Ask The Guide

Despite your extensive efforts to fix this problem, it appears you still have a situation where the coolant and oil are mixing. No oil should be able to mix with the coolant (or vice-versa) and if it is (which is why you’re seeing oil in the coolant tank) then you have a fairly major problem somewhere in the engine. Check the dipstick. Is the oil in the sump milky and opaque? I’m guessing it probably is, and that’s another giveaway that your engine has a major problem.

Perhaps the cylinder head itself is cracked. Maybe the engine has a split bore. Perhaps the light skimming the head received was not enough and it’s still warped. Either way, the oil and coolant are mixing and that’s bad. The fact that the oil and coolant in the bottle are being forced out of that tank suggests combustion pressure is also playing a part, once again signalling a leak between the oil, coolant and combustion areas of the engine.

The engine in your car uses a rubber timing belt which requires replacement every 90,000km. The design of this engine means a broken timing belt will likely destroy the entire engine, so it’s not something to ignore.

There are three classic causes of a sinking brake pedal. The first is a worn out brake master cylinder that is allowing brake fluid back past the actuating piston. The second is a leak somewhere in the braking system, either a caliper itself or a brake line or union and, the third is an ABS system fault where the ABS pump isn’t working properly, usually due to a low brake-fluid level.

Regardless of the cause, there’s no `acceptable tolerance’ for a brake pedal that slowly sinks towards the floor. A braking system in good working order should be able to hold the brake pedal at the same level more or less indefinitely. Any sinking is bad news and is a serious safety issue. I wouldn’t even have the car towed to a workshop; it’s simply not safe to drive.

Again, a problem like this is very difficult to diagnose via remote control. You haven’t given me much to go on here, but my first suggestion would be to have the car scanned at a workshop and see what error codes materialise. From there, you can take a much more targeted approach to working out which of the hundreds of possible components is causing the problem. Don’t forget the basics, either, such as contaminated or old fuel in the tank. Modern fuel doesn’t like sitting around in a tank and can `go off’ over time.

For reasons known only to marketing departments, the LDV, like most modern four-wheel-drive vehicles, uses a rotary knob to shift between two and four-wheel-drive and high and low-range. While old-school off-roaders of decades ago used a simple, mechanical lever to make these shifts, the modern rotary knob system relies on electronics and solenoids to effect the same shifts. When these solenoids go wrong or there’s an interruption to or glitch in the power supply, you can easily experience the symptoms you’ve noted.

The LDV is by no means the only brand to suffer vague or phantom shifting with this system and a body-computer re-set may be required. The fault has nothing to do with you leaving it in 4H while it was parked for a few days. It’s also very unlikely to be an actual mechanical problem with the transmission. So make it the dealer’s problem; it’s a new vehicle, so the vehicle will be covered by warranty and it won’t cost you anything to have put right.

Modern cars absolutely hate a battery that is not holding charge properly or not fully charging in the first place. If the computer and the various sensors around the car aren’t getting the correct voltage form the battery, they can decide to shut down or go slightly crazy, causing rough running, poor fuel consumption and hard starting (to name just a few symptoms).

A radio playing on a job site really shouldn’t flatten a battery in a few hours, but are you leaving the doors open and, therefore, the interior light on at the same time? That could definitely flatten the battery. The rule of thumb is that you should expect about five years from a battery, so on that basis, yours is definitely a chance to be ready for replacement. Test the battery under load (when cranking the engine) to see how much current it’s delivering under stress.

What you haven’t told me is whether the oil was actually low when the warning light first showed up on your dashboard (and before you topped up the oil). Perhaps the person who changed the oil didn’t add enough oil afterwards; perhaps they didn’t account for the extra half a litre required to fill the new oil filter. Even draining the oil to change it could, conceivably, cause the low-oil light to trigger, and if that’s the case, you need to re-set the light once you’re satisfied that the oil level is correct.

Re-setting this warning light varies from car to car, but an actual mechanic would probably know how to do this, so maybe a quick visit to a workshop to have the light re-set will be worth the small cost involved. By the way, I never rely on warning lights to tell me my engine oil is low. That’s what a car’s dipstick is for. Check it each week and you’ll never run the engine low on oil.

Your situation may be caused any one (or more) of about a thousand faults that is making the car’s on-board computer think that there’s a major problem. In turn, the computer switches the engine to operate on minimal power to make it home without destroying or further damaging any component. A car’s limp-home mode system is triggered by a range of protocols that are acted upon whenever the car perceives a drama. Anything from low oil level to a hot transmission can cause the limp-home system to intervene, and it can be an actual fault or, sometimes, simply an erroneous signal from a sensor that isn’t telling the truth. Have the car scanned and see what error codes are produced.

I’d check both the throttle body, which could need a clean, and the throttle-position sensor (TPS) which can fail or send incorrect information back to the computer. Both these components have a major effect on how a car idles and both can require maintenance or even replacement. Other possible causes could be worn fuel-injectors, a vacuum leak and a huge range of other possibilities. But those are the two I’d investigate first. Once I’d had the car scanned for fault codes, that is.

Did you replace the coolant tank because the vehicle was losing coolant in the first place? If so, there’s a chance that even though the coolant tank is brand new, there could be a leak from somewhere else in the system (that’s allowing the system to lose pressure, as you’ve identified). Possibilities include the radiator itself or even a head gasket, not to mention any one of a number of plastic fittings that control the flow of coolant to the engine and the car’s heating system. But don’t rule out the simple stuff, either; even the humble radiator cap or loose hose-clamp can allow pressure to leak from a cooling system.

The problem with a lot of imported cars is that they tend to use lots of plastic components in their plumbing systems. As they age (and at 16 years old, your car is hardly in the first flush of youth) these fittings and couples become brittle and can begin to leak or even fall apart altogether. In colder climates, these plastic bits and pieces don’t present the same problems to the same degree, but here in Australia, our hot-climate heat-cycles are not appreciated by some makes and models. Combine that with a modern, pressurised cooling system, and you have yourself a problem.