KiwiS6

John Kintz

2008 s6 constantly running out of coolant (happens all at once) . Water pump replaced. Showing fuel pressure regulator sensor 2 error. Just purchased. Will also carbon clean while I have manifold off. Any other advice? Maybe new thermostat ?

haloguy628

Had the same problem. It turned out to be one of the high pressure fuel pumps that sit on tops of the valve covers in engine bay. Audi advises to replace both if one goes bad. I got the pumps from Audi Naples which had the best price. I got both for $779.62.

John Kintz

You are amazing! I can not thank you enough for this. I already purchased the lower fuel pressure regulator for $27 part #p2293. I don't see how that equates to your total for oarts. Again I can't thank you enough.

haloguy628

John your coolant loss maybe due to micro cracks in the coolant overflow tank. The V10 is stuffed in small space and so the underhood temps run quite high. That causes small cracks developing on the overflow tank. It only leaks when you shut off hot engine so the coolant stops circulating and the hot block heats the coolant which starts to expand and flows back to the overflow tank. New overflow tank is around $70 - $80. The part # is 4F0121403AA. Another cause of your coolant leak may be the O ring on the overflow tank lid. If it's weakened by age then it will leak after you shut hot engine again due to the increasing pressure in the tank as the coolant expands in the block. That part # is 1H0121687A and it's around $3.

What is part# p2293? Do you have VAG part #. The fuel pump with the FPR on the BXA 10 cylinder is part# 07L127026A. You can't buy the solenoid separately. There are two pumps. One for each bank.

engine | Audi Audi A6/S6 quattro 2007, fuel pump fuel rail injection valve 5.2ltr. 10-cylinder+ BXA

Oh wait a minute. Did you mean the p2293 to be the fuel filter as that one has the FPR built in. If that causes your problem then you are lucky. I too first replaced the filter but that did not solve my problem. In the end it was one of the high pressure pumps in the engine bay. It's the #1 in the above ETKA diagram. The pump cost around $400 each and you have to replace both.

John Kintz

Ok haloguy, dropped car off at audi today to see what they can confirm. Where is the friggin fuel filter!?? You are correct BTW. When I saw the code p2293 pop up I did think fuel filter. I just can't find where the damn thing is located!!!

haloguy628

The fuel filter is below the right rear passenger door. You need to jack the car up and take off small plastic cover on the bottom in front right rear wheel and you'll see it. The hoses have push clips that are kind of PITA to remove. Use wise grips but be careful as the push rings are plastic. Remember which hose goes where. The filter also has the FPR built in so get the right filter. It should take no more than 15 minutes to change it.

Mahle Fuel Filter with FPR for S6

Location of Fuel Filter

John Kintz

Thank you! You were totally right!!! They said it's the lower fuel pump!!! Quoted me $1200 to fix not including the $180 dianostdia.
They also said there was an issue with the secondary temp sensor or something that had to do with catalytic converter.

raj99

John,

Try searching here, with your appropriate car details, and it usually gives a blow-out picture of the part and it's location in the car: https://genuineaudiparts.com/

Also this site is pretty great: https://audi.7zap.com/en/rdw/

John Kintz

This is what I will be ordering to replace the low pressure fuel pump I understand I will have to take out back seat. I already have the fuel filter. I'm pretty sure this will do it.