The after market 110L replacement tank would be better, but is a lot more money, and give less range than this. It is really only an additional 55L on top of factory, where I now have 80L. Ideal placement for additional tanks is between the axles though. Out on the overhangs is a bad place to put weight as it de-stabilises the car. Tanks, bullbars, winches, water, batteries are the heaviest, and always end up out on the overhangs, a really bad combination. Try and minimise this where possible. Store water and jerry cans in the rear footwell for example, it’s central and low.
• I’d use the rear tank up first when going off-road, so as to take weight out of the rear. This will lift the rear a little, and improve weight distribution.

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