I have a 2006 Audi A4 with about 90,000 miles on it. Recently, the engine has been making a clicking noise when it is warming up. Once the engine is warm it stops. No, performance problems, just the sound. It got an oil change recently (I always use synthetic oil), but the sound was occuring before and after the oil change. Any thoughts on what it could be?
Is this an A4 or an A6? You’re post says A4, but the tag says A6. And, what engine is in it?
An Audi forum can probably help better, as this sounds a bit more specialized. I first thought about valve adjustments, but some forums suggest the valves are hydraulic, no adjustments. Others point to possible timing belt tensioner noise. Does your engine have a chain or a belt? A belt may be close to needing changed anyhow.
There’s a dozen possibilities. I’m assuming you keep the car well maintained. If not, there’s two dozen. One thing you could do to narrow it down is find a 3 foot piece of garden hose, and use it as a stethoscope. Be very careful, as there are fan blades and pulleys and all sorts of things you can get hurt when the engine is running. But if you are careful, you should be able to determine the location where the sound is coming from by moving the end of the hose around the engine compartment while you listen on the other end.
My first guess is you need a pulley belt re-tensioned, or maybe a new belt. That’s a simple fix. Next would be something on the belt drive chain: the water pump, alternator, air-conditioner, or an idler pulley. More expensive, but not that bad. Next would be the timing belt, or the valves may need adjustment. Talking more money there.
When I was growing up, my parents had a 1949 Dodge and the exhaust manifold gasket started leaking. The escaping exhaust made what sounded like a clicking noise.
This may be your problem. As the car warms up, the exhaust parts expand and the leak is sealed.
I’m wondering something really simple - which is, have you checked the oil?