chicago maroon

It went into the shop with heat. When I got it back, no heat. repeated bleeding has done no good. My local shop says heat gets up to some control valve they say is a $1000 part and want to replace that and see if it fixes the issue. I don't like the idea of spnding $1500 to see if it fixes the problem Ideas?

chicago maroon

This is the actual part number for the heater valve, but now I see I have bigger problems. Even though the oil cooler was replaced in March 2011, I see I have lots of oil in my coolant. It's now brown instead of red. I think it's time to part this car out or sell it to an Audi mechanic.

silverd2

If the wrong type coolant (anything but G-12) was added to the G-12 (ONLY acceptable coolant), it turns nasty brown and will begin to solidify and clog things up...maybe including the heater cores or valves(?).

If coolant doesn't seem to be gaining volume and no water mixed with your oil, it could be coolant mix mistake...G-12 can NEVER be mixed with other coolants, no matter what a label claims...a chemical reaction occurs, changing it's composition to sediment-forming and corrosive (to plastic/rubber fittings) brown substance.

If this is a case, the system needs a very thorough chemical flush.

Oil mixing with coolant, (which could happen due to improper seal(s) placement on oil cooler, cooler breached internally or improperly installed head gasket), should show up as beads or at least semi-separated blobs of oil in the coolant). Solid brown coolant, which should be pink only, with floating sediment would indicate wrong coolant mixed.

MikekiM@PureMS

Probably still have air in the lines.
Did they tell you if they vacuum filled the coolant?
Have them drain it, and fill it using a vacuum system. It eliminates air pockets, and prevents the problem you're having.

chicago maroon

When I got it back it had green coolant in there that the mechanic assured me was compatible with cars needing g-12. I made him empty it and replace it with the pink G-12 anyway. That is what has since turned brown, but it seems to have lost volume not gained it. It's possible that the loss of volume came with the attempts to bleed it. I don't believe it was vacuum filled.

tozoM8

He only drained the radiator not the block. you need to flush the whole thing out.

silverd2

Agreed...G-12 can NOT be mixed with even a small amount of other coolants...will turn to cloudy brown corrosive sludge. Chemical flush is what I would do...NO question...then refill with pink, red or purple G-12 (all compatible with each other).

Do NOT believe ANY label (or mechanic) that says you can mix anything with G-12, esp if it's not pink, red or purple.