Diagnosis first.
Repair second.

First things first: identifying the problem

A very odd rattle appeared when starting the car with a warm engine. Given the low mileage of around 50,000 km, the underside looked practically new and worn components were hard to expect. The sound lasted only about a second and then faded, which made tracing its source difficult. It was also telling that the problem never appeared with a cold engine.

For one of the attempts we removed the clutch pedal position sensor so the engine could be started without pressing the clutch. Normally the Astra has a safeguard that prevents starting with the clutch released. This clearly made things worse. Such behaviour is typical of a damaged dual-mass flywheel, and that is where we looked next.

This time the wisdom of the internet helped: with a lead in hand and the right search terms, we found several articles about faulty dual-mass flywheels fitted to some Opel models with 1.4 Turbo engines. A good workshop is not ashamed to admit that it looks things up rather than guessing.

The repair itself went quickly

There was no other way than removing the gearbox and taking a look. With the gearbox out we had access to the clutch and the flywheel. As expected, almost everything looked as good as new, only the thrust bearing was noisy. The dual-mass flywheel itself had clear play, though not as much as we usually see. Here too the symptoms were not quite the usual ones, which fitted the theory of a factory defect.

The clutch and pressure plate looked very good. Still, given the condition of the thrust bearing and the need to replace the flywheel, we agreed with the customer to replace the complete clutch. Leaving used parts between two new ones did not inspire confidence. In our view this should be standard practice in every workshop, but believe it or not, it is not always the case.

The job was a success. The new flywheel makes no noise, neither with a cold nor with a warm engine. It is a pity the car was already out of warranty, because in our opinion this was a factory defect and Opel should have put it right.

First look at the leak

With the car on the lift there were no visible leaks in the hoses or the radiator, and those are the parts heavy leaks usually come from. Only after refilling the system did it turn out that coolant was escaping from behind the timing belt cover. That was unusual, because the only part there that can cause leaks is the water pump. Pump leaks are normally small and slow, and here we had a waterfall.

Removing the pump revealed the cause. Despite the age of the car and a mileage of around 170,000 km, the pump was still the original one. If a car has had several owners, the odometer reading cannot be fully trusted and the real figure may be considerably higher. Either the timing belt had never been replaced, or someone replaced it and left the factory pump in place.

The shaft in the pump had shifted in its bearings. The pulley the timing belt runs on started rubbing against the pump housing and wore a sizeable hole in it. That is where the coolant was escaping so quickly. The puzzling job turned into a routine one: a new Contitech timing kit, meaning belt, tensioner, rollers and of course the water pump, went under the bonnet. Plus fresh coolant and an alternator belt. The engine runs quieter, the squeals and hissing are gone.

What does the water pump have to do with the timing belt?

Replacing the water pump with every timing belt service is far safer than replacing the belt alone. Bearings and seals wear and age too. A failure of the water pump, the tensioner or the guide rollers can damage or snap the belt. The end result of such a failure is disastrous for the engine and causes enormous damage.

While it was still being driven into the bay we noticed the brakes behaving very strangely. As a workshop that takes its work seriously, we could not let that pass. With the wheels off it turned out that the discs and pads were in a dreadful state and needed replacing immediately. Besides the brakes, the front control arm bushings were heavily worn as well.

And it was supposed to be a simple tyre change

The car came from the American market, so the choice of parts was not as wide as for European models. Despite that we managed to source discs and pads from the respected TRW brand. While replacing them we also changed the brake fluid for fresh one and adjusted the parking brake.

After the control arm bushings were replaced, the suspension geometry was set. On the new tyres the car became stable and confident to drive.

As usual: a timing belt replacement

The customer reported trouble starting the engine in low temperatures and oil leaks, and suspected faulty glow plugs. After checking the car, the customer's hunch proved right: the glow plugs were burnt out. The oil leaks came from around the oil filter and the valve cover. Engine diagnostics also revealed a faulty EGR valve.

Unfortunately the engine layout is not very mechanic-friendly. Poor access to the glow plugs usually means cars are driven for a very long time without replacing them. By the time the engine stops firing properly, the plugs are very old and often still the original ones. Getting them out then becomes a serious problem.

It was the same here: two plugs came out, the next two only partly. We managed one ourselves, for the last one a specialist had to be called in. Luckily we work with a company that handles exactly this. For them it was no great trouble, the remains of the broken plug came out and made room for a new one. We could get back to the rest of the work. The exhaust gas cooler that had been blocking access to the plugs went back in place, and the EGR valve was cleaned.

And that was not the end of it

The oil filter housing and the oil-to-water cooler were removed. New gaskets will keep oil leaks away from that area for years to come. Replacing the valve cover gasket requires removing the injectors, so the copper washers underneath, which looked poor, were replaced with new ones and the injector seats were machined.

Finally a new timing kit went under the bonnet. The old one had covered around 50,000 km, but it had been fitted more than seven years earlier. The age of a belt greatly affects its life. Driving on an old belt must never be allowed, even if its mileage is negligible. Should it fail, the damage inside the engine will be severe.

EcoBoost engines appeared in Ford's line-up around 2010. More and more of the cars fitted with them are on our roads, so they come to our workshop regularly. This time it was a Mondeo with the 1.6 engine.

The car had just changed hands and, since its full history was unknown, the customer asked for an inspection, a change of all filters and a new timing kit together with the water pump.

A timing kit from the German company HEPU went under the bonnet. The kit included the water pump and rollers as well as a belt from the well-known Contitech brand. Everything was fitted using the dedicated locking tools.

Trouble with the suspension

The car hit a kerb with its rear left wheel on ice. Nothing serious was damaged, but after a few days the bearing in that wheel started making noise. We normally try to replace a bearing without dismantling the whole suspension, but in this case it turned out that several other parts needed replacing as well.

What a thorough suspension service looks like

First we noticed a cracked suspension spring, then it turned out the swivel bushings had play and were knocking, while the lower and front rubber-to-metal bushings were badly perished.

Choosing the springs proved tricky. The car sat noticeably lower than others we had seen before, which suggested the previous owner had fitted lowered suspension. There was a risk of getting the spring height wrong and leaving the car sitting unevenly. After a short talk with the customer we decided that instead of buying two rear springs and risking a difference between front and rear, we would buy a set of four. The choice fell on the popular and well-regarded Eibach Pro Kit. It proved right: the car kept its stance and the quality springs work beautifully.

Finally a few smaller jobs, such as an oil change in the rear differential and adjusting the handbrake. With the bearings, springs and bushings replaced, the alignment was set. The car now drives quietly, straight and confidently. Which is how it should be after a visit to a workshop.

What routine servicing looks like

For its age the car has a modest mileage, a little over 54,000 km. At that sort of mileage it is very often the easily forgotten items that need attention: brake fluid and spark plugs.

Because of their age, such cars go to authorised dealers less and less often. In other workshops the scope of work is frequently set by the customer, and certain small things slip through. It was the same here: the spark plugs were long past their best and the ground electrodes were heavily worn. That causes slight engine vibration at idle, a drop in performance and higher fuel consumption. They are worth replacing regularly, because forgotten entirely they can play a very nasty trick and lead to serious engine damage.

Besides the standard oil service, new air, cabin and fuel filters were fitted. The last one matters a great deal in this car, because it has the fuel pressure regulator built into it. If it fails to work properly, especially on a TFSI engine, it can cause major running problems.

The final item needing attention was the heavily worn front brake discs and pads. Although the discs looked evenly worn to the eye, their thickness was almost a millimetre below the permitted limit. Precision matters enormously when replacing brakes. Poorly cleaned hubs mean the new disc will not sit flat against them. The result is brake judder, uneven pad wear and even warped discs. Finally the Audi got fresh brake fluid, as there was no record of when it had last been changed.

A classic: a stretched timing chain

The characteristic rattle from under the bonnet pointed to a worn timing chain. Curiously, the customer had had the timing replaced in this car less than a year earlier. That says little good about the previous mechanic. There was no other way than removing the chain cover to check its condition.

But not without surprises

Practically from the start the job looked odd: too little time since the previous replacement, and several other details the customer mentioned did not add up. The car should have been running like new. Once we began and set the crankshaft to its starting position, with the first piston at top dead centre, it turned out the camshaft locking tool did not fit. That suggested we would find a damaged guide or tensioner, and that the customer was very lucky the valves had not met the pistons. The truth, however, was different.

Having stripped everything down we found the cause. During the previous timing replacement someone had failed to seat the key of the crankshaft gear in the slot on the shaft, and did so twice.

After fitting a new timing kit together with the variable valve timing gear, this time a genuine part rather than an aftermarket one, the engine began running quietly and the camshaft sensor faults disappeared.

Remember: when choosing a workshop, do not go by price alone. Ask around in as many places as you can.