Ford Falcon Engine Problems

Oil manufacturers recommend a 10W-50 semi-synthetic oil for this engine. But not just any 10W-50. Crucially, the oil needs to be formulated specifically for LPG engines which have different combustion by-products and, therefore, require a different additive package in their oil compared with a car running on petrol or diesel.

Your car has covered quite a distance, but modern metallurgy and engine design suggests that 330,000km is not too many kilometres these days, and the engine could have plenty left to give. If it's starting to use a little oil between services, you could consider going to a slightly thicker grade of oil to compensate, but make sure it's still specifically formulated for an engine running on LPG.

The reason the car overheats under load or when travelling uphill is simply because it's defying gravity and, therefore, doing more work in those circumstances. Think of it as a person using a staircase. They'll go down the stairs easily, but they'll sweat more going up them, and more again going up the stairs with a suitcase under each arm. In a car's engine, hauling a load or driving uphill requires more throttle which, in turn, injects more fuel into the cylinders. And more fuel burned equals more heat. It's as simple as that.

If you've replaced the radiator, water pump and thermostat, you've started logically enough, but simply replacing bits and pieces is not the way to proceed as you've already discovered by replacing parts that were probably good (and didn't fix the problem). You could have a collapsed radiator hose (Were these replaced, too?) or a problem with the fuel-air ratio which can make a car run hot when it's under duress. The steering column sounds unrelated, but if the wiring to the dashboard was damaged during this process, it's possible that the temperature gauge is reading incorrectly and the engine may not be running hot at all. An electronic scan will be able to check the actual running temperature as well as uncovering any fault codes the computer has logged.

Don't rule out things like a build up of debris inside the cooling passages in the engine that could be blocking the flow of coolant. And a check of the radiator overflow bottle is a good idea. These have been known to perish and crack on Falcons, allowing some coolant to escape, leaving you with a low radiator level when you need it most.

A good multi-grade oil is what you’re after; one that is thin enough to circulate and protect quickly in cold conditions, but also able to cope with the heat and stress inferred by a turbocharged engine in hot conditions. Options include a 5W30 oil or even a 10W40, but make sure that the API rating is suitable for your car. The correct API rating ensures that the oil is of a sophistication in keeping with the technology in your engine.

The other critical piece of advice is to use a quality oil from a reputable brand. Ignore the supermarket-shelf stuff and, if you’re having the car serviced at a workshop, don’t forget to ask what brand and grade of oil it intends to use. A fully synthetic oil will cost more but will offer more protection for an engine such as the hard-working turbomotor in an XR6T.

An engine that runs well when cold but misfires when It’s warmed up is often a victim of poor air-fuel mixture. That can be caused by an air-leak (such as the intake manifold gasket you’ve already changed) a crack in any of the intake plumbing, faulty fuel injectors, a worn fuel pump, a corrupted ECU (computer), blocked fuel line or about a thousand other things.

But in this case, knowing the Ford AU Falcon’s engine, I’d be taking a close look at the ignition system, specifically the coil pack. These have been known to fail regularly, often displaying their problems including a rough idle, once the engine has warmed up; precisely the symptoms you’ve noted. That said, rather than rush out and buy a new coil pack, have the vehicle scanned electronically to rule out any other potential source for the problem.

You need to keep using an oil that is compatible with LPG as this fuel places different stresses on the lubricating oil compared with an engine burning petrol or diesel. Provided you stick with the correct grade and API rating and choose a known brand (not the Brand-X supermarket stuff) you should be fine. Don’t forget to change the filter every time you change the oil.

A miss is fairly common on these engines and is usually tracked back to either a dud spark-plug or a crook ignition lead. If you’ve already changed the plugs, I’d suggest checking the ignition leads for excessive resistance. The other major source of misses in these engines is usually a fault with the coil-packs. Swapping these for another set is a pretty easy way to check whether they’re the culprits. Don’t forget, however, that a miss can also be fuel or mechanical-related, but experience with these engines shows that the ignition system is often the cause.

According to government websites, the 2001 Falcon six-cylinder can, indeed, use E10 fuel. You may find, however, that you use a little more E10 over 100km than normal unleaded, so the savings at the pump might not be as marked as they seem on paper.

If you can’t see coolant on the ground where the car has been parked, you need to start a more thorough investigation. Your car is now 17 years old, so every hose, clip, clamp and junction that carries coolant is a prime suspect to be the cause.

The lack of any evidence could mean that the coolant is only disappearing when the engine is running and/or the engine is hot and the coolant is under pressure. So a close check of things with the car up to temperature and idling is a good start. Don’t forget, though, that a running engine has all sorts of belts and fans to get tangled in, and that the coolant – if it is spraying out anywhere – will be scalding hot.

The other possibility is something to which Falcons of this era are a bit prone. And that’s a faulty transmission cooler which can fail internally and allow the coolant to escape into the automatic gearbox. At that point, the transmission is usually damaged to the point of needing replacement, so it’s a big deal, but it could explain the mystery disappearance of your coolant.

As for the central locking, these functions are handled by the car’s body computer. Again, it’s common with this model Falcon for the computer to start playing up and require replacement. But before you do that, check that the battery in the remote unit hasn’t gone flat. If it’s not that, a trip to an auto electrician is the wise move. But if both the body computer and the transmission need replacing, you might just find that the repairs will cost more than the value of the car itself.

Computer-controlled engines like the one in your Falcon, Tony, require a range of sensors to provide the information to the computer to allow the engine to run properly. If just one of those sensors sneezes, the engine can shut down without warning.

As well as a throttle-position sensor, there are also camshaft-angle, crank-angle, air temperature, coolant temperature, oxygen sensors and more. So the best advice is not to start replacing the sensors one by one, but to have the computer interrogated electronically. The computer will be logging problems as they happen and should be able to tell you exactly which sensor is nodding off intermittently. A Ford dealership along with many independent workshops will have the computer-scan gear to do this. It will save you time and money in the long run.

For what it’s worth, since the car cuts out completely, my hunch would be the crank-angle sensor is overheating. So, if you want to persist with a home diagnosis, try this: Carry a bottle of cold water in the car. Then, the next time the engine cuts out, pour the cold water over the crank-angle sensor. If the car suddenly restarts, you’ve found your problem.

But to be honest, you could also be looking at a dud fuel pump, a blocked fuel filter and literally a hundred other possibilities.

There’s no issue with the chain, they rarely break, but they can wear over time. If it does wear it usually becomes noisy, which in itself is not a problem. If it gets too bad the timing can be affected, and it’s best them to replace the chain.

Check the system to see which LPG company developed the system for Ford and take it to them for checking. If you are unsure which company made it contact Mercer Industries (03 8788 1000).