I have a 2004 B6 S4 that seems to possibly have a small oil leak that is causing noxious smells to enter the cabin. I mostly notice this when waiting at a stop light, not so much when underway. The smell is definitely motor oil, not manual transmission fluid, steering fluid, or coolant. If I pop the hood, there is a faint smell of burning oil but I can't tell from where. I crawled under the car and there is no evidence of oil leaks (or leaks of any kind). I tried looking around the heads/back of the motor, but that compact V8 doesn't allow much clearance in the engine bay for inspection. The oil level is at the max and the car doesn't seem to be burning oil otherwise.
Anybody know if:
- The S4 has a PCV valve that could have gone bad?
- There are any oil lines that I should inspect more carefully somewhere?
- If the valve cover gasket/other gaskets are known to leak on these cars?
- There is a air cabin filter that should be trapping this odor?
The car is about to go out of warranty in June and I want to make sure I get the issue fixed before this happens.
if the car is truly burning oil you should notice a drop in actual oil level, even a small loss would be noticeable after a time. Also I assume you've looked inside of all the plastic panels that are on the bottom of the car, sometimes leaks land on these panels and don't get noticed because they don't land on the ground.
I too am noticing a drop in the oil levels and smell burning oil when I am idle at stop lights, and this is more notable as I am nearing my 55,000 mile oil change. I opt to change my oil every 5,000 as opposed to 10,000 miles. I had to add a whole quart just to get it back into the safe zone. I rule out PVC or hot plastic smell since I am confident on the difference in between hot PVC and burning oil.
As this car is certified I am taking it into my dealer to see if they address this issue or claim that nothing is wrong. I have read of oil leaks on other S4's so I know this is a legitimate issue on some of them. One service adviser on the phone at the dealer told me oil burning is normal, I right immediately disagreed with her since no recent model S4 should be chewing though a whole quart in under 5,000 miles.
This car had some work done previously for coolant leakage, I am just wondering if they might have disturbed some gaskets that are in place to prevent oil from leaking?
I noticed the hot oil smell in my 2004 S4 Avant starting a few weeks ago, accompanied by a miniscule increase in oil loss. No visible dripping. The car is currently in the shop where they've found a leaking valve cover. As the car was due for an (early) 35k maintenance anyway, I took it in but didn't specifically mention the oil problem, just to see what they turned up on their own initiative. So I'm pretty confident their finding is authentic (and also that the 35k inspection, at least in this case, involved actual inspection, which is good).
Sounds like this might be shaping up to be a common issue? And not a cheap fix, I might add. (Especially as the dealership is the only place I've been able to find around here who seem to know one end of an S4 from the other.)
I'd be curious to hear if this is age- or mileage-related. At 24,500 my car is very low mileage for its age. Are other people running into the oil problem at similar mileage, or just at the same time?
As I write this my dealer is replacing BOTH valve cover gaskets under warranty. I did have to convince them this was a problem beyond Audi specifications which they kept telling me on the phone. I would take their oil burning spec's under caution as some engines will burn oil, while others will leak in a manner similar to mine.
It's good practice to keep a careful eye on your engines oil burning patterns. I noticed mine only because it has never lost so much oil so fast until now. If your dealer gives you a quick reply over the phone about Audi spec's, try and convince them to take 20 min and have a look anyways. If they don't agree then try another dealer for a second opinion.
My 2004 S4 goes through about a quart and a half (sometimes closer to 2 quarts) of oil between changes (every 5K miles). Haven't been able to figure out where its going yet... I've heard Audi considers a up to a quart loss as "normal" for this engine (4.2L V8). I DO have a persistent smell that I often get from the engine area, but to me it smells more like burned rubber, but I'm not sure I know the difference between burning oil and burning rubber....
The dealer will always say your engine will burn a specified amount of synthetic between changes, however, they do not specify a general "rate" at which the oil is burned.
If you are as anal about your S4 as I was with mine you will notice the burn rate has changed significantly enough to point to a leak somewhere. Given the tight fit of the 4.2L into the B6, I recommend you lean on the service rep to put it on a lift and have a technician check the valve cover gaskets. A leak such as that is very clear if they take the time to look as opposed to sitting behind their kiosk making predictions. Audi maintenance rep's should know better by now since they have 5 years of knowledge on this engine/B6 combination in terms all the mechanical items that might arise.
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