Timing belt kits with water pumps

When replacing a timing belt that drives the water pump, it is common practice to replace the water pump at the same time – First Line supplies a range of Timing Belt Kits containing belts, tensioners, idlers and water pumps, under the company’s First Line and Borg & Beck brands.

The range consists of more than 40 references, covering over 3,000 applications, including many popular manufacturers such as Citroën, Fiat, Ford, Mazda, Mercedes, Nissan, Seat, Renault, Volvo, Toyota and Vauxhall. In addition to the timing belt, the kits contain all the necessary parts required when changing a synchronous drive system. They are supplied, as standard, with the water pump, pulleys, tensioners and fixing components, where applicable, meaning technicians receive everything they need from one source.

Technical layout drawings aid the identification process, available in its online catalogue webcat.firstline.co.uk, where the full range can be looked up via application or cross reference. The kits are backed by a comprehensive two-year/24,000-mile warranty against manufacturing defects, if replaced in line with the manufacturers schedule.

Wearing the black belt – by Rob Marshall

Like many other motor car components, the auxiliary drive has evolved considerably. With the assistance of renowned belt pioneer and manufacturer, Dayco, Rob Marshall looks at the implications and opportunities for the independent repairer.

While the earliest fan belts were manufactured from rope, followed by leather, it was found that increasing a belt’s running surface area to form a ‘V’ section reduced slippage and, therefore, enhanced reliability and longevity. Taking advantage of developments in polymer technology, rubber compounds replaced those early rudimentary materials relatively quickly.


As cars matured, the fan belt became responsible for transferring torque to an increasing number of components, although
its original role of driving the water pump (along with its power-sapping fixed fan on many earlier models) became

less prominent. The addition of more auxiliary mechanisms, from alternators to air conditioning compressors and more, demanded a rethink of the original belt design and the multi ribs, (known otherwise as Poly-V/Multi-V designs) provided
the advantages of being not only thinner and lighter but also able to provide a larger working surface area than that of the original V-belt. The added flexibility and thinner construction made the drive more energy efficient, resulting in cooler running and longer component life. Additionally, the different belts’ reverse sides could be used to drive either additional pulleys, or tensioners, as dictated by the requirements of the engine designer, many of whom prioritise keeping the auxiliary mechanisms as close to the engine block as possible.

Many early ribbed belts were produced from neoprene, a type of synthetic rubber but, unsurprisingly, technology has not stood still. Dayco, for example, makes all its auxiliary belts from Ethylene-Propylene-Diene-Monomer (EPDM), another rubber- based synthetic material, which provides additional strength, reliability, durability and quietness.


Things are not always that simple for modern cars, because so many components, even tyres in some cases, are becoming make and model specific. As Dayco works alongside the OEs, it possesses the technical expertise to advise the repairer on correct-specification replacements and fitting techniques. It is also worth noting that the company does not separate its aftermarket and OE manufacturing facilities, so a Dayco belt that you fit to a customer’s car would be technically identical to that fitted by a main dealer, where Dayco was the original factory supplier.

Advising Autotechnician, Glen Goldstone, the UK Aftermarket Division’s National Technical Manager, explains: 

“With the latest models, sourcing a new belt is not dependent solely on dimensions; the original part may possess a more advanced construction – such as its internal reinforcing cord being manufactured from a different type of polyester, even aramid fibres. This engineering choice depends on its application.”

Mr Goldstone also highlighted real-world cases in which he discovered that a new belt’s part number suffix has not been checked by a garage’s supplier, to make sure that the belt’s construction matches that of the original. Even though it might fit physically, the incorrect materials used in a technically- incompatible belt can result in the overstressed new part failing after only a few thousand miles. He commented also that some belt manufacturers offer more than one belt construction for the same vehicle, whereas Dayco insists on providing a sole belt that will be fully-compatible for that application.


The consequences of a part disintegrating can be catastrophic. Apart from causing a breakdown, the flailing belt risks instigating further damage directly, not only to the expensive auxiliary components. It has been known for the engine to be ruined, should the wayward part become tangled and trapped around the crankshaft pulley, which can stall the engine and damage the timing system. The issue is not helped by certain manufacturer service schedules paying either little, or zero, attention to auxiliary belt maintenance. Some of them are more helpful, however, and provide a replacement interval.

While traditional checks for cracks and missing sections were sufficient for the old-style neoprene belt, those made from EPDM display different wear characteristics that are harder to detect. More commonly, the pulleys’ metal grooves dig deeper into the ribs as mileage builds, causing the original ‘v’ formation to wear into a ‘u’ shape. This makes assessing belt condition extremely tricky at a cursory visual glance. Dayco recommends that technicians adopt a ‘Check and Change’ procedure.

So that a serviceable belt is not replaced unnecessarily, Dayco also recommends that auxiliary belts are inspected at the recommended service intervals, especially after a timing belt change. To assist technicians, Dayco provides freely a ‘tread- depth’ type plastic tool, the ‘a-WEAR-ness gauge’, one side of which displays any side clearance evident between the ribs, the other measures how much material has worn from the ‘v’ groove. Finally, the technician checks the ribs for cracks through the tool’s 25mm square ‘window’. Should four, or more, flaws be visible, the belt must be replaced, because it is worn significantly.

Auxiliary belts are not made from one single material. Pictured is a MINI water pump friction wheel, driven by the belt’s reverse side. This dictates a special coating is used on that running surface.



Any competent technician will be aware of how incorrect tension and pulley misalignment will decimate belt life, making it essential to view belts not in isolation but in terms of a system. Therefore, the presence and condition of any tensioners, idlers and alternator one-way clutches should be considered.

In certain cases, just like timing belts, replacement auxiliary belts may be offered as a kit but enquire with your supplier if any other components require replacing, which are supplied separately. Naturally, always insist on OE quality.

Some types are of the elastic, or stretch, variety that requires no external tensioning medium. However, Dayco insists that these designs should be fitted with a suitable special tool, so the belt is not damaged before the engine has even been started. Consider also that, once removed, this type of belt should never be refitted. Where an automatic tensioner is not used on a non-elastic drive, a suitable auxiliary belt tensioning instrument should be an essential toolbox item.

Auxiliary belts have changed considerably, in terms of materials and design, from the old V ‘fan’ belts, which tended to drive solely the water pump and alternator.

As the UK car parc stands at approximately 32 million, over half of which are aged over six years, and presuming an average mileage of 12,000, many vehicles that aftermarket technicians encounter will require an auxiliary system inspection, at the very least. Therefore, the considerable market opportunities in relation to auxiliary belt systems should not be overlooked, not only for your business but also for customer safety and peace of mind. 

Checking for wear in modern EPDM belts extends to more than checking for perishing and cracks. The depth of the ribs also need assessing.



6 = number of ribs
PK = belt section (automotive class) 1270 = external length (mm)



  • ‘S’ belts: higher performance compound used. For example, 6PK1836S Fiat 1.9 JTD and 5PK1745S Mercedes Benz A & B Class diesel.
  • ‘EE’ belts: elastic (stretch) belts. You should see an ‘ELABELT’ logo, example 6PK1059EE Ford Focus 1.6 petrol.
  • ‘K’ belts: internal cord reinforced with aramid fibres, example 5PK1121K Volvo 2.0 & 2.4 D.
  • ‘DT’ belts: fabric material used on the rear belt surface; 6PK1080DT for PSA’s 2.0 HDi Hybrid (Peugeot 508 RXH)
  • ‘PM’ belts: white fabric on ribs, 6PK1041PM and 6PK848EEPM, both for PSA 1.2 3-cylinders range.


Tackle timing belt changes

You may love them or hate them, but timing belt changes are not getting any easier. We can probably all admit to having got it wrong at least once and being presented with the obligatory blown up latex glove labelled ‘bag of compression’. Here are some hints and tips from INA, the largest belt component supplier in Europe, useful to avoid costly mistakes.


The engine should be at room temperature when setting the belt tension. When the engine gets hotter it expands, so setting the belt tension of a cold belt on a hot engine will mean it is loose when it is cold and not as tight as the vehicle manufacturer’s process specifies when hot. A cold engine is what we call in the trade a datum, a constant that we should all stick to. It sounds easy, but getting the engine at room temperature before you set the belt tension can be tricky, especially if it’s a quick job and the customer has driven 10 miles to get to you. So, make sure you get a tea break or lunchtime in the process or better still, get it on the ramp the night before.
Always change all the pulleys and tensioners. INA tensioner sets and kits are original equipment components and include all the bits you need to change the timing belt. You have to remove most of the Front End Auxiliary Drive (FEAD) components to do the job, plus they have done the same mileage as the timing belt and can do as much damage as the belt if they fail, so why not change them at the same time?
Some garages believe that vehicle manufacturers dream up a complicated process to deter independent garages from doing the work. It is certainly working but they don’t do it for that reason. VMs will start from the position, “I need X tension to make sure the belt doesn’t fall off until the scheduled belt  change,” they will then develop a process that gets them there as quickly and as accurately as possible, repeatedly. Remember, they must do the same as you on a moving production line and are doing it hundreds of times a day. Admittedly, you have a car hiding all the bits you need to get to, but think of it like this, if it will be OK if you miss a few bits out of the process don’t you think the VM would have done it like that?
This time, thinking about if it actually tells you how to replace all the pulleys and tensioner. Rover KV6 is a good example for this – if you follow the OE instructions with a new tensioner, it comes loose and you bend valves. Another good example is the Vauxhall Corsa 1.7 CDTi, where it says retract the tensioner from the belt and lock it and after fitting the new belt just let it go, but if you have the new tensioner in your hand, which way do you turn it? If you have not got enough information call our technical hotline.
For the same reasons in Step 2, VMs will develop an accurate timing process and tools that produce repeatable engine or fuel pump timing in a production environment, to give maximum performance and minimum emissions every single time. If that involves some expensive special tools then that is what is required and a bottle of Tippex just won’t give the same results!
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Timing belts and tensioners that use friction washers to damp out vibrations don’t like oil or water, leaving a leaking oil seal or a leaking water pump is not doing your customer any favours as you are risking total engine failure. A £2 seal and a few minutes work would be doing your customer a favour.
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STEP 6: FIP pulley banana slots
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One of the most common mistakes, usually due to lack of timing pins or tools, is to not lock the cams and loosen the cam pulleys, instead using the ‘universal timing tool’ Tippex to guess the valve timing. Unfortunately, when it comes to tensioning the belt, not having loose pulleys means you will have a loose side of the belt and a tight side of the belt. The tensioner is usually on the slack side so setting the belt tension in this condition will result in an over-tensioned belt.
With the camshafts locked and the pulleys loose you have an even tension all around the belt, which is how the VM intended you to tension the belt. The same can apply to fuel injection pumps – when pinned, the pulleys can be slackened on banana slots allowing some free movement of the belt.
Relates to Step 3, but some tensioners are not marked and weirdly, you turn it one way and the pointer goes in the opposite direction, just to confuse you. Read the instructions carefully and if you are not sure, or it’s not clear, ask.
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Torque wrenches and torque values are vital pieces of kit when it comes to replacing timing and auxiliary belts and their associated tensioners and guide pulleys etc. With belt loads increasing and space reducing, some of these components are expected to perform harder than ever before. Not using a torque wrench can prove fatal to an engine if the bolt breaks.
Always turn the engine over by hand after the process to make sure it turns OK. If possible, it’s also a good idea to leave the belt cover off so you can see whether the belt sits nicely on the pulleys when running before rebuilding it fully.
REPEXPERT Technical Hotline: 01432 264 264