Audi A4 Cabriolet 1.8T
PART TWO: The 1.8T cambelt doesn’t look especially easy to change – the front bumper has to come off! Andrew Everett gets his hands dirty and changes the belt, the water pump and air-conditioning compressor.
Part two: First job on our auction-purchased A4 is to fit a new cambelt and water pump.
The Audi A4 followed the traditional Audi design in having front-wheel drive, but having a North-south (inline) engine
– a design that goes way back to the late-1960s Audi Super 90 as well as the five-pot stuff. That means the front of the engine is a tight fit against the radiator with nowhere near enough room to swing a spanner. So, the front bumper has to come off and the complete front panel drawn forwards to give the required six inches or so of room to access everything.
There are various ways of doing this – the official line is to replace one of the bumper mounting strut bolts per side with some studding and a nut, the idea being that you slide the front panel (also called a lock-holder because it houses the bonnet catch) forwards.
We did things slightly differently for a couple of reasons. Our air-conditioning system had absolutely zero gas left, so I disconnected the offside aircon pipe going into the side of the condenser – this would hopefully give more room because the front panel may move forward even more. I also removed the headlights – it’s easy with just two Torx bolts to remove and one to slacken per side before the lights can be wiggled out. I removed them as they were cloudy and needed a clean-up anyway. This also made accessing the bumper retaining nuts easier. I didn’t bother with the long bolts either, preferring to rest the front panel on a couple of sturdy plastic buckets – it’s not that heavy.
Despite what the Haynes manual says, there were not the expected three nuts or bolts holding the front bumper on at the extremities – but with the front headlight unit removed, it was very easy to remove the one 10mm nut per side fitted to our Cabriolet – we suspect the saloons and Avants with their identical front ends differ slightly here from the convertible.
Improved part
The original 1.8T cambelt tensioner was of the gas strut type. This uses a tensioner with a gas pressure plunger just like a bonnet or tailgate strut and they are known to fail, losing pressure and causing the belt to jump.
The Ina-made belt kit GSF supplied us was a later supersession with a mechanical adjuster very much like the type used by GM engines (Vectra, Astra) as well as older single-cam VAG units. This is a straight swap and easy to tension with an 8mm Allen key. The part number for the belt kit is 129VG1100; and GSF confirmed that INA (original equipment from the Schaeffler LUK Group) made a component change from kit 5636471 (gas tensioner) to 530054610 (mechanical). The original type is no
longer manufactured and while the £264 list price is expensive, GSF’S discount reduces this considerably.
We were worried about the belt on ours, but despite the lack of an invoice for a belt change, it had received a new one possibly between 10 or 20,000 miles ago and was still fit for work.
Finally, we found the source of the rattle at idle – the Denso-made aircon compressor was indeed faulty with lots of play in the end bearing. I fitted a good secondhand one, had the system gassed up and it seems fine.
As ever, the rules of cambelt changes apply – check, check and check again. Use a torque wrench and follow instructions to the letter. INA belt kits come with diagrams and torque figures. Wash away antifreeze spills with water, and clean-the ground with detergents – antifreeze is poisonous to wildlife.