Your point is debatable. You sir, may have just opened a can of worms.

According to the manual I am correct. It specifically states mixing coolants reduces the life.

Factory fill is good for 11 years or 132k Miles. Mixing your coolant reduces the life to I think 30K miles or 50k Miles, but I know it's reduced significantly.

I have had to top up my coolant level twice in 3 seasons. There doesn't appear to be any leaks and this seems to be par for the course with this car.

Agreed that one should use Toyota or Subaru super coolant vs. mixing or adding distilled water to maintain the extreme longevity of the product. One jug should last several years.

In general people really ought to consult the owner's manual when they observe a potential issue with their vehicle.

I DID consult the owner's manual. Nothing says "hey, you might lose a gallon of coolant in less than 2 months of regular use. Keep a gallon on hand to regularly top it off."

Interesting thread. There are only two possibilities in a closed system, a leak or coolant escaping through the combustion chamber. Judging by what the experienced engine builders are saying about the FA I don't think its the latter. By leak I don't necessarily mean a drip that can be seen. With older coolants there was typically some white chalky residue visible around the leak. With modern coolants it's harder to detect. I'd start with the cap and move on to the hoses if it continues. Its not normal no matter what anyone's says. In the old days the system would sometimes vent, often overboard. But these are modern closed systems, closed being the key word.

I couldn't find the part in the owner's manual that says mixing coolants reduces life, but I do believe you that mixing certain coolants will decrease coolant performance/life, and can even solidify and clog up the system when mixing the wrong chemicals. However, the coolant I mixed with the factory coolant is ethylene-glycol based and silicon free, so hopefully nothing catastrophic will happen.

I'll flush the coolant earlier than normal to be on the safe side. Next time I'll wait until I can get my hands on the OEM coolant before adding any.

I noticed the same on my FR-S, although it is just above the low line. Purchased at the end of May 2014, and have 6k on it. Had and oil change check up in December.

There is a pretty long thread on this already. Multiple people have it with no real known cause. Looking for any hint of leaks (ie residue) has not found anything yet along with compression test, leakdown test, etc. Just keep an eye on it and top it off when needed.

http://www.ft86club.com/forums/showt...hlight=coolant

Another thing you guys can look for is, "WHEN" did you check your coolant level?
Was your car warmed up enough? Or did you just check the reservoir all of a sudden after the car has been sitting still for a while?

You will be able to see the coolant level rising after a car is warmed up a bit... surprise! lol (would like to put meme here but I won't...)

With that being said, I did however put a little more coolant (subaru blue) that I got from a Subaru dealership. No problems since then.

Thanks!
 

I just wanted to thank the OP for posting this.

I read it then decided to go home and check my reservoir tank.... it was bone dry as well. I waited till the engine cooled and checked the radiator which thankfully had coolant it. Not sure why the overspill tank would boil off like that I've never had a car that did that before but I know now to check that often as well....

Car only had about 6k on it at the time. Thanks again! :cheers:

Here's an interesting write up.

http://www.audizine.com/forum/showth...nt-amp-Testing

That's a great experiment you found. Apparently Supertech coolant is manufactured by Peak. Now I want to go flush my coolant right away! Should I have the dealer flush my system, or should I try DIY following Grimmspeed's guide?

Also, I found a thread here about someone who also mixed their coolant with peak 50/50 (like I did :bonk:). The answers there varied from "flush the coolant system" to "don't worry too much about it".

There are other threads on this. Ranging from bad hoses, hole in the overflow tank, etc.

Mine also had the same issue during the first few oil changes the coolant level always dropping. No smoke, no overheat, no spill on the floor, the hoses are clean. Checked the oil cap and no sign of mixing with oil.

I just topped it with distilled water. Now no more, mind you I live in desert climate so if it hasn't dropped in 4 months then I guess it should be ok. Probably they didn't bleed the radiator properly in the factory.

If that's really true.... I gotta flush my coolant.. lmao