I just ran into an issue where my coolant levels went low and the reservoir froze. I added more coolant to my 75:25 ratio for winter but it was really cold one night. The car ran fine but I was doing some testing with my car and had the throttle at about 2500rpm when I noticed at my tailpipe that there was a bit of smoke. It wasn't thick but it smelled like water and a little coolant. The smoke went out about 3 feet before dissipating.

Is that just the normal vapor in the exhaust or the beginning of the engine eating coolant? Its about 35 degrees out. I know cars generally have a bit of vapor in the winter but its the smell after having some of the coolant freeze that worried me.

 

Did it go away the more you drove. And was it a 1 time thing or does it constantly do it now and what generation car you have ? (Year/model/motor/mileage) it helps us easier define a possible issue .

 

97 Accord Ex with 204k. Which is part of the reason I'm double checking this. This just seemed a bit more than typical and the smell worried me. Its not what we think of when a car has a blown head gasket but it was consistent, white, smoke with the smell of "burning water". I suppose I should drive it more or do a compression test.

It was kinda like this only shooting out cuz the car was at 2500rpm. At idle theres no smoke which is why it caught my attention (higher rpm and more strain on the engine causes coolant to leak in)
From my experience it's hard to tell whether or not its coolant or the usual water vapor.

 

If you smelled coolant it is most likely from the outside of the engine. I would pressure test the cooling system.

 

I suppose I will have to. Coolant burning could be from the outside. Hope its nothing. Too cold for engine work >.>

 

Reservoir froze when it went low; kinda hhmmm. 75% what, 25% what?
I used to do 55% antifreeze, 45% distilled water all year, mixed myself.
Now I just buy the prediluted 50:50 stuff.







FWIW, that's no different than my car.

 

I did 25% coolant, 75% water and water wetter. Made a difference in my engine temps which was nice. Not that my car was overheating but the radiator is old so it allowed for more cooling through the radiator. Come winter I added about 15-20% more coolant after draining that much of the 25:75. I calculated that it shouldve been good down to -5. It was an 8˚ morning. Maybe the reservoir wasn't the same ratio though. But that morning I had to fill up the radiator with almost half a gallon. The idle went crazy and the heat wasn't working when I warmed up the car. Turned out that was the problem but I'm not sure how that happened. No leaks.

 

Sure sounds like coolant is making its way into the combustion chamber: an internal coolant leak.

 

I should specify that the idle sounded like a vacuum leak with the engine revving and then the injectors cutting out. But that could be a bubble going through the FIT valve while the ECT sensor reads a 180˚ coolant temp. I turned off my car and then waited a while and then check for a leak. Nothing. The car behaved fine until I tried the heat. The car isn't behaving horribly, nor is the exhaust smoke excessive. I can't see it in the rear view mirror when driving. A significant loss in coolant would be seen by a big cloud of white smoke right?

So compression test or coolant system test?

 

Either test could be useful. And you could check spark plug coloring when you do the compression check. A plug that looks like it's been steam cleaned and/or has a green tinge indicates coolant in the combustion chamber. A leakdown test would tell for sure. Unless it's going through a lot of coolant, it shouldn't hurt anything to continue driving & adding coolant until the weather warms up.