imok

And ur right the light comes on when u start driving it.... If u turn it off and back again and let it idle it doesn't come on.... As soon u start driving it ( higher rpms) it comes on and stays flashing

jseklund

My guess, from what you describe is that it's your oil pressure warning light...a known issue with the 1.8T engines. Based on the fact that it came with a knocking noise - I'd suggest that it probably is NOT the sensor.

Possible causes are failed sensor, failed oil pump, clogged pickup screen in the oil pan.

Most likely a clogged screen - which means you need to drop the pan to clean it and check out the level of damage. You should probably also pull your valve covers and look inside your heads for damage if this is the case. This can be a serious problem for your engine.

Better oil, more frequent oil changes, and a larger oil filter all help alleviate this problem, once you have cleaned the screen.

Unless you can confirm it's something else, I wouldn't drive it too much until you fix the problem. No oil to the heads will create some serious damage.

GTA_Driver

Do you feel a loss of power at higher RPMs? It could be a failed pump, not actuating your variable valve timing.

Bottom line, you will need a competent mechanic to take a look at it. Among the dozens of guesses here, one may be correct. Which one?

I will emphasize, take it to a "competent" Audi mechanic, whether the dealer, or an indy shop that specializes in Audis.

imok

Thanks guys I'm going to replace the pump... That's what thought too....after all clean will put new oil with some Lukas oil stabilizer .... If this doesn't resolve it.... I will take it to a more knowlegble mechanic

jseklund

It's unlikely the pump to be honest. They don't fail often - as I said, it's most likely a clogged pickup screen.

You need to drop the pan to clean the screen. If you want to replace the pump, you can - but it's most likely unnecessary.

Clean the screen and then pull the valve covers to assess the top end damage that has occured...if you've been driving it with a flashing oil pressure light, you probably have at least some damage in there....hopefully not enough to be of concern.

This isn't really a guess - it's pretty much a known issue with the car. It could also be a failed sensor, but since you're getting other symptoms (noise), it sounds like an actual issue. A failed sensor will throw the light on the dash and beep, but not cause any engine noise...

The A student would get a pressure guage and double check the sensor port....

Prospeeder

dude its not the oil pump. Just pull the pan, you will see the pickup tube completely blocked. spend some time soaking, flushing, and scraping it out. I have yet to replace a pump in the dozens and dozens of 1.8T cars with this problem. Make sure to check bearings and pull a valve cover and pull bearing caps and check that the engines worth saving. STOP DRIVING IT