Losing Coolant

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SF0059

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Aug 6, 2012
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Lynchburg, VA, USA
In my Audi in the signature. I'm losing about half a liter of coolant every 2-3 weeks. This has only started since it started getting cold outside. I've looked at all the radiator hoses and there are no leaks. The radiator is pristine. The coolant looks spotless in the overflow tank.

There has been no change in the oil level and it does not look milky at all. I'm going to pull a sample for UOA this weekend, but it does not appear to be making its was into the engine.

This leaves me with the heater core. The heat is working fine and I don't notice any coolant or "sweet" smells. Occasionally on start up the heat will cause condensation on the windshield, but this is neither frequent or excessive.

What do you guys think? I'm at a loss and I'm getting tired of pouring G12 in there... stuff is too expensive. Any help would be appreciate. Thanks!
 
you're either leaking it or burning it. any white smoke/steam from the exhaust?

If the heater matrix was leaking you'd have wet carpets and sweet smells..

I'd be tempted to pressurise the system and go through the whole thing with a fine tooth comb until I found it - shouldn't take more than an hour or so
 
Have you checked around the water pump pulley, sometimes it can leak out the weep hole after you drive the car and stop when it gets up to temperature. This is a hard leak to find unless you start the car and turn it off in 2-3 min and let it sit for an hour.
 
My Fiat is loosing coolent at a slow rate. I brought it in yesterday for a service and had them do a pressure test, and they couldn't find it.

That seems like a decent DIY kit, I'd try it out
 
Wonder if a seam on the rad is leaking at a certain point of the expansion/ contraction phase when warming up or cooling down.

Same with hose clamps.
 
Sane here on the FIT, which is relatively new. I chalked it up to an air pocket that got purged due to heater use in the cold weather and more vigorous expansion and contraction and thus flow into and out of the overflow bottle. But my windows are fogging aggressively and I cant find that issue yet - no wet carpets or spare well.
frown.gif
??!
 
To hear near-new cars (FIAT/FIT) having issues like that already,makes one wonder,how are those cars going to make it to 10 years old...15...20??
 
I had my coolant flushed and filled last year, since than the level dropped from almost full in the overflow to just above the low mark. Topped it up to the full mark but am guessing between low and full is about 1 quart. I am guessing you must have a leak or something somewhere to use that much every 2-3 weeks.
 
I am planning on doing the timing belt myself in the Spring which requires the removal of the radiator. If it can hang in there that long I will replace all the hoses while I'm in there. It is still troubling that it is seemingly disappearing.

There is no white smoke from the exhaust. I vaguely remember last year the passenger side floorboard carpet was wet, but there was no corresponding coolant loss and it never reoccurred so I chalked it up to a small obstruction in the sunroof drain rails that washed away.

In doing some research on the Audi forums I have found the same issue described for the 2.7T engines that is blamed on a bad auxiliary water pump, but it appears the 2.8 does not have this part.

I guess I will go ahead and buy the dye kit this weekend. I'm planning on changing the spark plugs and wires this weekend, so I will take a closer look while I am in there.

Truly baffling.
 
If it began when the weather got cold, that suggests you've been using the heater more and the leak is at the heater core or hoses leading/to it.

Otherwise the other places to look are radiator cap & water pump
 
One possible scenario is that you may have an o-ring somewhere that only leaks when it's cold. This could be losing a dribble that dries up without ever reaching the ground leaving nothing behind but a crusty stalactite in a spot that you aren't going to look. If that's what you have you can get a tester to pump air into the cooling system to pressurize it early in the morning while it's still stone cold. Let it sit pressurized and cold for a half hour or so and you may see drips show up.
 
I ventured under the Audi today... evidence of coolant everywhere. The belly pan was catching it so that is why I didn't see a leak. I tried to track down where it was coming from. There is some dripping down the oil filter, but the oil cooler does not appear to be leaking. The water pump is on that side, so I'm starting to think a seal failed. On the other side of the engine the radiator hose is leaking where it enters the block. At least I know it is coming from outside the engine.

On top of that, the valve covers appear to be weeping some oil, the PCV system needs replaced and I saw today that the spark plug wires have some dry rot.

Some major surgery needs done. Now I need to figure out whether I want to tackle all of it myself or just take it to a German Auto guy. I hate paying people to do stuff I can do, but I'm not sure I have that kind of time and I don't have a garage.
 
I believe the water pump is a bit of a job on that vehicle, but you can find timing belt/water pump kits and plenty of how-to guides out there. Check out what's really involved before you make the decision.

That's what finally killed the Audi for me. It wasn't costing a lot of money in repairs, and even the complex ones weren't always that daunting. I just didn't have the time any longer. I wish I did; I miss the car.
 
Typically such Audi models recommend removing the radiator to reach the t-belt and water pump, and others recommend removing the front bumper, AC condenser, and radiator to make room.

I don't believe this is something you would want to do in a parking space.
 
I took it to a mechanic a buddy of mine with a TDI Jetta recommended. It is indeed the water pump. I had some other things that I wanted done. Here is the breakdown:

New water pump
Timing belt, tensioner pulley and hydraulic tensioner
Thermostat
Serpentine belt and tensioner pulley
Radiator flush and new G12
Transmission filter, fluid and Lubegard platinum
Valve cover seals
PCV tubes and valve
Spark plugs and wires

I already had some of the parts, but even so the repair is going to cost $1385 out the door, which I thought was incredibly reasonable. Pretty happy not to have to do it in my driveway, too!
 
Originally Posted By: SF0059
........
New water pump
Timing belt, tensioner pulley and hydraulic tensioner
Thermostat
Serpentine belt and tensioner pulley
Radiator flush and new G12
Transmission filter, fluid and Lubegard platinum
Valve cover seals
PCV tubes and valve
Spark plugs and wires .........



Good maintenance list to get done at the same time!!
She should purr real nice now !!!!!
 
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