Coolant Disappearing

[Turkish]

So I am finally below the low line on the overflow tank, so while my car is back at the dealer for the rough idle CEL/SL issue (for the third time), they're going to top off the coolant.

[FR-S Matt]

Originally Posted by Turkish

So I am finally below the low line on the overflow tank, so while my car is back at the dealer for the rough idle CEL/SL issue (for the third time), they're going to top off the coolant.

Hopefully they don't take it to the full mark while it cools down.

[Turkish]

Originally Posted by FR-S Matt

Hopefully they don't take it to the full mark while it cools down.

If they do and shit blows up, that only helps my case. I hate having to think that way.

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[JDKane527]

I have the Robispec radiator/oil cooler combo and noticed last night that my coolant after driving had been low when hot, just at the minimum mark. The coolant temps were normal, but the radiator fans were running at full, which made me think something was abnormal. I added some distilled water and we'll see how it goes.

Today was able to lift the car and noticed some coolant at the plastic access door on the passenger side underneath the car, so I'm hoping it's not a major leak. The drain plug has some residue so I'm going to try and remove the front bumper sometime this weekend or next to check out what could be the culprit. I have 19k miles, 5k miles since the radiator was installed.

Update:
Determined that the drain plug was the source of the leak. I was able to tighten it about 1 full turn. While the drain plug was loose, my coolant temps read over obd2 were 205-215F. After tightening the drain plug, temps were back at 190F, which was normal. Coolant wasn't exceeding the 1.3bar radiator cap since it was escaping out the drain.

[m.wood0213]

Noticed mine after nearly 1 year, when cold I couldn't see any fluid. Put about 1/10 of a gallon to fill it to the halfway mark between low and full. When hot the line is just over full and now when cold it's just above low. I haven't noticed any white smoke coming out the back yet or anything indicating a BHG. Coming from Toyota 7M engines I know a bit about BHG lol.

[leon78]

Just picked up a gallon of toyta blue b/c mine is now below the MIN line. 9400mi

[stugray]

Originally Posted by Suberman

High compression engines run slightly cooler. That's where the extra power comes from, more thermally efficient.

Sorry Suberman, but I am going to have to call BS again.
Raising static compression ratios DEFINITELY increases engine head temperatures. I race air cooled boxer engines (Type-IV) and the number 1 reason to be careful in increasing CR above 10:1 is increased chance of engine failure due to increased head temperatures. That is why I need to run Cylinder head & Exhaust temperature sensors on the racecar.
Increased head temps results in knock which is obviously one of the most critical concerns on this engine.

Now with the VVT system on this car, the dynamic CR can vary based on tune, so it is not apples to apples, but last time I checked PV-nRT still applies (higher pressure equals higher temperature)

[autobrz]

Originally Posted by Turkish

If they do and shit blows up, that only helps my case. I hate having to think that way.

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shit... i checked my coolant level today and it is completely empty in the overflow tank... do i just get the dealer to top it off?

[Turkish]

Originally Posted by autobrz

shit... i checked my coolant level today and it is completely empty in the overflow tank... do i just get the dealer to top it off?

That or just buy some from the dealer and do it yourself, mine is in the shop anyway though so I might as well have them top it off while they're under the hood anyway. Either way, yes you should fill it up!

[FR-S Matt]

Originally Posted by autobrz

shit... i checked my coolant level today and it is completely empty in the overflow tank... do i just get the dealer to top it off?

If you get the coolant yourself, I advise filling it only to the halfway mark while cold. I filled mine to that point and when it warms, it goes to full. I haven't checked it in a few weeks now to see if its dropped but I will. I was under the low mark when I filled it up.

[notout86]

To eliminate doubts about incomplete air bleeding at the factory.

After say 3000Km, I would say that you should ensure your overflow tank level is somewhat above LOW when cold. If not, add Coolant or distilled water =< the FULL mark. Pencil-mark the level.

Drive car to normal temp and allow to cool e.g. overnight.

Check overflow again is near the previous. If the ambient temp is higher than the previous time when you checked the previous time you may even notice the level is higher , and vice versa.

Check actual radiator is full to the top. If not, fill with distilled water or coolant. This should eliminate doubts about incomplete bleeding at the factory or accumulation of dissolved air driven out of coolant.

From then on, the overflow level should stay pretty much fixed, except for the inevitable slight evaporation via the overflow. That would be the water component as glycol scarcely evorates? A bit of reflective foil heat shielding to the engine side will help.

If the level continues to fall, go back to the dealer and report your efforts.

If any of this is wrong, don't hold back the corrections.

[ZionsWrath]

Car has 22,000 miles. Just did an oil change and notice overflow tank empty.

Bought a gallon of coolant. Opened radiator and poured 1 ounce or less and it was full.

Opened overflow tank, and it filled VERY FAST (just a couple ounces)

Initially I was concerned but seeing how it ended up being only about a couple ounces of coolant I feel it is not that big a deal.

Time will tell.

[mabviper]

I just want to add my experience with this. I did my oil change a few weeks back at 9500km and I noticed that my coolant levels were kinda low, about 20% level from low to full.

I went to the dealership and told them about the issue and they gave the car back to me with a report saying they refilled 300mL of coolant. It was just above the full mark when the engine is hot. Fast forward to today, less than 1000km more, the coolant level is now under the full mark when the engine is hot.

[FR-S Matt]

Ever since I filled mine up last month, I'm still at the full mark at warm, halfway mark at cold. No changes.