VZ Alloytec 3.6L Water Pump/Cooling System Flush

[pau13z]

Hi all, I know this has been covered a bit before but I have a couple of questions that I think are valid...

I've seen the workshop manual on how to change the water pump, but there are 2 things that I need to know.

1 - When changing the water pump do you need to first drain the cooling system? I assumed you did but people have posted instructions about doing it without draining/bleeding it first.

2 - It's recommended that the cooling system in the Alloytec use the red 50/50 long life coolant. Mine has green coolant in it, which makes me think whoever worked on it last was a gumby. So What I need to know is.. how do I do a full flush?? Now I've seen in posts people have put up the workshop manual pages on how to do this... Basically you need to connect the heater hose outlets together, disconnect the bottom radiator hose and blast water through it until it comes out clear. The real problem though, is that one of the instructions is to remove the thermostat from the thermostat housing to fully accomplish this, and from what I've seen on here nobody has mentioned actually doing that. Now being located at the back of the engine it's obviously not easy to do. Has anyone actually done this? It makes sense, but is it also necessary? I've heard that it's bad to have the 2 types of coolant together in your system so I want to make sure it's completely flushed out...

Cheers guys.

 

[pau13z]

Anyone????

 

[RiCeY]

1. You dont have to but if you dont, coolant will piss out when you undo the pump.

2. No need to remove the thermostat too much work.

 

[pau13z]

Just an FYI for anyone who has to do this in the future. There are 3 ways to completely flush the coolant from the engine:

1 - Remove the thermostat from the thermostat housing, reinstall the thermostat housing and flush water through the cooling system. When it runs clear you're set.
2 - Remove the knock sensors. These are located under/behind the extractors, so you'll need to remove them first. Not an easy job but easier than the thermostat housing. Flush water through until it spills out of the knock sensor holes. When it runs clear you're set.
3 - The longest and most frustrating, however the easiest, and the one I went for. Drain the radiator using the tap and by removing the lower radiator hose at the engine. Fill with water and run until the thermostat opens, mixing the fluid. Let the engine cool (this can take 2-4 hours easily) and repeat this process 2-4 times. At this point you should have most of the original coolant out of the system and you can fill it with the correct stuff. Considering there will still be around 5L in the engine you can simply fill the radiator with the concentrate rather than mixing 50/50 and when the thermostat next opens it will mix the coolant for you.

 

[RiCeY]

The knock sensors simply bolt to the block, they dont enter any coolant galleries.

 

[pau13z]

That's how the Haynes manual says to do it... Just going off that.