I've been having an issue in my 2003 4.6 D2.
Bought it as a non runner last winter, did heads, gaskest, cam etc to it and have driven ~6000km since.
I have the inline thermostat kit with port up and a temp sensor.
Coolant temps are fine.

All the time it has had the famous waterfall sounds in the cabin, coming from the heater matrix.
Mostly heard when accelerating when the waterpump spins more. I put in a new waterpump when I did the engine.
Did not pay much attention to the sound during the summer, as the temps were good and no heat needed inside.

Now that I have been driving it in the winter (up to ~-25 celcius) I really could use proper heat in the cabin.
It will blow warm, but not even close hot as my TD5 does.
Winters can be over -35 celcius here at worst.

All the hoses will get warm and feel soft, so no hard nor cold hoses.

So there really should have been enough heat cycles to get all the air out according what I have read.

I tried bleeding with the front ~foot higher than the rear.
Lifted the expansion tank up as high as I could get it, cap off. Let it sit for the night.
The next day let it idle up to temp, give it some revs over 2000rpm for about a minute.
And turned it off.
Coolant had spewed out the expansion, glad I had the cap on loosely, just a bit on the threads so it stayed on.
Let it cool down, expansion back to normal etc.
No help.

Well, was doing something on my TD5 and did the exhaust leak test to my V8 at same time.
Had the tester on the expansion.
Up to temp ~75 celcius or something above it when I went to turn it off.
I noticed that the coolant was just rising to the tester and was above the cold max line on the tank.
Oh, an no exhaust in the cooling system.

Turned it off and removed some coolant from the expansion tank.
Havent driven it properly after that, just moving it around and the waterfall stil is there.

Have searched around plenty and have not found any definitive resolution to this issue or they have not helped yet.
I wouldn't like to revert to the original thermostat setup that the locals around here are suggesting.

Anyone have anything else for me to try out?

 

Park it on a steep hill, or jack up the front and try bleeding again.

 

I recently revised the bleeding instructions, have a look in the support section of inlinethermostats.com. The main change is you want to rev the engine before the thermostat opens, about 130-140. With the thermostat closed revving the engine will force all the coolant through the heater matrix, cap barely one lets the air escape. Give it a try and report back.

 

Thanks.
I'll test that as soon as the weather warms up a bit.
It's -25c until weekend now..

 

I had the waterfall as an early indicator when my old engine blew up. I hope it's not the case with yours. After installing a new engine and an inline thermostat I noticed the waterfall, but it went away on its own just by driving. That your coolant rises so high is a bit suspicious to me (I am driving around town with a lose expansion tank cap in order to get the air out after I did work on the coolant system). Did you try a pressure test of the cooling system? Also a vacuum bleeder helps to get air out, especially after a refill from dry.

 

Yeah, I'm a bit worried about the level rising too, but then I realised that there is air in the system, and air expands when heated, right?
But if it expands it should make way for itself out of the matrix...

Have just tried the normal bleeding procedures and haven't got a pressure test done.
For a diy pressure test, is it enough if I fab myself a cap with a schrader valve or something to be able to pressurize the system? I do have an extra cap or two..

Also haven't noticed coolant loss and the coolant is clean.

 

Well, started heating the sauna and water and thought I'd fiddle with Betty in the meantime.

Lifted the expansion tank, loosened the cap so it's just barely on the thread.
Let it idle for a while and then started giving it some ~2500rpm for some random seconds intermittenly.

LOT of waterfalling can be heard.

Momentarily there was coolant overflow from the small overflow pipe when I had the cap just barely on.
I took it off completely and continued. Did not notice anymore overflowing.
Removed just a little bit of he coolant from the tank at some point just to make sure no overflow.

Noticed that the small hose that comes from the top corner of the radiator started spewing coolant into the tank at some random times, and as thats next
to the overflow pipe, I suppose that was what came out of it when I had the cap on loosely.

I had it idling for some more time and had it blowing max hot air to the windscreen and it actually started melting the ice on it and side windows.
The heated screen is a no go, as there is only 3 or 4 wires that work in the whole screen.
And it's ~-20C (-4F) now.

Now the waterfall sounds have gotten a lot smaller, but I will see again tomorrow when the engine and coolant are cold again.

 

For pressure test I use a rubber plug, a Schrader valve and a reservoir cap. Drilled a hole into the rubber plug to fit the valve stem. Drilled another hole into the reservoir cap to have access to the valve. I screw on the cap to secure the plug with the valve stem. Never go over 1.4 bar, use a hand pump with a gauge. Let it sit for several hours, there should be pressure left although the pressure might decrease a tiny bit.

 

Brilliant. Thanks Discorama.

 

I fill mine buy removing one of the heater hoses were it comes out of the bulkhead an fill the engine via the heater