Need help bleeding coolant. Wits end!

[ethelene]

I just did the BSM delete and a new torque converter. My local guru who is more of a ALH guy did the delete, water pump, and timing belt. I got it back and it ended up needing a temp sensor and thermostat. I replaced both and bled the system as prescribed by pulling the heater core hose and lifting reservoir tank. It does not build pressure and starts to overheat as soon as the thermostat opens. I have bled it, or at least thought I was probably 10 times now and have had no luck resolving this. Today I put my vac on the bleeder hole thinking it may help. I'm super frustrated and to give my daughter my Golf R as she heated up on her way out of town. Any help/tricks would much appreciated. I called Oilhammer's shop while on the side of the road but just missed him.

 

[Uberhare]

Possible the waterpump is not turning on the inside?

 

[ethelene]

I'm wondering that also. Coolant hose is totally soft when the engine is running.

 

[zzdiesel]

A rag or some such got left in the system, maybe.

 

[oilhammer]

Is the coolant flowing? You should see it coming through the little vent hose into the bottle.

Why did it need a temp sensor and thermostat after the timing belt? What was the basis for that?

The BHW won't make enough heat at idle to boil over... it barely makes enough heat at idle to cause the thermostat to open (and that takes a LONG time).

Is there warm air being drawn through the radiator by the crankshaft driven fan?

 

[ethelene]

My GURU told me today that it is not a pressurized system so soft hoses are out.

 

[ethelene]

OK I posted that before I refreshed. I'll check the warm air tomorrow. The T stat was not opening after delete and there was a code showing that also. Justin (local guru) told me to change it and the sensor at the same time. That was why we changed those. The "STOP DRIVING NOW" alarm came after I pulled a big hill getting a Christmas tree the day I swapped them. That was my first indication of overheating. I borrowed tools from the tree farm (I'm in Oregon) and bled it there again. It continued to send the gauge to the red which caused me to pull over immediately and let it cool down. It did get hot but I was careful to not let it get to the top of the gauge besides the one time getting a tree. I thought I had it bled and fine because I drove it for a week and it never got hot. Granted my commute is only a few miles so maybe it wasn't enough to warm it up. Yesterday my daughter made it 10 miles down I-5 when she pulled over and called me panicked because it was starting to rise above normal. I swapped her out and limped it to my shop and bled with my vac pump over the heater hole. That is where it sits now. It runs perfect BTEW and is only 125k mile car. The BSM delete was the second time because the initial unchaining at 65k was so shoddy the oil pickup bolts were loose along with a bunch of other missing bolts etc. That was why the delete now.

 

[oilhammer]

They most certainly do have a pressurized cooling system. It is just that the diesels take longer to heat up, thus longer to build any pressure. And they cool DOWN at idle, so there may be a drop in pressure after idle for a few minutes, especially if it is cool out.

I've refilled more BHWs' cooling systems than I can remember, as well as countless AWMs and ATQs.... I have never had any issues with filling them. But on the diesels, you do need to drive them quite a bit to make sure they are full. A full heat cycle may take 20+ miles of driving in cooler weather, but usually not that long. They heat up much quicker under load. Again, idle does very little. They are just too efficient.

And once again, I ask: is the engine driven fan pulling warm air across the radiator? Is there good coolant flow through the vent tube at the top of the bottle?

 

[thundershorts]

Its really easy to remove tstat and check wp impeller at same time for spinning on shaft. If you still have old tstat you could gut it and try running it to rule out bad tstat.

 

[Mozambiquer]

Did you follow the procedure for bleeding the cooling system? You have to pull the cowl cover and take the one heater hose mostly loose (it has a hole near the end) move it where that hole is past the end of the pipe it connects to, then fill the coolant, otherwise you'll have an air bubble there, and the coolant won't flow. I like to pull the coolant reservoir and lift it up a bit to make it go faster, since that makes the reservoir higher than the vent hole, and liquid goes to the lowest place. There's a whole procedure for it in the B5 faq

 

[oilhammer]

You do not even need to do that. It'll push the air through the core. And these cars (the BHWs in particular) often have the gurgle through the core when cold anyway. Mine did it since it was new. My AWM doesn't. The EGR cooler's situation in the heater core circuit is the reason.

 

[compu_85]

My father's AWM had a gurgle through the heater core from the day he picked it up in 04. I never tried bleeding it.

At a Ho5G get together, I helped someone with a BHW who was complaining about bad heat output purge the air from the heater circuit. An amazing amount of air came out of the little vent passage, and he'd driven some distance to Peter & Julie's!

-J

 

[Mozambiquer]

You do not even need to do that. It'll push the air through the core. And these cars (the BHWs in particular) often have the gurgle through the core when cold anyway. Mine did it since it was new. My AWM doesn't. The EGR cooler's situation in the heater core circuit is the reason.

Mine didn't have any heat, but the heater core was completely empty because it had a failed egr cooler that pushed the coolant out. After removing that and bypassing it, there was no heat. I did some checking and found that procedure for bleeding the cooling system. After that, I had heat again!

 

[ethelene]

I'll report back today once I get to work and can drive it to warm it up. It gurgles when when you start it. The warm air test results will be forthcoming. Thanks everyone for the time and attention.

 

[ethelene]

There is no coolant flowing through the vent tube. I did not run it long enough to check for warm air across the radiator. The water pump is new so maybe radiator is plugged?

 

[oilhammer]

Assuming the new water pump is OK (but as noted, this is easy to check by peaking in where the thermostat lives), you could also have a clog in the vent tube. Mixing coolants other than G12 can clog those little passages up.

There are two vent hoses on the BHW: one from the back end of the head (near the passenger side of the tandem pump), and the one to the bottle. Both attach to the big chunky crossover pipe that the upper radiator hose goes to. It is unlikely the big tube is plugged, but either of the smaller ones could be. Remove them both from the pipe (right up top near the glow plugs) and see if you can push air through them.

 

[thundershorts]

As mentioned earlier in the thread, are you sure the viscous rad fan is functioning properly. They do go bad. Another diagnostic tool is to hook up a pressure gauge on the expansion tank then drive car and see what happens with cooling system pressure.

 

[ethelene]

This gives me a good list to go after. For now I have an allroad for my daughter to use in the mean time. I know the top tube is clear because I can squeeze the big radiator hose and it pushes coolant into the tank. If I pull the tstat do I just hand spin the water pump or start it and see it spin?

 

[Mozambiquer]

The water pump is driven by the timing belt, so you'll have to start it. The timing belt was just replaced, correct? Was the water pump replaced at the same time? They're supposed to be replaced together.

This gives me a good list to go after. For now I have an allroad for my daughter to use in the mean time. I know the top tube is clear because I can squeeze the big radiator hose and it pushes coolant into the tank. If I pull the tstat do I just hand spin the water pump or start it and see it spin?

 

[ethelene]

Yep. Both replaced during the BSM delete.

 

[thundershorts]

Don't start, reach in with your finger and try to spin the impeller. You should not be able to move the impeller. With a mirror you should be able to tell if its metal or plastic.