Renewing coolant.....Bleeding

I am just about to replace the coolant in the Alp and have come across an interesting point ( well I think it is interesting ) having flushed out the system by removing the rad and the two engine drain plugs, I then went looking for the bleed point on the Thermostat housing, Having found it, I realised it would not bleed the block like I thought it should, it is above the thermostat, so I removed the housing to see if there was a jiggle valve in the stat...there isn`t so trying to bleed the block through this point wont happen because with the stat closed the air cannot be displaced as the coolant tries to rises in the block. So what I am going to do is remove the plug on the side of the housing below the stat until the coolant reaches that point then at least the coolant will have reached the stat and filled the block.
I really cannot see why they have put the bleeding point where it is as the air can just be vented back along the large hose and up into the reservoir......... unless someone knows better
Pic below shows the plug half undone below the stat, bottom left, and the bleed point on the upper stat housing top right.




I would welcome your comments.

John

I always bleed it from the top nipple and it seems to work OK .I doubt you could even get an air lock in the block .It'll bleed out through the rear outlets and to the matrix ?
The plug is where the ECU sender lives on the Turbo .

Not sure if this helps... but back in my Pontiac Fiero days (very similar car in design and layout). There was a "Burp" procedure for bleeding air out of the system.

You basically jacked the front of the car up as high as you could, and then with the engine running, keeping an eye on the temp. Bleed the air out of the Rad. Since it would be the highest point.

I doubt you could even get an air lock in the block .It'll bleed out through the rear outlets and to the matrix ?

Which rear outlets and which matrix are you talking about? In my view it can only bleed via the top nipple if the stat has a jiggle valve, then the air can escape. My stat is the original with no valve

The replacement thermostats I have used have the "jiggle valve". Just drill a 3mm hole in the plate of the thermostat. Bleeding the air out will be easy. Yes it might take another 30 seconds to have the engine reach full temp after doing this, but not a big problem.

Make sure your bleed from the rubber hose at the radiator is clear, as they seem to collect "mud".

Just drill a 3mm hole in the plate of the thermostat. Bleeding the air out will be easy.

Yes Alan, I thought of that but decided against that, as I can remove the plug, and the block will fill quicker....but a very good point to make

I've had some fun with this in the past and have used both Paul's Pontiac technique (having found the same approach described for a Fiat X-19) and the technique in the workshop manual.

I was used to bleeding the coolant on my old Fuego by hooking the expansion tank as high as possible (easy as it had a long tube to the top of the radiator), opening the bleed screws until the coolant comes out, closing them, running the engine until the thermostat opens and then do the bleed screws again. So, I was looking to the same thing on the GTA but initially couldn't find the thermostat housing bleed screw.

So, I went for the get the front of the car as high as possible, run the engine and bleed from the radiator. Of course, I discovered that I needed to clear out that bleed hose. I think this did a good job of bleeding the coolant but the it was very hot and the location of these compared to my old Fuego made this difficult and despite being a bit ready for it I scalded my hand getting the bleed screw back into the radiator despite wearing Marigolds with surgical gloves underneath. That coolant was f***ing hot by this stage! All related to clearing the sludge in the bleed hose. Never had this kind of 'fun' on the Fuego.

As a consequence of all that and after reading the workshop manual on this site, I took particular note of the comments that say that you should NOT open the bleed screws with the engine running.

It's interesting that the manual says to get the expansion tank as high as possible (anyone found a way of doing this in the GTA?) implying doing the same easy thing as on my Fuego and R5 where it was held in with a large rubber band on a long hose.

Anyway, next time I managed to find the thermostat bleed screw and used this and the radiator bleed screw with the engine cold and off and all seemed well. I suspect that there's an element of auto-bleeding into the expansion tank from the top hose that goes on when you run it. Hence the comments in the manual about checking the level in the expansion tank after running the engine until the thermostat opens / the radiator fans come on.

I agree that it seems weird to bleed it cold with the thermostat shut but it seems to work and compared to the older Renault engines, it certainly doesn't appear to be designed to be bled hot with the thermostat open.

It's interesting that the manual says to get the expansion tank as high as possible (anyone found a way of doing this in the GTA?)

I am going to jack the back of the car up so that it will fill from the rad back to the engine, mainly to slope the long under car metal pipes up at the back so, in theory all the air will be removed from them.....well thats what I hope

Decided to have the rad pressure tested and it was found to be fine ,......jacked the back of the Alp up and refilled with Renault type D coolant, went out for a long run and only had to put in a further half litre to top up, and no air in the rad.
What did surprise me was the total lack of crud in the system when I emptied it, not even in the rad, and there was only very slight discolouration in the old coolant, which was replaced about 12 years ago, again I used the Type D coolant. Comments from others seem to suggest the Rad and bleed tube gets crudded up