Coolant Replacement.

Hello,

I am wanting to replace the coolant.

I have found very useful threads on how to do it etc which i am fine with. One question i have however is i have read quite a few times that the Heater controls need to be set to MAX whilst doing so. I have no idea how you do this so if someone could show/tell me and explain why it needs to be done that would be great.

Thanks!!!! 

Just move the temperature all the way to HOT, (bottom slider all the way to the right), this then opens up the valve in the engine bay so the coolant in the heater matrix will flow out when flushing the system or when refilling it will replace the coolant in the heater matrix (it's like a little radiator inside the car)  

Worth removing and replacing the thermostat when changing the coolant system as thermostats don't last forever.

mark1gls said

Just move the temperature all the way to HOT, (bottom slider all the way to the right), this then opens up the valve in the engine bay so the coolant in the heater matrix will flow out when flushing the system or when refilling it will replace the coolant in the heater matrix (it's like a little radiator inside the car)

Worth removing and replacing the thermostat when changing the coolant system as thermostats don't last forever.

Be sure that your new t-stat matches the one removed Temp wise as the t-stat, and the Radiator Fan Switch should be a matched set and both tested prior to installation using a Thermometer and Boiling water.

If you drill a 1/8 to 1/16" hole in the lip of the new t-stat you won't have any "air bubble from hades issues"  just be sure that you fill the block, then fill the radiator.  Do both sides equally which usually will eliminate the Air-bubble.





Shown installed in the proper orientation, and be sure that you use a new t-stat o-ring.

mark1gls said

Just move the temperature all the way to HOT, (bottom slider all the way to the right), this then opens up the valve in the engine bay so the coolant in the heater matrix will flow out when flushing the system or when refilling it will replace the coolant in the heater matrix (it's like a little radiator inside the car)  

Worth removing and replacing the thermostat when changing the coolant system as thermostats don't last forever.

Sorry i may be being really stupid here!
I still am unsure of what you mean by moving the slider?. How do you do that?.

Apologise.

The control knob inside the cabin, just below your radio, you use it the adjust the temperature inside the car (move that one all the way to the red dot) there is also the sliders for adjusting the air to the windscreen and one to direct it to your feet, next to it is the control knob for the speed of the blowers, setting 1,2 and 3…

The panel looks like this.

https://www.ebay.co.uk/itm/VW-GOLF-JETTA-CADDY-MK1-CABRIO-HEATER-CONTROL-PANEL-FASCIA-TRIM-321919383B/152760009304?hash=item239134c258:g:Q~kAAOSw43hZ8eZ9

Chadwick235 said

mark1gls said

Just move the temperature all the way to HOT, (bottom slider all the way to the right), this then opens up the valve in the engine bay so the coolant in the heater matrix will flow out when flushing the system or when refilling it will replace the coolant in the heater matrix (it's like a little radiator inside the car)  

Worth removing and replacing the thermostat when changing the coolant system as thermostats don't last forever.

Sorry i may be being really stupid here!
I still am unsure of what you mean by moving the slider?. How do you do that?.

Apologise.

no worries, it is moving the Temperature arm (slider) from the all blue area to the all red area on the control panel.  

If your engines heater valve isn't fully seated against the stop you still need it in the red area.

non/ac control panel.


a/c control panel


Heater valve explanation of positioning. (courtesy of www.cabby-info.com) Thanks Kammy.

mark1gls said

The control knob inside the cabin, just below your radio, you use it the adjust the temperature inside the car (move that one all the way to the red dot) there is also the sliders for adjusting the air to the windscreen and one to direct it to your feet, next to it is the control knob for the speed of the blowers, setting 1,2 and 3…

The panel looks like this.

https://www.ebay.co.uk/itm/VW-GOLF-JETTA-CADDY-MK1-CABRIO-HEATER-CONTROL-PANEL-FASCIA-TRIM-321919383B/152760009304?hash=item239134c258:g:Q~kAAOSw43hZ8eZ9

Oh wow well isnt that embarrasing!!!

Apologise for my stupidity not sure how I didn't understand that haha!

Briano1234 said

Chadwick235 said

mark1gls said

Just move the temperature all the way to HOT, (bottom slider all the way to the right), this then opens up the valve in the engine bay so the coolant in the heater matrix will flow out when flushing the system or when refilling it will replace the coolant in the heater matrix (it's like a little radiator inside the car)  

Worth removing and replacing the thermostat when changing the coolant system as thermostats don't last forever.

Sorry i may be being really stupid here!
I still am unsure of what you mean by moving the slider?. How do you do that?.

Apologise.

no worries, it is moving the Temperature arm (slider) from the all blue area to the all red area on the control panel.  

If your engines heater valve isn't fully seated against the stop you still need it in the red area.

non/ac control panel.


a/c control panel


Heater valve explanation of positioning. (courtesy of www.cabby-info.com) Thanks Kammy.

Thanks for the explanation! I have no idea how I didn't get what you guys were saying, my bad!!

Cheers again!

No worries, pictures are always the best way to explaine things but most of mine are on photobucket which does not work now.  

mark1gls said

No worries, pictures are always the best way to explaine things but most of mine are on photobucket which does not work now.  

That is because they upped the price of the "Free" membership.  Open an account with IMGUR. You should be able to download your pictures  from photobucket to your personal computer of choice.  Then you have to open the IMGUR and upload them to there.

IMGUR is free at the moment, but that is probably apt to change.  

mark1gls said

No worries, pictures are always the best way to explaine things but most of mine are on photobucket which does not work now.  

Very true.

Whilst im here, can i ask, how do i know which Thermostat i need to buy to replace my current one?. i have seen that there are variations in the ones you can buy due to the temperature range?.

Thanks!!

some recommend lower temp stat, so that rad fan kicks in earlier,  but if happy how was work prior to coolant change remove the old one and you will see the temp range of one fitted.

The type I've got in both my cars.. 87 degrees C opening..

https://www.eurocarparts.com/ecp/c/Volkswagen_Golf+Cabriolet_1.8_1989/p/car-parts/cooling/car-cooling-parts-and-car-heating/car-thermostat/?209440040&1&c01e4844afd3a7f2e3f03130e2053c29a40e4e54&000325