Hi Chris,
Welcom to the best, friendliest, and most informative Land Cruiser club in the world.
As Andrew said, there is 1 or 2 or 3 weak spots on the 90 series.
I think, In order of wallet wacking, this is where they stand.
1/ They (Toyota) in a unusual moment of planning have used the main front water radiator, which cools engine water, well they also use it to cool the auto transmission oil for the auto box at the same time. - Not a good idea.
Bit of a stupid idea, it really is.
The term "Oil and water don't mix", well, on a 90 series they do.
What happens over time, and this can be hard to determine when, is that the cooling water breaches the transmission oil lines in the radiator, and the engine cooling water is forced into the auto transmission box.
It is salvagble, if caught very soon, like same day soon, but generally other than that, it normally wrecks the auto box.
Auto boxes work better with oil, and not so good with hot engine cooling water.
2/ The second expensive blunder is the cylder head.
It appears that this is at a terrible risk of distorting when the truck does some hard work. It doesn't affect all, but when it affects yours, it is a real wallet kicker.
There is a feeling that Toyota have put the engine water pump and thermostat in, the wrong way round, ie, they put it in down stream of the hot water instead of up stream of the hot water, or the other wat around.
This apparently causes a time delay in opening the stat, this time delay may be the reason for cooking the head, maybe, maybe, maybe.
3/ The other issue that Andrew mentioned, the locking actuator on the rear diff, , isn't as wallet crunching as the other two, but it is an "inconvienience"
As many of these Land Cruisers don't really get much chance to go off road, then what appears to happen is two things.
A/ The actuator corrodes and becomes useless, which can for sure happen to any LC 90.
B/ The actuator siezes up inside because it has not been used, the addage "use it or lose it" I guess is a good saying.
Another thing that I could suggest is that you have a good look at the rear lights in the bumper.
This is a great place for tones of mud to hide, and over time, the mud just eats away at the back of the lights housing, to replace isn't that much, I think I read that they were about £80.00 for a new pair from a "NOT Toyota" source.
I am sure I have made a few errors in ths post, and many more guys with vastly more knowledge than me will put in the corrections,
Gra.
Suggest you check that the rear diff-lock actuator is working (i.e. when you switch the locker on the light goes solid on the dash) and, assuming it's an auto, check that the gearbox changes are smooth and the coolant in the radiator looks clear (Toyota coolant is red). Obviously there should be no signs of bubbling in the rad when running the engine. As you may have read, one of the few potential problems with this model and engine is that they can crack the head of overheated.
