My Sienna appears to have lost something like half a quart of coolant, in the past 5000 plus miles (a period of about 6-7 months). I filled it up to just above the full mark earlier this year, and went out last week and had to fill it up some more. It was about halfway between the low and full marks. I just looked now, and a guesstimate would put about a full quart in between the low and full lines. The manual didn’t give any indication of how much that distance would be.
My question is—does coolant burn up at all? Or if the level drops, does it simply leech into the oil? I’m thinking about the effect of this coolant if in fact it did get into the oil. Its probably not providing good lubrication for my engine. After filling it to just over the full mark earlier this year, I noticed a blotch of pink goo on my driveway about where the engine is, so I know a small amount of it came out of the overflow tank, but that is the only time I’ve seen that, so this last half quart didn’t just bubble out.
Where does coolant go when the level drops?
- Thread starter paulri
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If it is leaking into the combustion chamber then it will "burn", at least the glycol portion. The water will vaporize and exit the exhaust system. If you think this might be happening then you usually can smell coolant in the exhaust. Don't breathe it too long of course but a quick sniff usually tells you if there is coolant present.
Coolant in the oil usually makes it look milky.
gathermewool
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1. Leak. Any white crustiness seen anywhere, such as the radiator seams? If an internal leak (e.g., head gasket) it may not be as evident.
2. Burping. When was the last time the coolant was changed? Has it burped between then and now before?
3. Evaporation. Seems like a lot for this to be the justification, but it happens over time, as a small amount evaporates due to leakage out of the overflow of water vapor from:
3.1. Heat cycles. Hot coolant expands into the overflow reservoir, and some vapor may escape.
3.2. High engine compartment temps. Hot coolant stays hot in a hot engine compartment, so even if hot coolant isn't expanding out of the radiator into the reservoir after the engine is fully warmed up, the hot engine compartment (e.g., stop-and-go-traffic in hot temps), may cause more evaporation, same as above.
I'll check the exhaust later today when we go out.
The last (and only) time it was changed was when my mechanic did the belts at around 120K. I know that's a bit too long, won't happen again...
This is Toyota Super Long Life coolant, so when it is flushed out, it can go 10 years. So I will just top off like I did last week, and let my mechanic flush & replace it every 100K with the belts.
Originally Posted By: gathermewool
1. Leak. Any white crustiness seen anywhere, such as the radiator seams? If an internal leak (e.g., head gasket) it may not be as evident.
2. Burping. When was the last time the coolant was changed? Has it burped between then and now before?
3. Evaporation. Seems like a lot for this to be the justification, but it happens over time, as a small amount evaporates due to leakage out of the overflow of water vapor from:
3.1. Heat cycles. Hot coolant expands into the overflow reservoir, and some vapor may escape.
3.2. High engine compartment temps. Hot coolant stays hot in a hot engine compartment, so even if hot coolant isn't expanding out of the radiator into the reservoir after the engine is fully warmed up, the hot engine compartment (e.g., stop-and-go-traffic in hot temps), may cause more evaporation, same as above.
I will do a sniff test later on today--but what type of smell am I smelling for now?
And there has never been anything milky at all--not around the oil fill cap or the baffle, nor when draining it. Its always been dark. So I guess that is a good sign.
Originally Posted By: kschachn
If it is leaking into the combustion chamber then it will "burn", at least the glycol portion. The water will vaporize and exit the exhaust system. If you think this might be happening then you usually can smell coolant in the exhaust. Don't breathe it too long of course but a quick sniff usually tells you if there is coolant present.
Coolant in the oil usually makes it look milky.
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I just went through this with my Jeep. I would lose about a pint a week. Couldn't find anything leaking. I was thinking the worst (head gasket) and then this morning I saw a little tine dribble on a cross member. I had to get under it with a flash light to find the radiator hose at the thermostat housing was loose and was only leaking under pressure.
The stain on your driveway is telling you of a leak. Most likely a hose or the water pump. A pressure test should quickly pinpoint the source.
Claud
I believe that was from the overflow tube coming out of the cap--it was just after I went over the full mark. Only saw it that one time, never again.
Originally Posted By: Claud
The stain on your driveway is telling you of a leak. Most likely a hose or the water pump. A pressure test should quickly pinpoint the source.
Claud
Originally Posted By: PimTac
I’m going to bet it’s your water pump. With your mileage on the Sienna it is likely. Just my bet.
Watch the water pump weep hole, Toyota SLLC can be hard on them. Amazingly I haven't lost one in the xB or the extended family's Matrixes (Matrices?) yet...
The coolant reservoir is open to the atmosphere and the H2O portion can evaporate over time.+1 on what bullwinkle stated above.
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