So the other day I was greeted by the flashing red Engine Coolant warning sign just after starting the ignition on my 2003 A4 1.8t. This was the first time I started the car after having returned fromthe dealership's repair shopjust a few hours before. (two ignition coils, AGAIN.)

When I called the repair guy at the dealership about it, he told me I needed to just add water to the coolant tank if the level were low. If this didn'tturn off the warning light, then I'd have to take my car back to them so they could fix the sensor.

Thinking this sounded reasonable, I checked the coolant level and found it was indeed too low.

However, just before filling the tank back up w/water, I recalled something about needing to maintain the right proportion of water and a coolant additive in order for the system to function correctly.

Here's where I need your guidance:

Should I go ahead and just add plain water to the coolant tank, as the repair guy said? Or is it best toadd a mixture of water andcoolant additive?

I can't help but think that if there's too much water vs.coolant additive, the coolant would freeze and wreak havoc on the engine. Especially in the brutal Chicago winter temps.

Thoughts?

 

Depending on how much you need to add you'll probably be safe to just add distilled water. It is always safer to add a mixture of both coolant and distilled water though. The ratio of water to coolant is usually 50:50 and as the ratio becomes more biased towards water (meaning more water than coolant) the tempature to what you will be protected will rise, but not drastically. You can pick up a gauge at any autoparts store that can measure your coolant to be sure you are staying at a safe mix.

Add straight coolant if it really worries you. Just be sure of why it's low, sounds like you've got a leak.

 

Use G-12 antifreeze only. Mix 50/50 with
distilled water.

 

Thanks. Based on these suggestions I'm going to get G-12 antifreeze and add it to the coolant tank along with distilled water (50/50).

 

Update: I bought G12 antifreeze from an Audi dealership in Chicago for $22.00. Added this to the coolant tank w/distilled water (about a 50/50 mix). This seemed to turn off the warning indicator when I started the car again. Thanks for your suggestions!

 

is the coolant red?? it should be because it should be long life G12

 

Sorry for the delay in responding - yes, it was red.

 

Excellent, but now you have to determine where the coolant is going. Keep and eye on it and see if the level is going down.

 

Absolutely great point. Will check often.