First - thanks to all who post questions and solutions to various odd little quirks we have to deal with being LR owners. I have a query regarding the cooling system as I simply cannot get the air out of the cooling system on my D2.
The problems:
1 - 'waterfall' sound in the dash - understood there is air in the cooling system - tried multiple times to purge the air following the exact RAVE steps as well as other procedures. I can feel the air pockets move in the heater core hoses while the engine is running.
2 - excessive pressure in the rad hoses - so much so that it had ruptured the expansion tank hose as well as one of the upper rad hoses.
3 - lower rad hose (before the Tstat) - cold
- the lower rad hose being cold leads me to believe the tstat is not opening at all - the TStat is new - not the softspring 180deg version though.
4 - aux fan turning on - assuming trying to cool the system.

all of this started after I had to tear the engine down to fix a massive coolant leak from the back of the valley gasket. while in there I did the HGs as well. I had no evidence prior to any cooling or HG problems only that the valley gasket sprung a leak.
This morning while trying to bleed the cooling system:
Engine cold
I lifted the new resevoir and removed the cap - removed the bleed screw - added water and watched as it simply exited through the bleed hole. - tightened the bleed hole and started the engine while the resevoir was still lifted and open. I ran the truck at 1500 RPM and carefully watched the tank - there are bubbles coming from the small throttle body return line into the tank. And as it warmed up it seamed to be less - this is the point where if I felt the heater lines I could feel the air pockets moving. I noticed while the tank was open i could also tell when the viscous fan would start to work as the truck heated up. I also noticed the lower rad hose warmed up - this led me to believe that while the system was not under pressure the TStat did actually open - allowing for the rad to do it's job, allow enough heat for the viscous fan to work and the aux fans did not turn on - I let the truck run like this for 1/2hr.
I have gone through many of the posts describing my exact issue but none actually post any solutions - they get 3 or 4 pages in and stop - that is less than helpfull.
Yes many new parts, rad, waterpump, hoses, resevoir tank, TStat etc...
and other than the cooling stuff going on it runs really well....
I've fixed many things on this truck but this one just stumps me. Thanks for everyone's input

 

Belt routed properly?

 

yes, belt is routed properly as are all the various coolant lines and hoses.- given that i had done a large amount of work I took pictures before for reference as well as had a friend stop in with his LR just to double check.
When all is working correctly you can hear when the viscous coupled fan engages and disengages. as with mine it does but only when the cap was off the tank while i was trying to get out the air.

 

Pressure in the hoses sufficient to rupture them doesn't sound good. Might want to test for combustion gases in the coolant. The reservoir cap should also release pressure before the hoses rupture so you might want to look into that as well.

As for the waterfall sound, that is from the heater core not being full. The top of the heater core is well above the outlet level so it will always trap air when you refill the cooling system no matter what you do. You need to run the truck on the highway for a while to get enough high velocity flow through the heater core to force out the air. On mine, it takes a few miles to get it out. Then it will move the the next highest spot which is the tee. Then you can purge it by lifting the reservoir and opening the screw.

When you did the cooling system work, did you backflush the heater core? Mine was pretty plugged up. I was shocked at how much it was choked off. I had almost no heat until I backflushed it. Now it cranks out the heat.

 

so have now just tested for combustion gases in the coolant - negative, so I am thinking that's a good sign. Maybe. Really am trying to get this air pocket out of the dash now - It just wont go away. I have another new TStat on the way as well as all new hoses. I will waste more of my time getting the air out after I put in all this new stuff.

 

try putting the truck on ramps, unscrew the bleeder screw refill with coolant until it comes out of the bleeder hole.

 

I picked up one of the cooling system pressure kits from HF and found several small pinhole leaks in various spots that were causing my gurgling water demon. Have you pressure tested your system?

 

no pressure test yet on the system. Once I have the new hoses and Stat in place I will do that. I will also need to somehow confirm the operation of the expansion tank cap - and not exactly sure how to do that. I can understand small pin holes letting air into the system once it has started cooling down and pressure starts to drop but my biggest issue is trying to get the air out from the very beginning.

 

The air in the heater core thing is something I have to deal with every time I do major work on the cooling system. People are always posting things like park on a hill, use ramps, etc. None of these things will work because of how the heater core is configured. The top of the heater core is much higher than the level of the outlet pipe so it is going to trap air. The only way to get the air out is to force enough coolant flow through the heater core to overwhelm the trapped air and move it into the rest of the system. I have had to do this three times. Once when I flushed out the dexcool and backflushed the partially clogged heater core, once after I changed the hoses, and then just recently after I did the head gaskets.

 

happen to know if there is a way to force the flow of coolant through the heater core with a hose to help the system purge the air? The major issue with mine is that as the pressure in the system increases it seams to be preventing the TStat from opening thus getting to an overheat issue which of course then prevents driving it to get out the air... a bit of a conundrum really.