Coolant: how low does the coolant need to be before a check engine light comes on?

[balabaika]

I recently purchased a 2011 C30-R. About a week later I happened to look under the hood, and I noticed the coolant level was about 4 inches below the minimum line on the expansion reservoir. At no point had there been a puddle, steam, or smoke. Moreover, the “check engine” light and never come on and the temperature gauge never wavered past 12:00 on the dash.

After initially noticing the low level, I dumped in almost a gallon of coolant, and over the course of about 15 minutes (car off) I watched the coolant level drop to roughly the same level as before — 4 inches below the minimum line on the expansion reservoir.

As I understand it, there is no “coolant level sensor” on this vehicle. That being said, it seems odd to me that the only mechanism for indicating this deficiency with an indicator light would be on the engine actively overheated.

Furthermore, in my research I came across a recall issued in the UK which describes my issue exactly:


ENGINE MAY OVERHEAT
Recall number
R/2010/144
Recall date
21-09-2010
Recall type
Safety recall

Reason for recall
It is possible that the hose connection between the coolant expansion tank and the bleed hose can work loose. If this should occur then coolant will leak and air will enter the system. Under these conditions the "low coolant level" warning light will not function. If the vehicle is driven in this condition it will cause engine damage and in the extreme possible failure.

My VIN falls within the range indicated in the recall...but is 2011, 2010.

I have two questions:

1) Is the vehicle performing correctly given its design, i.e. a check engine light/indicator light would only come on as the engine overheats?

2) Regarding the VIN year, any chance that there is some discrepancy (e.g., European manufacture dates vs US) that would allow a 2011 to somehow actually be a 2010?

3) If that is the case, why does the recall specify that the “low coolant warning” will not function?


Thanks