coolant flushing, can i do it like this?

[coupegt]

my coolant looks like it could need a total flush and renewing. (just bought the car, S2 3B)

Normally i would remove the top and bottom coolant hose to the main rad and the termostat, so i could flush both the engine and the rad this way.

But looking on the engine (and after reading some post on this site) the thermostat seems to be tugged away below the power steering pump and alot of other goodies i really dont want to be messing with right now.

So i was looking at the back of the cyl. head and found the hoses for the cabin heater core (two hoses going trough the bulkhead, one of them coming from the cyl. head.

So now im thinking that i could just pull these two hoses and flush the heater/engine this way, and then pull the top and bottom hose on the main rad, and flush the rad this way.

Would i get a complete drain this way?

How do i get the heater core open when the car has a/c?

Then planning to top up with the g12+ audi coolant and distilled water, and be happy about it for a couple of years

[Pete_RS2]

That's how I flushed mine. I just removed one of those bulkhead heater hoses and the rad bottom hose. It seemed to drain most of it out.

Turning the heater to max will open the heater core will it not ?

[coupegt]

ok then, problem is that my car is with electronic a/c.

Well, it's nice enough to have in the car , but i dont have a heater knob i can turn to max, just two small bottons with "warmer" and "cooler" and they dont do much without ignition swithced to "on", but maybe that is the solution.

ignition to on, and then max on the climate control panel, and then do the flushing.

[NoNonsense]

ok then, problem is that my car is with electronic a/c.

Well, it's nice enough to have in the car , but i dont have a heater knob i can turn to max, just two small bottons with "warmer" and "cooler" and they dont do much without ignition swithced to "on", but maybe that is the solution.

ignition to on, and then max on the climate control panel, and then do the flushing.

to do a proper flush, you need to empty all the coolant out, then refill with distilled water (and a flushing aid if desired...prestone makes a good one), turn the car on and have your heat set to HI...then run the car until it gets to operating temperature...that's the only way you'll truly get the gunk out of the heater core. then let it cool, then drain it and either flush again or refill with coolant.
When I bought my car, the coolant must have been 9 years old, it was brown!! It took me about 5 consecutive flushes to get the water clear....

[coupegt]

ok thx, sounds reasnoble and i will try it, but could you not just flush with tab water, if you finally refill with G12 and distilled water. It hardly could make deposits if just in the engine a few minuts to make it warm???

Im also a little afraid that my coolant is the original, as it seem very dark in colour, and the car only has 96000 km on it when i bought it. That's why i want it changed quickly

[NoNonsense]

ok thx, sounds reasnoble and i will try it, but could you not just flush with tab water, if you finally refill with G12 and distilled water. It hardly could make deposits if just in the engine a few minuts to make it warm???

Im also a little afraid that my coolant is the original, as it seem very dark in colour, and the car only has 96000 km on it when i bought it. That's why i want it changed quickly

you can use tap water to flush, but I'd recommend one quick fill and flush (you don't even need to bring it to temperature, just run it and bring the revs up to 2.5K for ~30 seconds) of distilled water before filling with coolant and distilled water.

Remember, never add cold water to a warm engine, it may warp the head...you must let it cool completely!

[A1QSHIP]

ok then, problem is that my car is with electronic a/c.

ok then, problem is that my car is with electronic a/c.

Well, it's nice enough to have in the car , but i dont have a heater knob i can turn to max, just two small bottons with "warmer" and "cooler" and they dont do much without ignition swithced to "on", but maybe that is the solution.

ignition to on, and then max on the climate control panel, and then do the flushing.

If your car has electronic a/c then the water valve is closed by applying vacuume. This is also the "fail safe" feature that will cause the interior vents to move to the defrost postistion when auto a/c system fails or looses engine vacuume. Long story short, when the ignition is off the water valve is open and will allow coolant,water,flush to flow.
Chris

[porkkis]

Time for one strange detail here.

RHD cars have a heater valve. LHD cars do not have a valve. That's right.. in LHD cars the heater matrix is hot all the time engine is hot and temperature level is adjusted by restricting air going through the matrix and pass the matrix.

For the original question.. I would loosen the PAS pump etc to get to the thermostat. I flushed mine several times by removing the thermostat for draining on every cycle.

2nd best option is to loosen the hose behind the block that goes to the matrix. Downside is that the coolant will be in your clutch.

When refilling, rev the engine a bit, say 3krpm. This makes the coolant flow. Letting it just idle don't bring out the air and you have a possible over heat situation...