Hard call but my policy is if it shows no signs of being a problem leave it alone, you are talking a month long trip to Mexico but is that a month of driving a significant number of KM everyday. Or just a month long trip to Mexico taking the Disco as your vehicle, there is a big difference.

If you plan on driving say 400k a day for 30 days that is 12000k , really not that much mileage even at double that you are at 24000 still not that much. Can stuff go wrong most certainly but that would true no matter what you drive with that number of KM. So my suggestion take spare hoses, headlight and tail light bulbs, a couple of air filters, belt and tensioner and get your fluids changed before you leave and enjoy the trip.

Spending 1000's of dollars because something might maybe fail maybe, means you do not trust your truck at that point I am with Redwhitekat rent or buy something else for the trip, because you will be worrying the whole time your truck will fail, kinda of takes the fun out it.

All the above assumes you are mostly staying near towns and cities, if you are actually spending the entire time in the backside of nowhere then Deputy 's post is very relevant. Braking down in the middle of nowhere in a foreign country, with more limited infrastructure than you are used to is not a good thing.

The only example I can thing of is that I would happily drive my Disco from Vancouver to Newfoundland a trip of about 5200 km each way doing nothing more than and oil change a both ends carrying only the spares I mentioned if I went through the southern part of Canada, if I went north through the Yukon and the old Northwest territories then I would do a far more detailed check of my truck, and very possibly either do the work in Deputy's post or carry the parts, water pump, tensioner, belt, a couple of hubs. I already have hoses.

 

I have noticed that ball joints usually need work around the 150k mark.

 

I wouldn't do it until they leak. But what you can do is change your cooling system over to a motorad 180 thermostat and HD fan clutch. Replace the waterpump if that has not been done.. You can run you temps in the 180's permanently and then you'll never give your HG's an excuse to leak.

 

The radiator and HG in my 2003 Disco failed at 110K and 115K miles respectively. Regardless of whether you change it prior or after the HG failure, the important thing is to make sure to shut down the engine quickly. The continued overheating (after the head gasket blows) may cause further warping of the heads and block. I have an Ultragauge with an alarm pegged at 225-degrees (using a 180-deg thermostat).

What is the current state of your cooling system? i.e., water pump, radiator, hoses, etc? An Ultragauge will help you to keep a constant eye on the temp swings, especially on a long drive to Mexico. It may help you to discern upcoming issues with the cooling system.

 

I have my UG alarm set for 200. It only gets to there if I am half way up a mountain. I have the in-line thermo.

 

buena suerte para encontrar un coche de alquiler que puede tomar en México. Not nearly as safe as visiting our friends to the North... eh?

 

It at least it is is warm in Mexico when you break down, Northern Canada not so much and did we mention the black flies and 4 engined mosquito's.*

But in all seriousness, the one thing I hear a lot of from US off-roaders is they depend on their cellphones.* 1 hour from home and 15 minutes up a primary FSR and there is zero cell service, and I am a whole hour from downtown Vancouver.* As you go east or north the cell service is pretty spotty out side of major centers or hi-ways and some of them are pretty iffy.* So in mentioning Mexico's infrastructure or renting a vehicle, if you do not trust your truck, it is more a case of if you breakdown a long ways from anything and you might have along walk ahead of you.* My record is 600 Km not seeing another person, at the mid point it was about 125 miles to the nearest town, it was tiny, no cell and VHF was spotty.* And I was only about half up the province, no truck problems but stuff can happen.* You need to feel confident in both your vehicle and yourself if you are taking that road less traveled.

 

 

 

If it ain't broke don't fix it