Who has bled the cooling system on a B6 1.8T? I think it is different than the B5 (according to my searches). Any procedures appreciated. (diagnosticator1, you seem to know you're way around cooling issues, any hints?)

 

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thanks! :-)

 

Pretty good write up there.

I did mine a couple of months ago, and I tried to follow the Bentley and some other tips I found on other posts and for the B5 write ups. It's pretty easy, takes a couple of hours if you do like I did only because you have to wait for the car to cool down between flushes. Having some tunes or TV with a few beers help pass the time.

- Drain at bottom of radiator. No need to remove the bottom cover, but it doesn't hurt.

- Layout some cardboard under the engine, you will splash a little coolant, and you will miss your drain pan occasionally.

- Never found a bleed valve, guess I need to look again. Bentley did not refer to one of my MY '02.

- Drain when the vehicle is cold.

- Drain plug is actually the bottom coolant sensor held in by a plastic washer. Definitely buy a replacement washer in case you break the one coming off -- very cheap insurance. Also, buy a replacement O-ring that sits between the sensor and the radiator -- very cheap. Consider buying a replacement sensor -- if your sensor ever goes bad, which is known to happen, you'll need to drain/refill the system again due to losing coolant again. Make sure you get the right sensor, because the top and bottom sensors are different. Price is around $30-40 bucks from the dealer I think -- AoA recently raised the prices a bunch on these. Can also be found at a VW dealer, but make sure you get the right one.

- Pull off plastic clip holding the sensor in the radiator. Pull sensor by hand at a 90 degree to the radiator -- or straight out. Coolant will start to drain. Make sure you have the O-ring -- either still on the sensor, in your catch pan or still in the drain hole on the radiator. You need an O-ring when putting new sensor on, and you do not want to double-up the O-ring.

- Bentley says to take off the two coolant hoses that go to your oil cooler. This lets more coolant drain that is still stuck in block. The oil cooler is the metal piece that your oil filter screws into. I found that just taking off the lower hose will do the trick, as I had nothing come out of the upper hose. I figure 1-2 pints came out from this hose -- its some coolant but not a whole lot. These hoses have those pinch clamps on them, so they are a bitch to deal with. Also, I think I loosened/removed the coolant reservoir tank to help with access to these hoses -- accessed from the top side engine.

- Button everything back up.

- I then flushed my system with distilled water. Fill with the water as per the Audigeek write up, blasting your heater and getting the car temp up to operating temp. Let car cool, and drain. If your ****, drain the bottom hose from the oil cooler again. If your **** flush again. Never add cold water to a hot engine or you run the risk of cracking the block. Always let the engine cool down before adding any cold liquid into it.

- After flushing water, add the G12 coolant you bought at the dealer following whatever mixture you desire as per the label on the coolant. I do 50/50 mix. Use distilled water only. Remember, let the engine cool down before adding cold coolant and water into it. Coolant systems require much more maintenance than your Dad's old '70 Mustang or Camaro, and not all cars take the same coolant from the auto supply store. I only buy my coolants from the dealer -- its slightly more expensive, but spending an extra $10-15 bucks is worth the knowledge that your not putting the wrong stuff in your car.

- Other things to think on...

** Do not reuse your old coolant like your Dad did in his hotrods.

** AoA came out with a new coolant mix that is not compatible with the older coolant. You are not to mix these. I think my dealer mixed mine, because the color of the coolant I took out was brown -- brown was mentioned somewhere as an indicator of coolant being mixed. Flushing as mentioned will get rid of almost all old coolant.

** A plus to flushing is it remove any/most silica sedimentary that has built up on the system. This sediment may cause damage if left in the system. If you ever change a metal component/part of the cooling system (radiator, water pump, etc), I've read where it is strongly recommended to flush and fill with the system with new coolant -- never just drain enough to get the job done and top off with new coolant.

** Buy a few jugs of distilled water at the grocery store, its cheap. Never use tap water, it has minerals and additives that may not mix well with your new coolant.

** Buy yourself a plastic funnel at the hardware or auto supply store, its cheap. Use it to transfer the used coolant from your catch pan/bucket into the empty distilled water jugs. Label the jugs as "used coolant" and dispose of it properly. Remember, coolant is toxic-aly dangerous to animals and people if ingested. It's not going to hurt you if you get it on your hands. Most animals will drink it if left out because they like the smell. My four-year old would stick his hands in it then lick his fingers before I could stop him, so keep it away from any little kids.

** Buy yourself a metal drain pan at the auto parts store -- you'll use it for a lot of auto DIY stuff like changing oil, trans or diff fluid, cleaning brake parts, draining coolant. Just wipe out with paper towels after putting your waste into a proper receptacle. I'm still using the same one I bought 15 years ago. After years of use, it gains a nice garage-used patina to it that impresses all your non-mechanically inclined buddies when they come over for little things like burned out tail-lights.

 

but here it is circled in red....

<img src="http://i132.photobucket.com/albums/q33/x1rider/coolantbleeder.jpg">

 

Damn! ** Heads out to garage to bleed coolant system **

 

I changed my thermostat. Will it take awhile for the system to bleed air through the bleeder tube? I sat there for a long time with a lot of air and steam. The overflow tank went down slowly but I still couldn't get all of the air out (lost patience I guess). But I'm starting think it's my H20 pump that's causing the overheating since I'm not getting warm air inside the cabin. Also this seems to be consistent with it taking a while to bleed the system, the pump if not working isn't circulating the air trapped. What do you think?

 

I didn't have any problems when I changed my t-stat, the only thing is that it went above the middle mark (90) for a while and got back to normal. I added a bit of coolant to the expansion tank after the first ride and that was it. I'm not sure what to tell you.