Ask The Guide

What you haven’t told me is whether your car has an automatic or manual transmission. And that means different things if the transmission has somehow been over-filled.

In the case of a manual gearbox, you’ll find that the extra oil will probably soon be evenly distributed across the bottom of your car as the excess exits the scene through either a breather tube or a seal or gasket.

But if it’s an automatic, the extra fluid could cause the entire transmission to behave strangely, as this type of gearbox relies on the correct internal fluid pressure to select gears, change gears and, in fact, make the car move at all. Again, though, the extra will probably force its way out through a seal or gasket and then you have a much more complicated repair to make.

The best advice is to check the level of the fluid as set out in the owner’s handbook and make sure the level is correct before driving anywhere else.

Noises are impossible to diagnose without actually hearing them. So you need to take the vehicle to a mechanic and get the car to produce the noise you’re reporting. That may involve leaving it overnight or otherwise reproducing the circumstances under which it misbehaves. Experienced mechanics can often tell whether a noise is important or just wear and tear, and act accordingly.

For the record, your mystery noise could be anything from a worn turbocharger, a sticking hydraulic lifter, piston slap, bearing knock or even something as weird as a loose baffle in the exhaust system. All these things can manifest as random and metallic noises, and they range from simple to catastrophic in magnitude.

This is not an uncommon problem with the head unit in a lot of makes and models. Like any other computer-driven piece of equipment, they have a finite lifespan and, once they’re done, they’re usually done for good. That’s why the dealer would be recommending to replace the unit rather than tyring to fix the one you have.

What a lot of people do is that this opportunity to upgrade to a newer, better head unit with better sound, better connectivity and more up to date apps. There’s loads of choice in the aftermarket and you can spend as little or as much as you want. Many owners also use this as a chance to upgrade speakers and perhaps add a sub-woofer or extra amplifier for much better sound. And you’re right; if the original unit died, a replacement of the same type may well have the same problems.

The first thing to do is get your mechanic to drive the vehicle when it’s hot. Arrange a time and then deliver the car at that time with everything up to full operating temperature. Otherwise, the problem isn’t going to show up when it needs to.

While there are lots and lots of things that can cause this sort of behaviour, it does sound like something in the actual powertrain is the problem. That’s because the shuddering goes away when you drop the transmission into neutral and let the vehicle coast to a stop. If the problem was a wheel, a wheel bearing, axle, brake problem or an out-of-balance driveshaft, the problem would continue even though you were coasting.

You may have a problem with something inside the transmission itself, way too much backlash somewhere in the driveline or a problem with the torque converter. Either way, you need to have your mechanic experience the problem or everybody is simply guessing.

This is actually more common than you might think in cars with this type of rotary knob gear selector.

There are a couple of major causes. The first is a blown brake light or brake light switch, believe it or not. Many modern cars are set up so that unless the driver has their foot on the brake, the car won’t move out of Park. If the brake light switch (or sometimes even the brake light globe) fails, the car doesn’t get the message that the brakes are applied and the car won’t shift out of Park.

The other possibility – and it’s not unknown on Range Rovers – is a flaw in the circuit that turns the knob’s twisting action into an actual gear selection at the transmission. A specialist might be able to take the circuit apart and replace the blown component, restoring operation to normal.

Without a make and model, you haven’t given me a lot to go on. But as a rule of thumb, car alarms can go off randomly for a variety of reasons. It could be something to do with a short-circuit in the wiring that controls the alarm, or a fault with the sensors that detect an intruder and trigger the siren and flashing lights. It could even be a family of moths living in the car that take flight and cause the ultrasonic sensors to trip the alarm. Stranger things have happened.

The underlying problem could be with the car’s body computer. This is the computer that controls everything from the windscreen wipers to the dashboard and, where fitted, the security system. If this computer is playing up, you may find all sorts of weird, random things happening, including an alarm that gives false warnings. Even a fault with the switch that detects whether a door is open or closed, can cause security systems to false alarm.

The first thing to try is to disconnect the car’s battery overnight and then reconnect it next morning. This can have the effect of rebooting the computer and returning everything back to normal. It may not work, but it’s definitely worth a try, and it’s free.

This is really backwards, isn’t it? The ice warning is designed to alert the driver to road conditions cold enough for ice to form and cause a skidding risk. But in your case, the opposite is happening and the car thinks it’s freezing outside whenever the temperature creeps up to 28. This would make most mechanics think that the temperature sensor that reads the ambient temperature has gone haywire and is telling the onboard computer lies.

Either that, or the vehicle is selecting the ice and snow driving mode on its own behalf, and that’s what’s limiting your engine speed. That wouldn’t be dependent on the ambient temperature reaching 28 degrees, however. But if the ice and snow driving mode is part of the problem, you could have a faulty switch or even a problem with the car’s body computer. An auto electrician is your best bet.

What the dealer is saying (most likely) is that the fuel pump will be fixed under warranty but there’s a question mark over the condition of the intercooler. They’re probably separate issues. If the intercooler has failed because of faulty materials or manufacture, then it would be covered by the warranty. If it’s been damaged (a flying rock, perhaps) then it won’t be covered by warranty. At which point, you’re liable for the cost of repairs and diagnosis.

The question you need to be asking is why the dealer thinks the intercooler needs to be tested. Is there anything leaking from it? Are there any performance problems pointing to the intercooler being damaged? If not, it’s hard to imagine why the intercooler would need to be tested in the first place, apart from the manufacturer warning dealers of potential failures. Which, again, would point to a warranty issue.

Don’t be afraid to ask the tough question before any work has commenced, and don’t forget that your state motoring club is a good source of legal advice on this stuff.

But you should also know that this model was involved in a safety recall to address a problem with the cooling system where a failure of the plumbing could allow coolant to escape. If this is part of your problem, it would very likely be considered a warranty job.

There’s a range of possibilities here. The first is that even though the battery had enough urge to illuminate the dashboard lights when you turned the key, it didn’t have enough to actually spin the engine to start it.

Conversely, you might also find that there’s a problem with the wiring that takes power from the battery to the starter motor, which would also see the engine refuse to crank. But don’t rule out the obvious stuff like a blown fuse or relay in the starting system.

You might even have a problem as simple as a poorly adjusted switch that prevents the engine from starting if the transmission is not in Park. Try starting it with the gearbox in Neutral and see if that works. If it does, your transmission safety switch is a dud and needs to be either replaced or repositioned.

This can be a bit of a fiddly job and requires you to disassemble the inner door trim to get at the workings within. The problem itself is usually a case of either the glass having delaminated form the metal track it rides it, or the winding mechanism itself has broken or rusted through or structurally failed in some other way.

Once you’ve removed the inner door panel and any protective sheeting under it, you should be able to see what’s failed or fallen off. You’ll need a good torch and perhaps even a mirror to see what’s going on in there as access can be tight.

If it’s a simple case of the glass having jumped out of its metal track, you may be able to refasten it with the correct adhesive. Often, though, it’s simpler and easier to find a replacement glass and track unit at a parts recycler (which we used to call a wrecking yard). If something else has failed, you may need to replace a whole lot more in terms of components, but until you can see what’s what, you won’t know for sure.

The other advice is to not try to move the window via the power window switch. Depending on where the glass is sitting, you may find the winding mechanism will bear on the glass where it shouldn’t and smash the pane or bend something important.