jav

This was the original post:

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Been looking around for instructions on how to "burp" my '02 allroad's cooling system. Coolant was low (my bad, wife's car and I don't play with it much) so we didn't have much heat over this past weekend with temps +/- single digits. Filled the coolant tonight and tried to find a bleed screw but no luck. Still not a lot of heat, but many bubbles coming into the expansion tank when I squeeze the hose that goes to the rad.

How do I bleed this thing properly??

Thanks.
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And here is the skinny on the list of symtoms. Facts are as follows:

- Car warms up normally and temp gauge comes up to within a whisper of the center line, used to come up to dead center
- Virtually no heat is put out by the blower
- setting the temp settings to full cold produces very cold air coming out of the vents, setting the temp to hot (ie. 80 degrees) results in warmer, but still cold air
- car has been burped numerous times in numerous ways
- there is some sort of coolant leak that doesn't make it to the ground, but can be smelled after the car has been driven for almost any period of time
- radiator hose (in front of the coolant tank) gets hot
- LOWER hose to the heater core through the firewall (next to battery) gets just as warm as the rad hose. UPPER hose remains cool or cold to the touch
- heater core has been flushed!!


I'm stuck. I cannot imagine what would cause the lower hose to heat up but no heat come out of the vents and the upper hose to remain cold. I ran the car for maybe 20 minutes - long enough for the fan to kick in - with the bleeder hole of the upper heater core hose exposed and nothing came out. No air, no coolant, nothing. Coolant is NOT being pushed through the heater core - I just cannot figure out why.

Anyone have any ideas?? Is it possible that that the water pump has failed and I'm just running off the electric water pump??


Thanks.

all(over)road

Try running the car parked with the coolant fill cap off and turn on the defroster and heater full blast. Let the engine come up to temp and when the thermostat opens, be there to fill up the coolant in the tank as it gets sucked in and the air escapes out. It might take 15-20 minutes to get all the air out. Be patient, it'll 'burp' a bunch of times.

Ken F

Running the front of the car up on some ramps will help also. This gets the overflow tank at the high-point of the cooling system.

Ken

swamper8

There is a bleed screw on this engine.

Of the three triangular plastic shields on the engine, remove the front one. look down between your drivers side diverter valve and throttle body. Down about 6" or so there's a allen head plug. Maybe 6-8MM. This is the bleed screw. Supposedly, with the engine off, you're supposed to be able to loosen that, fill the system from the resevoir tank and all the air will be pushed out this plug. Once you start seeing anti-freeze coming out of the plug you should be good-to-go. I've only read this, have not tried it. Some additional "traditional" burping may be necessary.

all(over)road

On my car at least...the over-flow tank IS the high-point of the cooling system. 8-)

jav

Found the bleed screw - thank you very much. I'd had that cover off before looking for a bleed screw of some sort, but without your directions, I would not have found it.

Started the car up and cracked that bleeder open just a tiny bit not knowing what to expect. It hissed for nearly 2 minutes and then dribbled a very small amount of coolant out. I closed it back up and let car warm up. I cracked it a few more times while the car warmed up and after I took it for a test drive but didn't get any more air out.

So the good news is that the bleeding instructions were spot on. The bad news is that I still don't have a car that heats like it used to.

This all started with a little low coolant. My bad - the wife's daily driver and I don't get under the hood much. I'm a little curious as to where the coolant went, but it was low when I checked it after a recent road trip in VERY cold temps. The car never got very warm, and the air from the defroster and heater was lukewarm at best. I originally thought thermostat, but the car seems to come up to temp and run fine....unless of course the "temp guage" isn't really a guage, but rather a fancy idiot light.

What's next? Will a VAG tell me what's up?

swamper8

I would say you still may have one of the following:

1.) maybe a large air pocket in the heater core loop

2.) maybe a partically clogged heater core.

2.) maybe a blend door in your HVAC system that is not open/closing properly (mixing cold air in with the hot air)

I believe the temp gauge is accurate. Does it climb to exactly vertical? (Straight up and down) If you accelerate quickly or go on the highway does the needle drop a little? If it does your thermostat may be stuck OPEN.

jav

So, not exactly vertical, but very close. Doesn't seem to move with rapid acceleration or on the highway, but it's not something I have specifically looked for.

I tried to find the coolant hoses that route to the heater core to see if one side was hot and the other cold, but I'm not sure where they are....not like there's a lot of room to poke around in there. And when the wife got home earlier, I smelled coolant.
YIKES!

I'll be out there looking again tonight.

5v/cyl

This might explain how the coolant got low in the first place. Could be as simple as a leaking line. Problem is finding it.

951 driver

If you opened the bleed valve in the valley up front that may be the source of the coolant odor.

For heat you may need to bleed the heater core. The top heater hose next to the battery has a circle marked on it: that shows the location of a hole in the hose. Remove the clamp (push it toward the firewall) and pull the hose back until you can feel/see that the vent hole isn't on the pipe, then run the engine until there's coolant coming out. Turn the engine off, replace the hose and clamp and you should have heat.