HOW DO I FLUSH & REPLACE COOLANT

[jonnyedinburgh 0]

Just replaced aux water pump, now want to completely drain cooling system and refill. I;'ve also got some holts stuff to remove deposits in the system. I've read various bits on this site advising how to changes coolant. Is anyone able to confirm the following?

- i want to drain the system using th bottom rad hose, is this the thin one to the bottom left of the rad when stood facing the engine?

- will draining this way completley drain the system? what position should the heater be set to to ensure no water is left in the matrix?

- when refilling the system i've read that it shouldn't be done via the expansion tank, to use the rad top hose instead... it looks like my rad top hose is too horizontal to be used to top up (as well as being vary narrow and awkward to try and pour 10 lites of fluid into), what is your advice on refilling the cooling system, any tips to ensure air doesn't get trapped on system too?

- once filled what should be done next (for example should i run the engine then top up)?

ALL ADVICE, IDEALLY A FULL GUIDE WITH EXPLANATION OF LOCATION OF ITEMS ON THIS MATTER IS MOST WELCOME AS I NEED TO REPLACE COOLANT ASAP AS I DON'T HAVE A CLUE WHAT CONCENTRATION OR HOW OLD CURRENT COOLANT IS! many thanks

[shail 0]

You can use the bottom rad hose to empty the system, but from experience it doesnt remove all the coolant. There is a drain plug on the VR6, its located on a plastic pipe which runs horizontaly on the front of the engine. You can get at the drain plug from below the car using a long screw driver. The plug will need replacing - couple of quid from VW.

Heater controls should be on HOT when draining.

I refill via the expansion tank. Just refill using a funnel, and very slowly to lower the amount of trapped air - you'll always get some, so you need to run the engine until the rad fans come on, thenremove air by opening the expansion tank (be carefull as it'll be well hot!) You can also remove air by running the engine with the cap off.

Once filled, keep an eye on it, it'll need topping up for sure.

As for concentration, it'll tell you on the bottle. Remember to use VW G12 PLUS coolant available from GSF or from your VW dealer. Using other coolant can cause problems as it may react with whatever you had in previously, the G12 PLUS can be mixed unlike other coolants.

To flush it properly you need to get hose pipe, remove the bottom rad hose and run water through it for ages. I'd advise to fill the system up with just water, run it until the rad fans come on, then flush it all, and then re-fill using the coolant. You'll never get all the gunk out by the way.

How much was the aux water pump by the way? Mines making a right racket.

[28v6r 0]

£86 notes!! From Stealers...:-(

[fabio_vr6 0]

do the aux pumps always make a loud noise before going?

[fritzenberg 3]

somebody do a full guide whith pics PLEASE!

[jonnyedinburgh 0]

thanks for the advice. my aux pump didn't make any noise before it started leaking, i'm just pleased i found out it was leaking before it busted big time and dumped coolant everywhere! i bought my aux pump (bosch genuine part) from eurocarparts... £69.95 + VAT (free delivery). New pump has 4 screws to hold it together better (old one wasn't screwed and pulled apart easily)

I've bought mobil 1 advanced coolant, same spec as VW G12+ and recommended by VW (doesn't require distilled water, tap water is fine) £15.00 for 5 litres from Halfrauds. Aux pump was a c*nt to fit due to the fiddlyness of attaching hoses, also newer design of pump meant it was tricky getting it to fit into the bottom rubber ring mount (had to remove mount and fit pump first before reattaching mount and pumpo to metal frame).

Leak appears to have been fixed, i topped up coolant with water and cheapo halfrauds coolant so i can drive to work all week and test cooling system for leaks, if all is well i'll drain all coolant and replace with mobil 1.

then it's MOT time....... %-6