actually heavy weights are designed for motorsport use.

 

Right, because of the extreme conditions of racing. Not for everyday use. If you trailer your car to the track and that's the only place you run it, at high rpm for extended periods, then use whatever you want. But for everyday use, stick with what's recommended.

If there was any reason in the world that heavier oils would preserve engine life, reduce failures (and associate warranty repairs), don't you think the manufacturer would recommend it? I know Saab does recomment 10W-40 synthetic for its engines (actually it says, "SAE 10W30 or 10W40 . In markets where these viscosities are unobtainable 15W40 may be used instead, although not in winter. Use 5W30 or 5W40 oil in climates with temperatures regularly below -20°C (-4°F) . In climates with a constant temperature of +15°C or above, use 15W50 or 20W50 oil of synthetic or synthetic-based type."). But we drive Audis, not Saabs.

Quit trying to out-think the engineers. Everything that may work on the race track does not guarantee that it's a good fit for the street.

 

Product placement is done all the time in all sorts of industries and can range from straight pay to play, to providing better pricing to the factoryon parts, to providing engineering and design support, underwriting of testing, etc. Audi would likely not reccomend a product that did not meet minimum spec as then quality issues would become apparent, butmight not neccisarliy reccomend every product that does where they do not have an incentive to do so. Although that is a pretty long list you posted. My bro-in-law has a business that helps people do exactly that and the auto industry is his biggest business segment next to food products (think the peanuts you get on planes, the stuff in hotel minibars, etc). Vendors see it as buying advertising and manufacturers, airlines, hotels, etc see it as a way to gain leverage on pricing.

 

People can use whatever they want...gear lube if they want. It's their car. I was just answering the question and backing up my answer with documentation.

I can also speak from personal experience. When I once tried 15W-50 I got crazy valve slap when starting because the oil was too thick to rapidly pressurize the hydraulic lifters. I immediately changed it out. Was that damaging? Probably not significantly, but over time I think it would have worn things out faster. It just couldn't be helpful.

 

i just did a compression check and it was 185 psi or so on all 4 cylinders. the pcv valve was ok, the mechanic told me that everything was ok. He also recommended me to use the 10w60 castrol from germany ($25 a quart! ). what do you guys think?

 

You can try 10w60 (not that castrol) and see if that helps. Think a 50w will be better to try first. Just remember that the thinner the oil, the better mpg you can get

 

I just re-read your first post (and not all the others). Did this happen one time or do you consume a lot of oil all the time? I had my oil light go on once and once only and needed to add a quart. The car had probably around 35k miles on it. I had checked the oil prior to that and it was fine. I now check the oil regularly and have never had that happen again. The dealer had no explanation (it's a CPO car). I continue to use 5w-40 or 0w-40 oils.

For $25 per quart (4x as much as the best major brand synthetic), I'd keep a couple quarts of Castrol 5w-40 or Mobil 1 0w-40 in the car and just check your oil at every fill up. $25/quart is just nuts.

BTW, whose your mechanic and does he want to sell you the oil?

 

he is not forcing me to buy the oil, he was just suggesting me to use it. he told me that it'll last for 9000 miles before oil change and it is usually used on bmw cars such as m3 and so. he also has pentosyin, liquimoly and motul.

 

Was this a one-time thing or does it happen all the time?