Some Mitsubishi models in the past have had problems with a rough surface on the head-gasket sealing surface of the crankcase,. This has led to head gaket failures and coolant loss. This was fixed by about 2014 with a different machining process at the factory, so this could be your problem.

At the time, Mitsubishi issued a service bulletin for this problem and was modifying cars to fix them. However, whether this bulletin would still apply in 2025 is the big question. However, it would certainly be worth contacting Mitsubishi Australia’s customer service department to see if there’s still assistance available.

Most factory roof bar systems are only designed for light duty stuff and will have a maximum capacity of between about 50kg and 100kg. So, by the time you add your 75kg tent plus whatever humans are going to be sleeping in it, you’d be way over the limit and in real danger of collapsing the whole deal onto the car’s roof panel.

Most people who fit roof-top tents or use that real estate to store things like spare tyres, fuel cans and camping gear, opt for an aftermarket roof-rack system which is much better able to cope with higher loads. Try a four-wheel-drive accessories store in the first instance and remember that to make a roof-top tent as safe as possible, you’ll also need to find a ladder that fits the car properly to get in and out safely.

The good news is the Challenger was and is a popular choice for campers, so you should be able to find what you need on the aftermarket.

Under Australian Consumer Law, all brand-new cars sold here must come with a factory warranty, but it’s up to the manufacturer where to set the time and distance limits for that model. But even the most generous car-maker isn’t going to apply a warranty to a car that is now two decades old and has covered goodness knows how many kilometres.

For reference, most new-car warranties now cover a vehicle for between five and seven years. You will sometimes find a manufacturer will help out with some of the cost of repairs if the vehicle is only slightly out of warranty (and then, usually on a pro-rata basis). And that will only ever happen if the vehicle is question has an absolutely perfect service record.

If your engine has multiple problems, the best advice might be to look for a good, tested second-hand engine and replace the whole thing.