Hello. I have a 2004 A6 3.0 Quattro. The timing belt broke and of course bent some valves on passenger side head. Pulled both heads and had them reconditioned. Put everything back together including water pump, thermostat, tensioner, etc. Car started on a dime and ran perfectly for 30 minutes and 20 miles. Low oil light came on with engine noise so shut the vehicle down immediately. Oil level was good. Pulled the oil pan and discovered LOTS of sludge. No metal in pan. The pick up tube and the screen on the pump had sludged up. Pulled the valve covers and discovered that 2 exhaust valves on the same cylinder are bent. Now the head needs to come off again. Timing looks to be good as we marked up the alignment. I am clueless as to what happened. Could a couple minutes of low oil cause exhaust valves to bend??? The car has been sitting since September. I need help...

 

Is there anyone that can offer some advice or thoughts?

 

Low oil should not cause valves to bend. Usually when our cars throw the low oil light (yellow light) there is still around 4-5 quarts of the 6-7QT capacity.

 

What do you mean you marked up alignment?

Did you use the c-clamps on the cams
were the cams set with the crank perfectly aligned
did you use the AUDI type tools to do the job.

If not you timed it wrong. You can not do a tb on a 3.0 without those tools.
especially if the heads were off time with the crank due to the broken tb.

You can buy new valves cheap at advance auto or online and replace them yourself.

Run some sea foam through the engine as recommended to clean out the sluge when you get the new heads broken in.

 

We rented the C-Clamp cam alignment tool from Blauparts and everything lined up perfectly. Again, the car started on a dime and ran for 20 miles perfectly...then the oil light came on...then the noise. I just can't figure out how the valves could bend without the timing getting messed up. The car still starts on a dime. Doesn't make sense to me.

Another question...since the heads were just redone, do I need to get it machined again this time? or can I just replace the valves and slap it back together? Same gasket set? New head bolts? Ugh!!!

 

The only way I know for low oil pressure to bend valves is for the hydraulic belt tensioner to back off and let the belt slip a few teeth. Although there are spring tensioners too, under certain condtions, the hydraulic tenioner failing to hold tension might let the belt skip. Other than that, it would be unlikely for the cam timing to be right and the valves hit the pistons unless the engine was overrevved.

 

UPDATE!!!!!
I am really looking for some theories now. I got the car tore down and put the Audi cam tool on both heads. Passenger side intake and exhaust cams were perfect. Drivers side exhaust cam was 180 degrees off! We are clueless as to how this could have happened. Timing belt was in great shape. Belt tensioner was still tight. All 4 cams were well lubricated...oil came out of the cam caps when we removed them. None of the lobes on the exhaust cam look like they got hot. Everything looks perfect, with the exception of the sludge in the oil pan and pick up tube. I really need some help with this as I can't imagine putting this all back together and having the same problem again. Please help!!!

 

Can anyone help me with this puzzle? I'm ready to put the head back on but want to make sure that I know what caused the exhaust cam to spin 180 degrees with no broken timing belt. Please help!!

 

Can anyone offer any insight???

 

I would take a very close look at the inside of the belt. If it were slipping you should see some scuffing on the shoulders indicating that. Otherwise however improbable it seems to you it is entirely possible the exhaust cam was installed incorrectly.