Coolant removal/Thermostat Housing Replacement.

[CraigW]

As thread title suggests I have my thermostat housing to replace as some point, Im hoping this weekend.

1st question, What is the best way to drain all the coolant out??

I read the 'suggestion' in the haynes manual but it isnt that easy to follow.

2nd question, Any suggestions for getting the old housing off without sheering bolts or anything?

Cheers.

 

[Reuvers]

to drain fluid simply follow the lowest collant pipe from radiator. I usually take it off the watrpump (bucket underneath) but remember to open the coolant cap as well. Then I usually stick a garden hose in the coolant reservoir to wash out all the gunk.
Bolts should give way, but if not WD40 is your best friend

 

[Undert4ker]

Also worth backwards flushing the radiator with a hose while everything's off, run the hose into the bottom until clean water comes out of the top.

Can't remember if the Book of Lies mentions these but there's an awkward bolt in the middle of the housing, in between all the pipes which isn't obvious, and a plastic circlip on the long plastic pipe running along the back of the engine which holds in to the housing. Apart from that it should all go well, have fun

 

[Reuvers]

are you changing the waterpump side of it too though?

 

[CraigW]

Im not planning on changing the water pump at this time. Do you think it would be a good idea to?

 

[Reuvers]

well I don't really see why you're changing the thermostat housing then? Or do you simply mean the thermostat??
Because if you're changing the housing you might as well change the pump which its connected to.
Bolts are indeed prone to snap which connect the pump to the house, so be very careful when undoing them. I advise you to soak them in WD40 before you start putting force on them.

 

[CraigW]

well I don't really see why you're changing the thermostat housing then? Or do you simply mean the thermostat??
Because if you're changing the housing you might as well change the pump which its connected to.
Bolts are indeed prone to snap which connect the pump to the house, so be very careful when undoing them. I advise you to soak them in WD40 before you start putting force on them.

I had the expansion tank go a few months back and was causing the coolant to leak when at full working pressure. And the extra heat has made the plastic move every so slightly so that it isnt sealing correctly with the end of the pipe that the thermostat pin is in, hence it is leaking from there.

 

[CraigW]

Right Im after abit of help and advice. As above I fitted the thermostat housing with a new thermostat,coolant sensor and a new batch of coolant.

Started my car yesterday morning and let it run for a bit to clear frost, started my journey and the temperature gauge sat at half way for the 20ish miles. Stopped the car at my destination and left it for 10-15 minutes, came out and drove it and once again the gauge went up to halfway and stayed there. Went to another few places and the same happened again. I then started on my way back and the temperature gauge started of halfway but then dropped all the way to the white. Stopped the car just before I headed home and before I set off I left the gauge to go up to halfway and started my journey and once again it dropped all the way down to the white.

All the coolant is flowing through the pipes and radiator and returning to the coolant tank.

Any suggestions?

Cheers as its really doing my head in.

 

[M1KEH]

Sounds like your new thermostat could be stuck open.

 

[CraigW]

Anyone else have any other suggestions what it could be??

Im really puzzled by it, if im honest.