Coolant flush

So my buddy liked my mkV TDI so much that he bought one.
He has had it about two months about 1000 miles, last night after his washer light went on, he filled the COOLANT overflow with RainX washer fluid.... then called me in a panic, LOL.

Since he is afraid to take the car to the dealership, he is coming over tonight, we are going to flush the coolant.
Anything we need to know before we start this? (aside from not letting him near the washer fluid)
Seems like 50-50% distilled water and G-12 is about the right mix.
Anyone flush the MkV system yet?
thx

It's going to be the purple coolant, G12+. dilution ratios are on the rear of the bottle.

Flush with distilled water and a BIT of coolant to keep the water pump lubed. Did he drive the car? If not suck out the coolant resevoir first. Remember the radiator drain is a twist and pull to open it. Put a piece of clear tubing 3/4" ID on the drain to direct the coolant to a catch basin. Otherwise it will run down the subframe and the front spoiler and end up everywhere.

If the car has not been run, siphon out the coolant bottle and refill.

If the car has been run, there's a drain cock at the lower left of the radiator. You can put a piece of tubing on the nipple on the underside of the drain cock. Then turn the handle on it 1/4 turn counterclockwise and pull out. It doesn't come completely out, just enough to allow the coolant to flow out.
Disconnect the hoses at the oil cooler.
This drains most of it, but there is still some left in the block. You'll have to remove the thermostat (follow lower hose to plastic adapter on the engine above the AC compressor) to get that out. It has an o-ring seal that should be replaced if you do this. Then flush as described in the alternative.

Alternative is to just flush it with distilled water by reconnecting hoses, close drain, fill with distilled, run a bit to circulate, redrain. Repeat as necessary until drained fluid is clear.

Then pour at least 3 liters, but no more than 4, of G12 into the system. Top up with distilled water.

He did drive it to work today, and will drive it to me tonight. He said it still looks like it is in the overflow- its an "orange/pink"- same as the RainX. Is the original stuff this color? I know the G-12 stuff is purple.

Thanks.

Original will appear pink. Yes, it has circulated through the engine now that it has been run.

Why the need to add coolant? Apparently it was low, but why???

He was trying to add washer fluid...

jasonTDI said:

He was trying to add washer fluid...

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D'OH!!! that was dumume.

Heck, I bet Einstein said stupid things liek that as well.

Well there is no draincock on the radiator of a mkV- dont know about the others though.

there is on the mk4's.... maybe the a5 fourum people would know? and maybe best he not add any fluids to his car

doc_m said:

there is on the mk4's.... maybe the a5 fourum people would know? and maybe best he not add any fluids to his car

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Don't pull that plug to drain the engine oil if he didn't remove any plastic.

Oops I missed that. There are quick coupling connectors to the radiator and you can remove the spring retainer and pull the lowest hose off the radiator. Or move the clamp and pull the hose off the coupler.