Ford Focus (Mk2: 2004-2010)

Powershift transmission failure

Powershift is Ford’s brand name for their dual-clutch transmissions, designed for Ford by Getrag.

A dual-clutch transmission is like an automated manual transmission. It has two clutches – one drives odd-numbered gears, and the other drives even-numbered gears.

The trick to achieving quick gear changes, that dual-clutch transmissions are known for, lies in pre-selecting gears and predicting driver’s behaviour.

Dual-clutch gearboxes are also very efficient because they don’t have torque converters like traditional automatic transmissions.

You might have heard about the problems (followed by class-action lawsuits) with Ford’s Powershift dual-clutch transmissions. However, all of that applies to Ford’s dry-clutch variant of the Powershift.

There were two types of Powershift transmissions:

• MPS6 (wet clutches) – it became available in the Mk2 Focus after the facelift in 2008. To be specific, it was the 6DCT450 model that was rated at 450 Nm and used in diesel-powered cars.

• DPS6 (dry clutches) – this one came to the market after 2010, and because of the lower torque limit, it was used in petrol-powered cars. The 6DCT250, used in the Mk3 Focus, is the problematic one.

While the 6DCT450 (MPS6) used in the Mk2 Focus may have a decent track record in terms of reliability, it’s still a very complex piece of kit.

I keep repeating myself every time I write about dual-clutch transmissions, and I will this time too. I don’t recommend buying used cars with dual-clutch transmissions. It’s not something you want to own outside of warranty.

If the transmission fails, you will have a problem.

Trying to fix a faulty Powershift gearbox will most likely be expensive or very expensive, which is the norm for dual-clutch transmissions.

A failure of an individual component, like a £20 sensor, or a £30 valve, means that you may have to replace half of the transmission. Sometimes, you can have the faulty part replaced if you can find someone capable of doing it, but it will still be expensive because of the labour involved and the knowledge required.

Few places can repair dual-clutch transmissions and even dealerships do not generally repair them. If you go to the dealership with a faulty Powershift transmission, the odds are that they will offer to replace the entire transmission or at least the mechatronics unit (valve body). The latter is the cheaper option, yet it would still likely cost you £2,000+.

By the way, you may be able to buy a new mechatronics unit outside of the dealership for around £1,000, but I used the dealership prices to get my point across.

If you are still convinced about buying a used Ford Focus Mk2 with a Powershift transmission, here are the typical symptoms of Powershift malfunction:

• car entering “limp home” mode or transmission warning messages displayed on the dashboard

• clunking or crunching noises when changing gears

• harsh gear changes

• a sensation that the clutch is slipping (engine revs rising too quickly and not matching the acceleration of the car)

• shuddering during acceleration (also a symptom of clutch slip)

• delayed take off from a standstill

• juddering / vibrations when taking off from a standstill

• car dropping out of gear while driving

Durashift CVT transmission failure

The Durashift CVT was developed as part of a joint venture between ZF and Ford. The internal designation for this transmission is CFT23.

It is a type of “Constant Velocity Transmission”, which uses cones and a drive chain to achieve stepless gear ratio changes. This makes for a very smooth transmission.

Have a look at the video below, which explains how CVT transmissions work.

Apart from their smoothness, another key benefit of CVT transmissions is that they can make the car accelerate while the engine RPM remains constant. This is an advantage because the engine can then operate at an RPM that is most efficient while the car is accelerating and when you floor it, the RPM climbs close to the redline and stays there to get the most power out of the engine.

So what’s the catch?

The catch is the same as with dual-clutch transmissions. I think that buying a used car with a CVT is not a good idea because they are difficult to diagnose and repair due to their uncommonness (is this a word?).

Traditional automatic transmissions with torque converters have been around for around 80 years (starting from GM’s Hydramatic). They are well understood and can usually be repaired locally (actually repaired, not replaced).

That’s often not the case with CVT transmissions. Although the principle of CVT operation is very simple in theory, only a few companies managed to create reliable and long-lasting CVT gearboxes, despite the fact that the concept of the CVT is even older than traditional automatic transmissions.

While the Durashift CVT is one of the few decent implementations of the CVT technology, it will still be expensive to fix when it fails because few garages have the knowledge and experience required to service them.

The bottom line is this: If the transmission fails, you will have a problem. 

Leave the CVT for mopeds and get a car with the 4-speed automatic transmission. It may still fail, but it is less likely to. Plus, it will be cheaper to fix if it does.

If you are still determined on getting a car with the Durashift CVT, look out for these symptoms of problems:

• jerky operation and rough take off (juddering)

• engine revs fluctuating when driving at a constant speed

• prolonged delay when taking off

• vibrations while driving

• any noises from the transmission

• a sensation that the gearbox is slipping

• poor operation when cold (test drive the car when the transmission is cold)

Focus ST – cracked cylinder liners

The 2.5-litre engine in the Focus ST has wet cylinder liners (also called an open deck design), which means that there is a cavity around the cylinders for the coolant to flow.  This is great for heat dissipation and makes for a slightly lighter engine. However, it does have a weakness.

Because of the thin walls, the liners are able to contract and expand as the engine warms up and cools down. The weakest points in the Focus ST cylinder liners are between the cylinders – that’s where the walls are the thinnest and those are also the hottest spots.

There have been cases of cylinder liners cracking in these spots. This has happened to both modified and stock cars, with the former being at a higher risk due to having more power (higher cylinder pressure and more heat).

The engine in the Focus ST is based on a 2.3-litre Volvo engine. Its capacity has been increased by boring out the cylinders.

Bigger bore = thinner cylinder liner walls = more susceptible to cracks

When a cylinder liner cracks, the symptoms are similar to a failed head gasket.

Here are the symptoms of a cracked cylinder liner in the Focus ST:

• intermittent misfire after a cold start

• white smoke (initially only after a cold start)

• dropping coolant level

• coolant system getting pressurized by the combustion gases

• no heat from the ventilation system

Only a small percentage of cars failed in such a catastrophic way (you’d need a new engine or a very expensive rebuild), so it may never happen to you. However, I advise against modifying the Focus ST for more power.

Some owners had the engine blocks in their cars strengthened by putting shims or inserts between the cylinder liners (kits are available). It is a fairly expensive mod as the cylinder head needs to be removed. Nevertheless, it is a solution if you are chasing power or having nightmares involving cracked cylinder liners.

This issue seems to affect only the Focus ST.

The Focus RS has a stronger cylinder block that is less likely to crack despite the added power.

There have been rumours that the post-facelift Focus ST uses the same block as the Focus RS. Sadly, I think they are nothing more than rumours. From what I’ve gathered, no one is safe and buying a used Focus ST means accepting a small risk of engine failure.

If you are going to buy a Focus ST, look out for the symptoms listed above, and do the radiator hose squeeze test – see part 4 of the used car buying guide for instructions. Also, avoid modified cars unless they had the cylinder liner shims installed.

By the way, these cracking cylinder liners remind of the cracking pistons in the Corsa VXR/OPC.

Focus ST – oil separator diaphragm failure

There have been cases of the oil separator diaphragm cracking in the pre-facelift Focus ST cars. It is a fairly common problem that also affects some Volvo cars.

The post-facelift Focus ST and Focus RS have updated diaphragms, which are less likely to fail.

It’s not terribly expensive to fix a ruptured oil separator diaphragm, but you should not drive the car with it because you may blow a camshaft oil seal, which would make it a more expensive affair.

The oil separator diaphragm is part of the positive crankcase ventilation system (PCV), and a failed diaphragm causes the boost pressure to get into the crankcase. That’s why the camshaft seal may fail if you continue driving the car.

If you really need to drive it, stay off boost.

You should not buy a second-hand Focus ST or RS with a ruptured diaphragm as you can’t know how long the previous owner has been driving like that.

A typical symptom of a cracked oil separator diaphragm in a Focus ST is a whistling noise when the car is idling. The noise will disappear when you pull the dipstick out or remove the oil fill cap.

Here’s what it sounds like:

The oil separator diaphragm is in the oil filter housing. Have a look on eBay – you may be able to find replacement diaphragms (cheap). If you can’t buy a new diaphragm, you will need to replace the entire oil filter housing (expensive), as Ford doesn’t sell diaphragms.

Tip: If your local Ford dealer gave you a ridiculous price for a new oil filter housing, you can get the same part from Volvo – their prices tend to be better.

Summary or problems & additional information

• The Duratec-HE (1.8L & 2.0L) engine was designed by Mazda. In Mazda cars, it is known as the L series engine. You’ll also find it in some Volvo cars. It is a reliable engine apart from a serious problem with the intake tumble flaps in pre-2003 cars. Fortunately, that has been fixed.

• The 1.6L Duratec is fine too (no major issues and no dual-mass flywheel).

• The Focus ST comes with a small risk of engine failure. There have been cases of cracked cylinder liners in these engines, and it’s more likely to happen in tuned cars. On a more positive note, the Focus RS has a stronger engine block and seems less susceptible to develop cylinder liner cracks despite the added power.

• The pre-facelift Focus ST has a weak oil separator diaphragm in the PCV system. It’s fairly common to see them rupture, but it isn’t a major problem as long as you fix it on time. When buying a used Ford Focus ST, make sure it doesn’t sound like a kettle in idle (a typical symptom of a failed oil diaphragm).

• Apart from the 1.8L and 2.0L Duratec-HE engines, which have timing chains, all the other engines in the Focus Mk2 have timing belts.

• If you’re looking to buy a used Ford Focus Mk2 with an automatic transmission, stay away from the Durashift CVT or the dual-clutch Powershift. They’re not something you want to own outside of warranty. Get a car with a traditional automatic transmission (available with the 1.6 & 2.0 petrol engines).

• The 4F27E automatic transmission mated to the 1.6 and 2.0 petrol engines is fairly reliable. The 4F27E is known for its soft shifting characteristic and has a better reputation than the CD4E used in the Mondeo Mk3. Remember to replace the transmission fluid on time and you shouldn’t have issues with this gearbox.

• The TDCi are decent engines with no major problems. The things that could go wrong are the same as for other modern diesel engines. By the way, they were developed as part of the PSA Group and Ford partnership. In French cars, these engines are known as the HDi. You’ll also find them in Mazda and Volvo cars.

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