The coolant level in the sonic was low by just over 1 L when I added more water there were some bubbles..I drove it around the block then while it was parked it still gave some bubbles, I noticed the water level bouncing. Should this be happening? why is the water bouncing?

This morning I had to add another Liter of water after it sat overnight. The engine started up fine and I didn't see any unusual white smoke from exhaust or any water on the ground.

I added another 1/2 L then drove for about 45 minutes in town and almost no change in coolant level. I wonder if I lost coolant because the cap to reservoir was loose.
If water did evaporate then only water and not coolant would have evaporated so adding water would be OK and no "coolant" would need to be added? Does that sound right? Also, would there be any significant damage to engine if 3.5L coolant was in the system rather than 6L (of which about 0.5L is for the reservoir).

Sounds like it was really low. When you filled it and bubbles came out, this was probably air working its way out of the system.

The big question here is: Where is the coolant going?

My suggestion: Since it appears to otherwise run properly, keep refilling the coolant until it stops going down. If you've driven it, let'* say, 100km and you're still having to top it off over and over, it might be time to look for a more serious issue.

I drove 80km yesterday with no change in coolant level. I can keep driving and monitor coolant. My concern is coolant concentration is diluted and diluted coolant boild more easily. Is this going to boil and increase pressure and cause problems in the system? It is currently summer so I am not worried about freezing right now.

You should always fill with a 50/50 mix.

Too much concentrated coolant in the mix can cause poor heat transfer. Too little will increase the chance of boiling.

Always use distilled water when mixing with coolant.

I have already put in tap water. Is this a big deal requiring a flush?

I have added concentrated Dexcool to bring mix closer to the 50/50. Did this by siphoning out about 0.7L multiple times from reservoir and adding concentrated dexcool. Will have concentration checked with densitometer.

I have heard that dexcool tends to cause problems like gasket leaks..Is this old news and recent formulas better? I am asking this as I have dexcool but am wondering if I should switch to universal coolant if dexcool has problems.

I am expecting to keep the car 3-5 yrs.

Not the end of the world. Kind of depends on how much you added versus the overall capacity.

C=Capacity
D=DexCool concentrate
L=Coolant Loss
T=Tap water
W=whatever is in there
X=variable
Y=variable

(C-L)+X(T)+Y(-0.7L(W)+0.7L(D))=Current level and ratio

Solve for X and Y

It'* better now, and the parts in the engine are better for it.

Figure out where the coolant is going before planning for longevity.

From pages 10-15 through 10-20 and 11-12 of your owner'* manual:



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