nyrobbie77

ok.. so looking at the parts diagram, the heater hose i've been calling the upper, the one to the left if standing at the front and looking at the firewall, runs down and t's into the hose coming from the reservoir. the parts diagram lists it as the return hose, which makes sense that i haven't had any pressure in it.

i haven't tried disconnecting the right/lower hose to see if i have flow. i have noticed its difficult to spray water thru the right/lower outlet thru the after run pump towards the heater core. perhaps the valve in the pump for the inlet is closed off after all. am going to try to disconnect/remove the after run pump tomorrow.

will update with what i find.

silverd2

Sorry...I realized I got those 2 lines reversed...have never had a problem, myself, with the coolant circuit there before.

Haven't checked the temps on them while running, but after car is off for a while, I found my return hose (left/top) hot and the lower right supply hose cool...that's why I assumed the reverse, because mine is and always has worked well (normal).

Now I'll have to check the temps while running warmed up and heat on...curious now.

nyrobbie77

water pump is pumping! i disconnected the other hose, the right/lower hose, had flow at idle and increased with revs, so water pump is definately pumping. i had been ignoring the right/lower hose as we all thought it was return, but is actually the inlet. makes sense that it was the hose always getting warm and the other one cold.

its difficult to spray water towards the heater core from that hose, so best guess now is that the valve is stuck in the after run pump. am going to have to pull the pump and see what i find.

it'll have to wait for a week or so, am going on vacation on friday for a week. walt disney world here i come!

does anyone have any tips on getting that lil monster out? i'm a little confused by the picture of the unit back on page 1 of this thread. shows 4 metal pipes, but the two that are closest together in the pic seems to be on the opposite side of the pump assembly on my car. or are there actually 6 hoses?

thanks again all.

silverd2

Yep, 6 hoses...the main engine-side heater hose connections are out view in that photo. The other 4 connections are supply and return hoses for each of the 2 heater cores.

Brake booster has to come out, plus the top of the HVAC intake (flap panel) and a plenum reinforcement piece.

If you decide to remove it, I can get you more specific details (Bentley manual).

nyrobbie77

that'd be great. will be tackling it next weekend when we get back from our trip.

thanks again!

chicago maroon

I don't have a fix for you.

During work to fix oil leak at the front of the engine, I had the oil cooler replaced, water pump, a head gasket, cams, etc. When this "Former dealership mechanic" gve me the car bac, it had no heat and was actually blowing AC when it should be heat. After some time running the car I noticed green coolant. I was told, this is newer stuff that is fine for your car. I made them swap it for G-12, but still no heat. Weeks later, I noticed my "coolant" in now that brown sludge others have talked about. Another local show wants to replace the control valve in the post above and see it that fixes it. The Audi dealership here in Charlottesville, VA wants $4,972 to replace that and the two heater cores. With 146,00 on the car, it's not worth that especially since I've been driving it for 60,000 miles with the transmission hunting issue this car is infamous for. My plan is to drive another car until spring and never fix the heat unless it's something easy and relatively cheap. My stereo is worth more than the car. See the link. I will continue to read this thread in hopes you find a fix eventually.

http://www.crutchfield.com/S-M2jlHGX...satellite.html

nyrobbie77

IT'S OUT! thanks for the tips on pulling the brake booster and the upper shrowd on the fresh air intake silverd2.

verified that i can't blow thru the inlet portion of the pump, and i can blow through both heater cores just fine. i decided to try to pull the pump apart (can't make it any worse right?). found all kinds of tan/brown sludge inside it (pictured below). looks like someone may have put the wrong coolant in which then froze up the pump. haven't pulled it all the way apart yet, need to get some pipe cleaners to clean out the passages.

its a neat little thing. looks likes it uses electro magnets to open/close the valves and another to act as the pump.

i'll add a boo-audi on their choice for their little screws that they put all over the fresh air intake box and aux coolant pump. if they stayed dry, they look and work fine. if they were anywhere that got wet, the heads are all rusted and very difficult to undo, some even snapped off.

will update again when i put the pump back together. hopefully i can fix it and make it work again or if i have to buy another one (ouch).

nyrobbie77

sludgy goo

silverd2

Very cool...have never seen one disassembled before. A past mix of G-12 with the wrong coolant would be my guess too. What a great example to show others.

I've seen this sludge in a coolant reservoir, before a full chemical flush (absolutely necessary after a mistake like that)...the car (VW) later developed leaks at plastic heater hose fittings, anyway. That sludge is not only clogging, but corrosive to some plastics...didn't seem to effect rubber hoses and seals, though.

I wanna hear if you get it working. I would think that cleaned up and sealed properly, you have a good chance.

Thanks for the photos and progress report.

nyrobbie77

and I said - let their be heat! getting 151 degrees F out of the vents. should keep us warm

i ended up finding a used replacement valve at a great price, so ended up putting that one in instead of cleaning up my old one. school has started again and i have a baby due any day now, so didn't have a lot of time to mess around.

the replacement really isn't that bad. can easily be done in a day. i still have to bleed the brakes, and have a couple electrical things i need to figure out (am making a new post). thanks again to all, and special kudos to silverd2 as he nailed it on the first post.

looks like the whole trouble was from someone putting the wrong coolant in and clogged up the valve. thankfully the heater cores were clear as a bell.

again, thanks all for the help!