100 series petrol Landcruiser fuel tanks.

I have a 182l Long Ranger sub tank fitted in place of the 46l standard. I believe it uses OEM parts apart from the tank. I'm chasing a fuel feed problem from the sub tank. My Toyota manuals have no information on the sub tank installation. I'd like to check the pump and vent systems without removing the tank. First hint is lots of suction relief when the fuel cap is removed. Does anyone have any ideas?
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Reply By: Member - shane r1 - Sunday, Aug 02, 2020 at 21:38

Sunday, Aug 02, 2020 at 21:38
Is the cap supposed to breath? Or other breathing not working? Shouldn’t be a vacuum in the tank I would think.
AnswerID: 632807

Reply By: Member - DOZER - Sunday, Aug 02, 2020 at 21:45

Sunday, Aug 02, 2020 at 21:45
The sub has a pump that feeds the efi pump. If it runs on main but not on sub, look for fuse issue. If not try removing the fuel cap. You can take the fuel cap apart and clean the dirt out of it. If it’s the vacuum causing the problem. Have you had the head serviced on the motor? There’s a valve on the inlet that can be plumbed the wrong way
AnswerID: 632808

Reply By: wooly0005 - Sunday, Aug 02, 2020 at 21:51

Sunday, Aug 02, 2020 at 21:51
So what exactly is the problem?

As I understand it, there is a small pump that transfers fuel from the sub to the main when you switch it on.

So is the pump working when turned on or not?

If it is and fuel is still not transfering then you may have a blocked filter on the pick up in the sub?

Don't forget about checking out the LCOOL (Land Cruiser Owners On Line) forum. You have to join but its free and there is a goldmine of information there about Landcruisers.
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Reply By: RMD - Sunday, Aug 02, 2020 at 22:38

Sunday, Aug 02, 2020 at 22:38
Bruno F
Do you really have a 182L tank in the space where a 46 L tank used to be? Has the sub actually been removed to fit the larger than main and sub OE tanks? They both total 145. 95 +50 I thought.
Like others, I would think the cap should breath one way, If not as Dozer mentioned, the breathing may be through that valve on the engine. If it is an aftermarket tank then it's wall strength would be the only reason the 182 Litres isn't far smaller because of vacuum. In the past I have seen a thin walled flat style car tank reduce from 80 litres to 22 litres. Different fuel pumps though. Best you sort the vacuum issue I reckon.
AnswerID: 632810

Follow Up By: Mikee5 - Monday, Aug 03, 2020 at 17:05

Monday, Aug 03, 2020 at 17:05
The 100s Landcruisers have two tanks as original, a 45 called Sub and a 95 main tank. There is a dash switch with which I can choose to use either tank at will. It is entirely possible to drain either tank and 'run out' of fuel even if the other tank is full. The fuel does not transfer from one tank to the other, they function entirely separately. Hope this helps.
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Follow Up By: Member - McLaren3030 - Monday, Aug 03, 2020 at 20:04

Monday, Aug 03, 2020 at 20:04
Not sure how yours is plumbed, but when I had my 100 Series, my Longranger tank was switched by a switch on the dash, but had its own suction line feeding to the main fuel pump, it did not feed into the main tank. Are you sure the switch is actually engaging and switching the feed to the auxiliary tank, and the wiring plug is still plugged together at the tank? It happened to mine, the plug fell out of the socket at the tank, I had to use cable ties to keep it together.


In order to fit the 180 Ltr. Longranger into the space that was occupied by the OEM 45 Ltr. tank, the spare wheel has to be relocated to a rear carrier on a replacement rear bumper bar. Yes, 270 Ltrs total capacity.


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Reply By: Bob Y. - Qld - Monday, Aug 03, 2020 at 05:18

Monday, Aug 03, 2020 at 05:18
Just googled “Landcruiser fuel tank breather”, Bruno, and scored this photo. There’s a small white valve on the main tank, so may be one on the auxiliary?

Apparently the tank breathes out through this valve & in through the cap........
..or is it the other way lol?


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AnswerID: 632811

Reply By: axle - Monday, Aug 03, 2020 at 08:42

Monday, Aug 03, 2020 at 08:42

I would check that the sub tank pump is getting power, and working, i know my v8 petrol cruiser 100 s failed there, and had to have the change over wiring loom replaced....$.1500.00 years ago!

Cheers Axle.
AnswerID: 632812

Follow Up By: RMD - Monday, Aug 03, 2020 at 09:35

Monday, Aug 03, 2020 at 09:35
G'day Axle,
Seeing you owned one and I haven't, can you possibly fit a 182L in the space the 45L sub came out of? AND still retain the OE main tank? That is what the OP indicated. That would mean total fuel capacity of 277L. Impressive!
A mate of mine has a diesel with original tanks, main and sub of same sizes and there is not much room under there.
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Follow Up By: axle - Monday, Aug 03, 2020 at 09:54

Monday, Aug 03, 2020 at 09:54

My answer would be No, But i do believe there is a after market tank with more capacity that can replace both the toyo tanks... how it fits in there ? dont ask me that!

There was a post a while ago in regard to this , not sure of the out come .
FollowupID: 909702

Follow Up By: Steve in Kakadu - Monday, Aug 03, 2020 at 10:04

Monday, Aug 03, 2020 at 10:04

I have a 180 ltr sub tank in my 200 series, you have to take the spare wheel and its fittings out and the 40ltr sub tank. Then the 180 ltr tank fits in like a glove and should use all the original plumbing and fittings, that's how my Brown Davis one works anyway. The spare wheel ends up on a rear wheel carrier.

As for the OP question, no idea.
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Follow Up By: RMD - Monday, Aug 03, 2020 at 13:05

Monday, Aug 03, 2020 at 13:05
Thanks Axle and Steve.
That clears it up, I too thought all original tanks are removed and the 182 L in place of. Not what the OP mentioned though. What he said mentions removing the sub and replacing it with 182L, but didn't say the main went too. If it is using a "sub tank' System on 182 then it has to be drawing down to a set level and then switching to the last bit called "Sub" but all from the one tank. Really "techo" like all my early motorbike tanks where it is all one but used down to a level and the rest is reserve. Just reach down and turn the lever eh? If one tank only then the breather problem is happening to the only tank fitted. To me a tank problem and not a sub problem. He said a 182L sub tank was fitted. That quantity is hardly a sub tank. A bit confusing, where people have to work out what he means from what he didn't say.
FollowupID: 909704

Follow Up By: Alloy c/t - Tuesday, Aug 04, 2020 at 10:17

Tuesday, Aug 04, 2020 at 10:17
Confusion RMD ? How ? Even in the old 80 series it was a simple job , remove the 'standard' sub tank of 46lt and fit a larger tank by freeing space were the spare wheel normally lived......FYI in the FJ Cruiser upto 2013 there was only 1 tank of 76 lt then in 2013 it came out with 2 factory tanks , the 2nd tank larger at 86 lt , given a 'useable' 156lt all up , many pre 013 have had an 'after market' SUB tank of 136lt fitted giving 200lt useable and needing a 2nd mortgage on the house when time to fillup.....
FollowupID: 909718

Follow Up By: RMD - Tuesday, Aug 04, 2020 at 12:52

Tuesday, Aug 04, 2020 at 12:52
Alloy CT.
I understand the spare wheel and loss of OE sub can make a bigger tank, but the way Bruno has presented it, he still has the OE and even more fuel than a normal added tank, with a much larger tank at 182 + the original. That means if the is trying to find plumbing and pumps etc for two tanks together at 277 L total, the job is not standard as Toyota made it. If not and he only has one tank of 182, the sub delivery system may be arranged in a way of levels to make it work as if it was two tanks. The confusion is, which way around is Bruno's tank system? We don't actually know yet. If it is 277 total then people can work out from their experience what may be happening. It isn't the simpleness of sub removal, it it is the not knowing what he has really got. Maybe he doesn't know.
FollowupID: 909720

Reply By: Member - Bruno F - Monday, Aug 03, 2020 at 16:00

Monday, Aug 03, 2020 at 16:00
Thanks a lot to all who replied to my post. I won't waste forum space with individual replies. It really has helped me focus. To be honest, I'm procrastinating because it's cold here in Rockingham and easier to do research on the net than actually pull things apart!
Yes, I do have a 182L sub tank. The OEM 46l comes out, so does the spare wheel and the Long Ranger tank fits in most of the space. It uses the OEM pump and sender.
I can access the pump (torch and mirror job) and intend to firstly; see if it runs then pull it and check the filter. All evidence points to the tanks breathing in through the cap, I'd like Toyota to confirm that somewhere!
I got lots of dust out of my cap but still get a vacuum when draining fuel from the tank.
The google pic of the main tank vent line is very helpful as I've found nothing in my Toyota manual.
I've just joined LCOOL so will be hunting there for info.
I'll update when I know more.
AnswerID: 632819

Follow Up By: RMD - Monday, Aug 03, 2020 at 20:51

Monday, Aug 03, 2020 at 20:51
So you have 277 litres of fuel tank/s is that correct? A 182 sub and a smaller OE 95L tank. The OE would be the sub by normal measure if that is the way it is. One or two tanks now? By looking at the cap it should be fairly easy to see if it has a one way valve internally. Might even be able to dismantle the cap until any valve is revealed. No need to search the net. Even putting it on your lips and breathing in or out should also do the trick to determine the fact of it. Then you can determine if it is the issue OR further investigation is needed. Pretty simple to do.
FollowupID: 909711

Follow Up By: bobsabobsa - Wednesday, Aug 05, 2020 at 11:58

Wednesday, Aug 05, 2020 at 11:58
Bruno have a look at this link it is from a 105 but the fuel tanks are the same as the


If you look through the thread you will see the fuel tanks and pipe work , ( I learnt a bit to )

It looks to me that the cap is the breather , try a new cap , does it cause a vacuum on the main as well?

The cap is common to both tanks and the filler pipe work has a tank breather returning to the spout from each tank.
I had a look on my 100 and the cap appears to be a breather type,


FollowupID: 909737

Reply By: Member - Bruno F - Wednesday, Aug 05, 2020 at 20:07

Wednesday, Aug 05, 2020 at 20:07
Thanks RMD. Yep, I have two tanks and can carry 277 litres (needed to feed the V8 for long distance remote). I'm now pretty sure that the cap is the only way for air to get into the tanks and reckon mine is OK as the main tank feeds alright. I guess that I'm developing a partial vacuum when draining fuel as the rate is higher than the normal engine consumption. I'll probably shout it a new cap though, a lot of dust has been through the original.
AnswerID: 632831

Reply By: Member - Bruno F - Wednesday, Aug 05, 2020 at 20:12

Wednesday, Aug 05, 2020 at 20:12
Thanks Bob. The link was very helpful. I've learned a lot about the layout already. The cap seems to be the only air inlet for breathing, Mine is OK but I did clean out a lot of dust and grit. I've pulled the pump and checked it's filter, OK. It runs on 12 volts. Next was the shuttle valve, also OK. I guess it's time to delve into the electrickery!
AnswerID: 632832

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