DINA

<ul><li><a href="http://www.pentosin.com/eng/products/antifreeze/antifreeze.html">Pentosin Antifreeze</a></li></ul>

cuatrokoop

Coolant temp sensors, there are several. However, I think only the MFTS feeds the gauge. The MFTS is the large 4 wire (new ones are only 3 wire) mounted at/near the thermostat housing. The coolant level sensor is a float integrated into the expansion tank, non-removeable, connector is just a two(?) wire deal just pull/wiggle straight down. Does the gauge work properly? May want to see if there is more information on 20v.org WRT temp sensors. There may be a 2nd sensor that can trigger a warning, but I don't think there is?

Also, just run antifreeze/coolant that is phosphate and silicate free. Most are nowadays. I can't remember which coolant the 5cyl's came with from the factory. I thought the difference between Red and Blue was that one was "long-life".

YucatanAudi

Green is definitely not correct for any I5cyl.

I don't know enough about the "orange" to say if it is OK or not. It is a new formulation by other mfgs and not specifically recommended by Audi. When researching this question for a friend who recently bought a VW Jetta (and couldn't believe he had to go to the dealership for special coolant), we found sites saying that the mix of Green with Blue or Red could cause the coolant to actually 'gell' in the engine.

So, make sure all the green is completely flushed and there's nothing but clear water draining from all parts of the car before you use Blue or Red.

You can't go wrong by using the Blue or Red versions directly from Audi or VW -- as long as you flush all the old stuff COMPLETELY from your car - block, heater core, radiator, aux radiator, everything! I got the Red Coolant from the local dealership and it wasn't horribly expensive.

Distilled water is definitely the best to use, since it will not contain minerals that could build up.

As far as long-life, I believe Audi found the Blue wasn't remaining sufficiently protective for long enough, so they created the Red version. I can't find where I saw that right now tho....

DINA

Red = silicate-free, like Dexcool (orange) - so Dexcool is 'OK' to use on your 20v (i5), but not grn

YucatanAudi

Is that true for Orange?

Pentosin is the maker of the Red &amp; Blue sold at VW and Audi and other suppliers....

cuatrokoop

nitrate and amine free.

But yes, the orange Dexcool is fine. Green, you just need to check. Many new American cars use aluminum heads and even blocks, so they require the same type of coolant that our cars have for decades.